Michelin Airless(michelin.com)
michelin.com
Michelin Airless
https://www.michelin.com/en/innovation/vision-concept/airless/
315 comments
Complete layman here, every 6 months or so for the past decade I see an article claiming someone got air-less tires working. What are the chances this would be it ?
Air-less tires have been working fine for decades: https://www.nasa.gov/specials/wheels/
You'll also find industrial equipment examples like https://www.sourceproequipment.com.au/crocodile-skid-steer-b...
As the person you're replying to said, though, the problem for passenger cars is NVH. They aren't quiet.
Even with that downside, though, they are still used in consumer-facing applications like some bike sharing programs: https://medium.com/@fredchang/by-now-youve-probably-heard-of...
Where a smoother ride is less significant than unlocking a bike & finding a flat tire.
You'll also find industrial equipment examples like https://www.sourceproequipment.com.au/crocodile-skid-steer-b...
As the person you're replying to said, though, the problem for passenger cars is NVH. They aren't quiet.
Even with that downside, though, they are still used in consumer-facing applications like some bike sharing programs: https://medium.com/@fredchang/by-now-youve-probably-heard-of...
Where a smoother ride is less significant than unlocking a bike & finding a flat tire.
What the hell, I've been looking for something like this for the past few months. Only ones I could find were Tannus (too soft) and Schwalbe (garbage).
Don't care about weight, noise, ride quality, just need unbreakable tires because riding through neighborhoods where people break glass bottles on the bike paths will make me smash someone's head with one someday.
Don't care about weight, noise, ride quality, just need unbreakable tires because riding through neighborhoods where people break glass bottles on the bike paths will make me smash someone's head with one someday.
Panaracer T-Serv Messenger bike tires are what you're looking for. They're lighter than the gatorskins and work incredibly well. I rode one pair until the tread was gone in SF (several years) and never got one flat tire.
https://www.panaracerusa.com/collections/commuter-city/produ...
https://www.panaracerusa.com/collections/commuter-city/produ...
That's a nice option to have, thanks for sharing. I used Gatorskins (Hardshell and the normal version) until the tread was gone the past couple of years. This year I fitted some Continental Grand Prix 4-Season that are holding pretty well against punctures.
Might give these Panaracers a try when the tread of the GP are gone (or if I start getting punctures but so far they are as impervious as the Gatorskins for me).
Might give these Panaracers a try when the tread of the GP are gone (or if I start getting punctures but so far they are as impervious as the Gatorskins for me).
Continental Gatorskin brand tires have worked really well in my experience, easily many thousands of miles. They usually age out (2 years or so) before I've had any flat. I have had snakebite flats though which is usually just due to low air pressure or bad tubes. Tubes can just suck. I've combined them with puncture resistant tubes (thicker tubes) and never had a flat, using 700x25 or 700x28 versions.
https://www.continental-tires.com/bicycle/tires/race-tires/g...
https://www.continental-tires.com/bicycle/tires/race-tires/g...
I was put onto Gatorskins by a friend around ten years ago, and have never looked back. Great tyre with fantastic grip and lifespan.
They are really solid, last forever and are quite light for a non racing tire. They also have decently low rolling resistance when inflated high.
However, in my experience they are really sketchy in wet conditions. I've wiped out or almost did multiple times on gatorskins. Deflating them in wet conditions works but the rolling resistance is then quite high.
I've found that the Schwalbe Marathons in wider sizes (I think I got 38s?) are much more confidence inspiring and comfortable, and makes up for the fact that I have to change a flat twice a year instead of once a year.
However, in my experience they are really sketchy in wet conditions. I've wiped out or almost did multiple times on gatorskins. Deflating them in wet conditions works but the rolling resistance is then quite high.
I've found that the Schwalbe Marathons in wider sizes (I think I got 38s?) are much more confidence inspiring and comfortable, and makes up for the fact that I have to change a flat twice a year instead of once a year.
Oh yeah, I've had some extremely solid wipeouts in the wet on mine, but then again I usually just attribute that more to me being a hooligan on the bike more than the tires :P
My Marathons are nice and fast, but slippery on the curves and I'd watch out in the rain
How about just regular Schwalbe Marathons Plus? In my experience those tyres are literally unpuncturable(at the cost of a huge weight penalty).
I rode across the country on a pair (two pairs actually, first set wore out) of marathon pluses. I got 1 flat from a metal staple, which is pretty good for 4200 miles :D
These are great tires, but the rolling resistance can absolutely be felt. They do suffer in grip in wet conditions as well.
The non-Plus Marathons are quite nice, but less puncture-proof.
You can't really win, the stiffer the tire the better it is at protecting the tube but the rolling resistance is higher and the tire flexes less which makes it less grippy.
You can't really win, the stiffer the tire the better it is at protecting the tube but the rolling resistance is higher and the tire flexes less which makes it less grippy.
Weirdly, it's actual black magic - the regular Marathons have the lowest rolling resistance of any touring tyre[0](lower than Schwalbe's own Marathon Racer lol), despite being very good at puncture proofing and not being completely slick. No idea how Schwalbe has actually done it.
[0] https://www.bicyclerollingresistance.com/tour-reviews/schwal...
[0] https://www.bicyclerollingresistance.com/tour-reviews/schwal...
> Schwalbe (garbage).
I have never read these two words in the same sentence. I've put thousands upon thousands of miles on my Schwalbe Marathons with nary a flat. Granted, nothing is 100%, but I find Schwalbe's a solid urban/touring choice.
I have never read these two words in the same sentence. I've put thousands upon thousands of miles on my Schwalbe Marathons with nary a flat. Granted, nothing is 100%, but I find Schwalbe's a solid urban/touring choice.
same experience here. 'Schwalbe Marathon Plus' are the only pneumatic tires I have used on a wheelchair that last more than a few weeks of hard abuse.
Tannus too soft? I've had mine for a year and a summer, and really couldn't be happier. If anything, I find them a tad on the hard side.
This is an ordinary, oldfashioned pushbike with medium-width tyres.
I was regularly getting flats with a new to me road bike.
I switched to Continental Grand Prix 4 Season and haven't had a flat in 2 years in Portland, OR (though my frequency is down with the pandemic).
I switched to Continental Grand Prix 4 Season and haven't had a flat in 2 years in Portland, OR (though my frequency is down with the pandemic).
Schwalbe Marathon Mondial are incredibly durable tyres. Never had a single flat in at least 20,000 km on them.
A lot of heavy equipment drives around with water-filled tires, so it's already there. Definitely not what you meant though.
Hmm, why water filled? I can't think of any advantages, but can think of downsides such as a massive increase in unsprung weight.
Ballast for increased traction and tipping capacity with the positive side effect of lower COG.
Ah! That's a good idea.
The only springs on most tractors - ancient or modern - are between the seat and the frame to which it is affixed. IOW the vast majority of the tractor's total weight is unsprung.
Its easier to let the water out of a tractor tire than to take a 500lb wheel plate off...when changing a tire.
...added weight is for better traction. Almost all 2WD tractors will have their back tires filled with a water/radiator fluid mixture (ice doesn't work well if you want to keep the tire on the rim).
...added weight is for better traction. Almost all 2WD tractors will have their back tires filled with a water/radiator fluid mixture (ice doesn't work well if you want to keep the tire on the rim).
Water's basically incompressible, if some Michael Crichton book I read like 25 years ago is to be believed.
My guess would be one or more of: the above; greater heat capacity; or, something to do with surface area vs. volume meaning that at a large enough size water in a tire is far lower-pressure and easier to contain than air at a high enough pressure to keep it inflated, and/or, relatedly, something to do with heat dissipation from compressing gasses being really hard to deal with once you hit a certain surface-to-volume ratio.
[EDIT] LOL, guess all these were wrong and it's just for the extra weight.
My guess would be one or more of: the above; greater heat capacity; or, something to do with surface area vs. volume meaning that at a large enough size water in a tire is far lower-pressure and easier to contain than air at a high enough pressure to keep it inflated, and/or, relatedly, something to do with heat dissipation from compressing gasses being really hard to deal with once you hit a certain surface-to-volume ratio.
[EDIT] LOL, guess all these were wrong and it's just for the extra weight.
The book was Sphere. It rocked. I too remember this fact just from that.
which was made into a movie
https://en.m.wikipedia.org/wiki/Sphere_(1998_film)
that is confusingly similar to The Abyss,
https://en.m.wikipedia.org/wiki/The_Abyss
I always get the two confused.
https://en.m.wikipedia.org/wiki/Sphere_(1998_film)
that is confusingly similar to The Abyss,
https://en.m.wikipedia.org/wiki/The_Abyss
I always get the two confused.
https://tractoraddict.com/tractor-tires-filled-with-water/
Beet juice is interesting! lol
Beet juice is interesting! lol
It's a lot better than the calcium chloride that they used to use, when a telehandler blew out a tire and drained hundreds of pounds of saltwater into my parents' lawn a few years ago it did a lot of damage.
Beet juice is soooooooo much better for the environment than the salts it is replacing. Unfortunately it is slightly more expensive so we get to continue poisoning our waterways with salts.
Sounds like it’s used as ballast: https://tractoraddict.com/tractor-tires-filled-with-water/
The only time they move fast enough to worry about unspung weight is when they are on a trailer.
That isn't strictly true, but in general such equipment spends most of it time moving very slowly it it moves at all. Transports speeds do become a problem, but that is only done for a short time (or you have it on a trailer so you can go faster) so nobody worries about the issue.
That isn't strictly true, but in general such equipment spends most of it time moving very slowly it it moves at all. Transports speeds do become a problem, but that is only done for a short time (or you have it on a trailer so you can go faster) so nobody worries about the issue.
Nothing is sprung on a wheel loader or a scaper.
A disadvantage is that only the rubber absorbs impacts, since the fluid is incompressible for all intents and purposes.
The tyre is only partially filled (for example 40%) with water - so the tyre is not “incompressible”. https://salesmanual.deere.com/sales/salesmanual/en_NA/tracto...
I see. Furthermore, there is an admonishment:
IMPORTANT: Never fill any tire to more than 90% full. More solution could damage tire.
IMPORTANT: Never fill any tire to more than 90% full. More solution could damage tire.
... but for 'intensive purposes' on the other hand the story is less clear
Sometimes foam is used rather than water.
Also trains drive around with solid metal tires.
Trains have the benefit of exceptionally smooth "roads"
At some point they will be viable... whether this is that point or not is yet to be seen.
> At some point they will be viable
Why do you assume this?
Why do you assume this?
Because at some point we used wood for wheels?
How does wood --> inflated rubber imply inflated rubber--> airless rubber? I don't see any logic in that.
We still do use wood for wheels... So...
Because this is primarily a materials science problem, and we are still novices at materials science.
There does not have to exist a solid material with the properties of a gas.
What? I don't understand what you mean by that.
There's no reason to assume this is a solvable problem, just because it's a new field. I remember when cold fusion was considered inevitable.
You don't actually have any reason to assume it will happen other than blind optimism.
You don't actually have any reason to assume it will happen other than blind optimism.
... you don't actually have any reason to assume it won't happen other than blind pessimism. So let's just agree to disagree.
I love to disagree because I'm a betting man. Want to wager some money on a bet? Pick a timeline (5 years, 10 years, 20 years, 50 years) and maybe we can make this fun!
lol. No bet. Not because I doubt my position (I see an aerogel-inspired material working out). Rather because the 50 year timeline that I would feel safe betting on is basically my end-of-life. I'm not really interested in paying out a longbets.org payment on my deathbed.
As he said, more or less. Sorry for being cryptic.
"There's no reason to assume this is a solvable problem"
"There's no reason to assume this is a solvable problem"
I use nitro oxygen in my tyres. Pressure problems are gone.
The Earth's atmosphere is about 80% nitrogen and a little less than 20% oxygen, with some carbon dioxide, argon, variable amounts of water vapor, and some pollution.
What's "nitro oxygen", then?
What's "nitro oxygen", then?
My guess is parent comment misspoke and meant pure nitrogen -- which does indeed help with tire pressure. The ideal gas law still applies, so there will be seasonal changes in pressure, but there will be much less exfiltration (via 'permeation', specifically) of gas through the material (N2 has a larger 'kinetic diameter' than O2; O2 will permeate 3-4x faster through rubber than N2).
So if regular air is 80% nitrogen already, won't the tires move towards 100% nitrogen with each top off since the tires will be retaining the nitrogen more than the oxygen? Sounds like a marketing trick unless they're filling newly mounted tires with 100% nitrogen.
That's a pretty clever thought in general, but yours is only a first approximation.
First, permeation decreases with pressure, at different rates for the two gases. If you consider only this fact you will find that the partial pressures of O2 and N2 asymptotically approach homeostasis, rather than simply all the O2 leaving and all the N2 remaining.
Second, permeability changes with temperature, so the ratio of O2 and N2 exfiltration rate changes seasonally, as each gas has a different permeability-vs-temperature curve. Third, the ideal gas law causes pressure changes seasonally which will also decrease exfiltration in winter, and once again, each gas will have its own permeability-vs-pressure curve, so these become very confounding factors.
All in all, the reality of the situation is that filling up your tires with atmospheric air will probably settle on partial pressure ratios of, say, 85/15 rather than 100/0. The deflation that you get comes from only about 5% of the O2 leaving the tire; and of course you get another big deflation when the weather first turns cold.
I don't know the exact numbers because I've frankly never thought to look into this before. So like I said, it was a clever thought! But it needed to be taken a few steps further.
First, permeation decreases with pressure, at different rates for the two gases. If you consider only this fact you will find that the partial pressures of O2 and N2 asymptotically approach homeostasis, rather than simply all the O2 leaving and all the N2 remaining.
Second, permeability changes with temperature, so the ratio of O2 and N2 exfiltration rate changes seasonally, as each gas has a different permeability-vs-temperature curve. Third, the ideal gas law causes pressure changes seasonally which will also decrease exfiltration in winter, and once again, each gas will have its own permeability-vs-pressure curve, so these become very confounding factors.
All in all, the reality of the situation is that filling up your tires with atmospheric air will probably settle on partial pressure ratios of, say, 85/15 rather than 100/0. The deflation that you get comes from only about 5% of the O2 leaving the tire; and of course you get another big deflation when the weather first turns cold.
I don't know the exact numbers because I've frankly never thought to look into this before. So like I said, it was a clever thought! But it needed to be taken a few steps further.
Thanks! I love getting answers like this from the community.
Maybe just nitrogen? Costco inflates tyres with nitrogen. The pair of tyres on my vehicle inflated with nitrogen don’t seem to lose pressure, the other two need topping up occasionally.
That's the point. He's being sarcastic and calling "atmospheric air" "nitro oxygen"
I imagine it's a joke on people that use nitrogen.
https://www.tireamerica.com/resource/nitrogen-vs-oxygen-for-...
That at least helps with some of the logic. However, doesn't directly answer what "nitro oxygen" is. Guessing some sort of slang. It's definitely not a scientific phrase. Nitrogen oxide or something maybe too much for grease monkies so they call it nitro oxygen??? just guessing.
That at least helps with some of the logic. However, doesn't directly answer what "nitro oxygen" is. Guessing some sort of slang. It's definitely not a scientific phrase. Nitrogen oxide or something maybe too much for grease monkies so they call it nitro oxygen??? just guessing.
Maybe the noise they generate is good for EVs which are dangerously quiet for pedestrians?
Valid point, although pedestrian safety is mostly discussed in the low-to-mid-speed regime (<= 45 MPH), while tire noise (at least according to my own observation) dominates in the high speed regime (>= 65 MPH). There might be some overlap though.
Also worth pointing out: NVH is not just Noise --- it includes Vibration and Harshness that are only felt by the people inside the vehicle.
Also worth pointing out: NVH is not just Noise --- it includes Vibration and Harshness that are only felt by the people inside the vehicle.
And effective at rattling off any untorqued/loose nuts/bolts.
You can ear an EV very well, the rolling noise and the wind noise is difficult to miss. Of course if the EV is driven very slowly it's not noisy unless it has a fake sound like many does, but it's not very dangerous either.
Ironically NVH is even more important in EVs since the engine noise no longer drowns out unpleasant sounds like fan motors, hums, squeaks/rattles
Every EV sold today must make noise at low speeds.[1]
1. https://en.wikipedia.org/wiki/Electric_vehicle_warning_sound...
1. https://en.wikipedia.org/wiki/Electric_vehicle_warning_sound...
Some EVs have mandatory sound emitters to not be fully silent (and thus dangerous). I thought it was weird harmonics from the synRM engine but it's synthetic and enforced by regulations.
Hybrids as well. The Toyota Prius has had this at low velocities since before EV cars were mass produced (I believe Toyota uses a speaker that makes a sort of sci fi sound). It is a legal requirement to generate a minimum amount of noise to sell a car in some countries.
I thought it was a plastic valence rubbing on something.
nah it's on purpose https://www.youtube.com/watch?v=mNkGD_Sryxg
Noise is not good, ever.
Don't get me wrong - I'd expect Michelin to have done some testing to see NVH is within tolerance levels right?
Airless is really close to working for bikes. If I were commuting on a bike now I'd be comfortable going for it. The downsides - painfully hard installation, uphill resistance, ...etc. - will be worth it.
Airless is really close to working for bikes. If I were commuting on a bike now I'd be comfortable going for it. The downsides - painfully hard installation, uphill resistance, ...etc. - will be worth it.
I also want to add, since this is more of a deep auto-industry thing, that NVH testing is almost like longitudinal health studies. NVH engineers actually have charts of which specific frequencies our internal organs resonate at. For a layperson it's easy to imagine that NVH testing is just a matter of setting up a dB meter and some accelerometers to make sure things aren't bouncing around too much, but it's actually much more nuanced than that, and the engineers have to consider the long-term effects of driving in the vehicle.
One easy way to picture this is: recall your last long road trip, or airplane flight, anything more than 3 hours or so. You get so tired after those, especially considering that you've only just sat still for a few hours. But in actuality your body is making hundreds of tiny corrections to posture each minute, in response to the vibrations of the vehicle, and that literally exhausts your muscles and nervous system. Now imagine that you make that car "5% more harsh" and redo the road trip; you will feel the compound effects of that additional harshness. Auto manufacturers take NVH very seriously, because it turns out to be a pretty big deal.
My point is that even if NVH comes back OK in the lab, they still will need a good deal of real world data with test subjects representative of the 'average driver' before they can make a determination.
Edit to add: I know of at least one case where the entire drivetrain of a vehicle was redesigned due to NVH.
One easy way to picture this is: recall your last long road trip, or airplane flight, anything more than 3 hours or so. You get so tired after those, especially considering that you've only just sat still for a few hours. But in actuality your body is making hundreds of tiny corrections to posture each minute, in response to the vibrations of the vehicle, and that literally exhausts your muscles and nervous system. Now imagine that you make that car "5% more harsh" and redo the road trip; you will feel the compound effects of that additional harshness. Auto manufacturers take NVH very seriously, because it turns out to be a pretty big deal.
My point is that even if NVH comes back OK in the lab, they still will need a good deal of real world data with test subjects representative of the 'average driver' before they can make a determination.
Edit to add: I know of at least one case where the entire drivetrain of a vehicle was redesigned due to NVH.
And this stuff is exactly why it's a million times less fatiguing to drive a vehicle from 2020 over one from 1990, even if you control for almost every other variable by picking one that has changed minimally (i.e. a few panel vans and many medium duty trucks)
That's a wild over exaggeration.
That certainly puts an interesting spin on the one time I had to ride the back of a bus from west coast to east coast. It was three days and I was physically and mentally exhausted at the end despite sleeping for a fair chunk of it.
Edit to add: Thanks for your input on this, it's insightful and interesting!
Edit to add: Thanks for your input on this, it's insightful and interesting!
A friend recommended I wear earplugs on plane flights, for a similar reason. He said that the constant noise stresses our bodies/minds, and lowering it makes the time more pleasant. It may entirely be placebo effect, but I find it very helpful.
Thanks for this. Is there a way to look up NVH values for current tires? I'm assuming some have better NVH values than others and they could have an effect on making the drive feel nicer.
This was very cool to read; thanks for such an informative comment.
I imagine this will sound naive, but I wonder why this sort of vibration can't be addressed with shock absorbers in the seats?
I imagine this will sound naive, but I wonder why this sort of vibration can't be addressed with shock absorbers in the seats?
> I wonder why this sort of vibration can't be addressed with shock absorbers in the seats?
Not at all naive, because it is addressed with shock absorbers in the seats; that is one of the very many tools NVH engineers use. :) But they're not 'shock absorbers' in the way you're thinking; the actual foams used in the car seats are specifically designed and selected to dampen certain frequencies. But, kind of like a speaker or headphones or even ear plugs, the dampening happens over a spectrum, and in general our organs resonate at lower frequencies, which are harder for foamlike materials to dampen.
NVH engineers view the entire road-vehicle-driver system as a huge, complex, spring-mass-damper system, and do a whole ton of partial differential equations to solve for the outputs.
Edit to add: so why not use traditional 'shock absorbers', the spring-damper kind that you're used to seeing? For passenger vehicles the answer is weight and complexity. But many trucks and tractors and so on do in fact have these.
Not at all naive, because it is addressed with shock absorbers in the seats; that is one of the very many tools NVH engineers use. :) But they're not 'shock absorbers' in the way you're thinking; the actual foams used in the car seats are specifically designed and selected to dampen certain frequencies. But, kind of like a speaker or headphones or even ear plugs, the dampening happens over a spectrum, and in general our organs resonate at lower frequencies, which are harder for foamlike materials to dampen.
NVH engineers view the entire road-vehicle-driver system as a huge, complex, spring-mass-damper system, and do a whole ton of partial differential equations to solve for the outputs.
Edit to add: so why not use traditional 'shock absorbers', the spring-damper kind that you're used to seeing? For passenger vehicles the answer is weight and complexity. But many trucks and tractors and so on do in fact have these.
Fascinating, thanks for the response.
Really? There are small cans of spray which you can have easily with you. Got a flat? Look where, pull it out. Spray the foam in. Turn the wheel for a minute, look for overseen leaks, maybe, and pull stuff out of them. Turn wheel a few more times. Pump. Or use car-adapter for pump at gas station. Those stuff costs between 2 and 4€ for a can of sprayfoam, and maybe 50ct for a small adapter(sugar cube like, but cylindrical). Given the stuff Schwalbe and Continental are offering for normal bicycles, I don't get all the rage. Because a flat fixed like described above lasts about half a year, then the profile is too slick, and I change tire and tube.
Works for me. Feels comfortable and fast. Is economic.
YMMV.
Works for me. Feels comfortable and fast. Is economic.
YMMV.
You make it sound simple. It's not when I'm commuting. Even to use the sprayfoam sealers - I need to first identify the puncture and that's not always obvious. I've usually just changed the entire tube.
It's my experience. In case of unidentified punctures the foam leaks out (of them), and then you can remove the splinter, or whatever by hand, maybe with a paper tissue, or tweezers from your swiss officers knife, some multitool. Dunno. I don't have that many flats. About 5 or 6 since 2005? Each one maybe a 10 to 15 minute break.
edit: Thinking about it, one could even omit the spray can because in cities there's almost always a gas station near, which is stocking that stuff. So only the small adapter would be necessary, if your valves aren't like the ones for cars anyways. I didn't do that so far because I'm often bicycling out of the city, instead of into it.
edit: Thinking about it, one could even omit the spray can because in cities there's almost always a gas station near, which is stocking that stuff. So only the small adapter would be necessary, if your valves aren't like the ones for cars anyways. I didn't do that so far because I'm often bicycling out of the city, instead of into it.
The last flat I had involved a 3" split in the tube - ain't no slime/foam/spray can that's gonna fix that.
I just used aramid fiber lining on the inside of my Vee Rubber tires (best stuff, fuck Conti and Schwalbe), haven't had a flat yet. Better than "puncture proof" shit from Conti.
But it's probably just a matter of time before an exotically shaped piece of glass gets through :D
But it's probably just a matter of time before an exotically shaped piece of glass gets through :D
Bridgestone said bike tweels were close 4 years ago, and then again 2 years ago... I won't hold my breath! :)
Tannus is the leader right now. I have tried it and I'm fairly comfortable. Again, the number of flats you get in some of the cities in the Bay Area is insane. That makes it worth it.
Michelin is by far the market leader in tires, especially compared to Bridgestone.
EVs are quite heavy for their footprint due to the weight of the batteries.
There are exceptions though like the upcoming Aptera which only weighs around 800 kg even with a large range.
I'll believe it when it happens. Aptera has gone out of business more times than they have released a production car.
I remember being excited about the Aptera twelve years ago. I’ll maybe get excited again once they actually start shipping a vehicle. They’ve already gone out of business once.
Unfortunately, they are also making a lot of claims that they haven't demonstrated in a working vehicle yet. Getting to production is going to be hard.
This will change with improved batteries, charging infrastructure, and shrinking EV tech. By the time this could hit the market, hopefully the weight difference would be less stark.
[deleted]
EVs are usually much heavier than gas cars.
I don't think that's true anymore. For example, the Tesla Model 3 weighs anywhere from 3,552-4,072lbs depending on the trim level.[1] (The heaviest is the Model 3 Performance which has the biggest battery, motors, and wheels.) The BMW 3 series is 3,582-4,138lbs depending on the exact model and trim.[2]
Gas cars don't have big heavy batteries but they do have big heavy engine blocks and more complicated (heavier) drivetrains.
1. https://en.wikipedia.org/wiki/Tesla_Model_3
2. https://www.caranddriver.com/bmw/3-series/specs
Gas cars don't have big heavy batteries but they do have big heavy engine blocks and more complicated (heavier) drivetrains.
1. https://en.wikipedia.org/wiki/Tesla_Model_3
2. https://www.caranddriver.com/bmw/3-series/specs
BMW is a particularly heavy sedan. The Honda Civic is 2877 to 3126. Even the Golf R which has a rear diff, DCT, and a 2.0 turbo is only 3100 pounds.
I picked a gas car of comparable size. The Civic and Golf are much smaller than the Model 3.
The Civic is 2 inches shorter and 2 inches narrower than the Model 3, but it actually has a larger interior volume by one cubic foot.
Size up to the Accord which is 8 inches longer and a half inch wider than a Model 3 (and 9ft^3 more interior space), and it still only weighs 3131-3362 lbs.
Size up to the Accord which is 8 inches longer and a half inch wider than a Model 3 (and 9ft^3 more interior space), and it still only weighs 3131-3362 lbs.
Where are you getting those figures? When I look up the stats for the 2021 Accord I see weights ranging from 3,150-3,446lbs.[1]
Really though, the Civic and Accord aren't competing with the Model 3. They're front wheel drive. They have less power and torque. They use struts for the front suspension. All of these measures save significant weight (and cost). That's why I picked the BMW 3 series. It's similar size, performance, and cost. If we look at other competitors to the Model 3 we get similar weights:
- Volvo S60: 3,724-4,468lbs. (The low number is front wheel drive. The high number is a plug-in hybrid.)
- Audi A4: 3,682-3,726lbs.
- Mercedes C-Class: 3,472-3,605lbs.
- Cadillac CT4: 3,422-3,616lbs.
- Volkswagen Passat: 3,014–3,794lbs. (The lighter versions are front wheel drive only. The heavier versions are hybrids.)
In general, fancier cars are heavier. Also safer cars tend to be heavier. Yes batteries are heavy, but so are engines, drivetrains, starter motors, turbochargers, exhaust systems, fuel tanks, and so on. Early electric cars were significantly heavier because they were based on combustion platforms. When EVs are designed from the ground up, the weight penalty is less than 10%. Vehicle models in the same market segment vary more than that, and some combustion vehicles are already heavier than their electric competitors. This will likely get better with time as battery technology improves.
The statement "EVs are heavier" is approximately as true as "AWD vehicles are heavier". All else equal it's more likely than not, but the difference is rarely enough to matter for any practical purpose.
1. https://www.caranddriver.com/honda/accord/specs/2021/honda_a...
Really though, the Civic and Accord aren't competing with the Model 3. They're front wheel drive. They have less power and torque. They use struts for the front suspension. All of these measures save significant weight (and cost). That's why I picked the BMW 3 series. It's similar size, performance, and cost. If we look at other competitors to the Model 3 we get similar weights:
- Volvo S60: 3,724-4,468lbs. (The low number is front wheel drive. The high number is a plug-in hybrid.)
- Audi A4: 3,682-3,726lbs.
- Mercedes C-Class: 3,472-3,605lbs.
- Cadillac CT4: 3,422-3,616lbs.
- Volkswagen Passat: 3,014–3,794lbs. (The lighter versions are front wheel drive only. The heavier versions are hybrids.)
In general, fancier cars are heavier. Also safer cars tend to be heavier. Yes batteries are heavy, but so are engines, drivetrains, starter motors, turbochargers, exhaust systems, fuel tanks, and so on. Early electric cars were significantly heavier because they were based on combustion platforms. When EVs are designed from the ground up, the weight penalty is less than 10%. Vehicle models in the same market segment vary more than that, and some combustion vehicles are already heavier than their electric competitors. This will likely get better with time as battery technology improves.
The statement "EVs are heavier" is approximately as true as "AWD vehicles are heavier". All else equal it's more likely than not, but the difference is rarely enough to matter for any practical purpose.
1. https://www.caranddriver.com/honda/accord/specs/2021/honda_a...
And the GMC Yukon is 5500-5800 lbs, which is what I expect the original comment to be making a comparison with.
GMC Sierra, maybe, but as far as SUVs go, the Yukon/Escalade/Suburban/Tahoe are not a very popular size of SUV in the US. They're too dang expensive for most people.
The RAV4, CR-V, and Rogue are the top 3 best selling SUVs in the US so far this year. They're about half the price of a Yukon. The rest of the top 25 are almost all sedans, similarly sized midsize SUVs and pickups.
The RAV4, CR-V, and Rogue are the top 3 best selling SUVs in the US so far this year. They're about half the price of a Yukon. The rest of the top 25 are almost all sedans, similarly sized midsize SUVs and pickups.
The 3 has at least 5 cubic feet more in cargo space than the Civic. In practice there is a pretty big difference between those two cars.
The Civic and 3 both have 15 ft^3 of cargo space according to the EPA.
Regardless, the Accord dwarfs it and supports the above point that the Model 3 is a heavy car, and the BMW 3 series is heavy because it was built to have a premium feel as a design priority, not because it is ICE.
Regardless, the Accord dwarfs it and supports the above point that the Model 3 is a heavy car, and the BMW 3 series is heavy because it was built to have a premium feel as a design priority, not because it is ICE.
That's odd, I had no idea the EPA even presented a spec like that. It must be a difference in how they estimate it.
The BMW comparison is interesting as the performance numbers are similar. The 3 series heft vs a civic is largely due to the engine and drivetrain choices. Its much easier to optimize weight on a low powered FWD car.
The BMW comparison is interesting as the performance numbers are similar. The 3 series heft vs a civic is largely due to the engine and drivetrain choices. Its much easier to optimize weight on a low powered FWD car.
And an e-Golf weighs 3455lbs. Which - sure, is 10% heavier than a Golf R. But then so, apparently, is a heavy Civic compared to a light one.
For the same form factor, yes that's true.
Last time I tried estimating; EV's are about 25% heavier. Improvements in battery energy density will probably erase that inside 5-10 years.
Sorry for the conversation pivot, but this attitude sucks and is terrible for climate change and was decided wholesale by suppliers. While SUVs are leading sales in the US, it was the decision by car manufacturers to discontinue sales of anything other than SUVs in the US. That you say, "well these wheels which would reduce waste aren't useful for Americans," they are partly not useful because the car industry here pushed through advertising pressure (and yes, due to demand in part) for that outcome, it's a coupled two way street. So, that same industry bears some of the blame.
Nah...americans like big cars and manufacturers followed the sales! Even worse, europeans started to like big cars too...I just don't get why people like to drive big SUVs in the city.
> europeans started to like big cars too
I saw a documentary on this once where they interviewed some psych guy who was advising the car industry. He said that it took him some time to convince them to make everything ridiculously big. Not just the car, but the lights etc. It was based on his theory that when we first see something we evaluate it using the bit of our brain that has been there since we were lizards. And that bit is impressed by size. His theory was that it overrides everything. Most people will pick the bigger thing. He was right.
I saw a documentary on this once where they interviewed some psych guy who was advising the car industry. He said that it took him some time to convince them to make everything ridiculously big. Not just the car, but the lights etc. It was based on his theory that when we first see something we evaluate it using the bit of our brain that has been there since we were lizards. And that bit is impressed by size. His theory was that it overrides everything. Most people will pick the bigger thing. He was right.
> His theory was that it overrides everything. Most people will pick the bigger thing. He was right.
Wouldn't that mean that most people---regardless of culture, education, etc.---would pick SUV over sedans? Is that true?
Granted there are plenty of SUVs in the US, but as far as I can see on the road and parking lots, sedans are still quite popular. I even see a lot of Minis and Beetles, which are even smaller than a regular sedan.
Wouldn't that mean that most people---regardless of culture, education, etc.---would pick SUV over sedans? Is that true?
Granted there are plenty of SUVs in the US, but as far as I can see on the road and parking lots, sedans are still quite popular. I even see a lot of Minis and Beetles, which are even smaller than a regular sedan.
Yeah the role of marketing in influencing public opinion should not be discounted.
That was public opinion influencing marketing.
I mean the public relations industry is all about a few people having an idea and figuring out how to convince lots of people. Just look at how cigarette sales to women were pushed with intentional ad campaigns to change public opinion. They of course need to craft their message in a way that appeals to their audience (for example calling cigarettes "torches of freedom" to appeal to progressive women in the 1920's) but the message "buy cigarettes" is decided by the marketer.
https://yourstory.com/2014/08/torches-of-freedom/
https://yourstory.com/2014/08/torches-of-freedom/
I'm not trying to defend myself or anything since I don't even have a car, but when I did, it was always an SUV. It wasn't so much a matter of preference as necessity. I'm not exactly huge, only 6'2", but if I try to drive my wife's GTI, I'm hunched over and hitting my head on the ceiling. Only way to do it is leaning severely back with the seat reclined. Trying to be a backseat passenger in an average sedan is completely impossible. Even though it's at least possible to drive a car like that, if not comfortably, it definitely isn't safe, since visibility is shot to shit with the tiny mirrors and your head and elbows running into something every time you try to turn to cover your blind spots.
Contrast that with an SUV. No need to lean or hunch. You can see everything without trouble. You can move without trouble. It's actually possible to use the backseat.
Contrast that with an SUV. No need to lean or hunch. You can see everything without trouble. You can move without trouble. It's actually possible to use the backseat.
What? I'm about the same height and drive a sedan just fine, and it's comfortable and safe. I don't know how small your wife's car is, but I've never been in one so small that I'm bumping my head in the ceiling, that would be weird.
GP is probably proportioned like Michael Phelps: short legs, long torso.
I'm of a similar height, but oppositely proportioned, and the driver's seat in most cars doesn't go back far enough that my lower thighs rest on the seat, which makes for a lot of butt discomfort on long trips.
If the seat does go back far enough for my legs to be comfortable, it's almost unavoidable that the steering wheel is uncomfortably far away, and I put the seat pretty close to bolt upright to put my shoulders closer and reduce the impression that I'm hanging on to the wheel for dear life as it's trying to pull away from me.
Bicycles are similarly problematic: I want a shorter top tube than is common for my nominal frame size, so I ride a 59cm road bike frame with a short stem and a lot of seatpost showing. You'd be more likely to find somebody with my inseam (34" [0]) on a 61cm or 63cm frame.
[0] Sorry for the mixed units. I'm giving them in the trade sizes. Road bikes are sized in metric, and pants are sized in inches, at least in the US.
I'm of a similar height, but oppositely proportioned, and the driver's seat in most cars doesn't go back far enough that my lower thighs rest on the seat, which makes for a lot of butt discomfort on long trips.
If the seat does go back far enough for my legs to be comfortable, it's almost unavoidable that the steering wheel is uncomfortably far away, and I put the seat pretty close to bolt upright to put my shoulders closer and reduce the impression that I'm hanging on to the wheel for dear life as it's trying to pull away from me.
Bicycles are similarly problematic: I want a shorter top tube than is common for my nominal frame size, so I ride a 59cm road bike frame with a short stem and a lot of seatpost showing. You'd be more likely to find somebody with my inseam (34" [0]) on a 61cm or 63cm frame.
[0] Sorry for the mixed units. I'm giving them in the trade sizes. Road bikes are sized in metric, and pants are sized in inches, at least in the US.
I'm an inch or so taller than you and have driven a GTI, along with other small cars, very comfortably for more than 10 years.
Clearly this is a situation where, quite literally, YMMV.
Clearly this is a situation where, quite literally, YMMV.
Have a look at the current model Honda Accord. It's a midsize car, but the engineers have somehow managed to create an extremely roomy cabin. 6'4" people can comfortably sit in the rear seats.
The interior space of an MPV is typically bigger than an SUV.
Considering the sales numbers of MPVs, it would seem that the argument you make is not what is pushing the disproportionate commercial success of SUVs.
Considering the sales numbers of MPVs, it would seem that the argument you make is not what is pushing the disproportionate commercial success of SUVs.
This problem with sedans sounds so surreal to me.
I'm 6'4" and my car is 2005 Toyota Yaris hatchback. And that cars feels comfortable without any special adjustments.
This is why regulation is needed. States do not allow any kind of car on the streets. But often car manufacturers say it will threaten economy and labor.
There’s some truth to that – remember the surveys where parents said that they could imagine driving an SUV but not a minivan if they divorced & were dating again? – but they were also subsidized. If the price of gas wasn’t artificially low, or they had to meet the same safety and pollution standards as everything else, they’d be less popular. We did at least close the Hummer tax write-off, but we should be doing more on the safety front since SUV drivers reversed a decades-long run of fatality reductions.
It doesn't work like that anymore.
99% of the "SUVs" you see today are CUVs, which in turn are barely more than a lifted sedan.
So the difference is gas milage is miniscule, to the point gas prices will no longer affect the sales of the most successful SUVs
99% of the "SUVs" you see today are CUVs, which in turn are barely more than a lifted sedan.
So the difference is gas milage is miniscule, to the point gas prices will no longer affect the sales of the most successful SUVs
I used to drive a sedan and it felt like I was dropping down on entry and climbing out on exit. Along came kids and I've been driving a mini-van instead ever since.
One thing I really like about the van (Honda Odyssey) is that you step slightly up to enter and step down to exit. Very comfortable. And this is on a car that's so low to the ground (good for little kids and old dogs) that it's like a snow plow if there's more than a few inches of snow.
I want something lifted more than a sedan so I step up to enter and also has more ground clearance for snow, potholes, rough roads, etc. But that doesn't mean 44" tires with a lift kit.
One thing I really like about the van (Honda Odyssey) is that you step slightly up to enter and step down to exit. Very comfortable. And this is on a car that's so low to the ground (good for little kids and old dogs) that it's like a snow plow if there's more than a few inches of snow.
I want something lifted more than a sedan so I step up to enter and also has more ground clearance for snow, potholes, rough roads, etc. But that doesn't mean 44" tires with a lift kit.
Not sure where you live but the popular models around here are the 15mpg types and the drivers are … not driving efficiently so they're unlikely to be reaching that. You will see a few of the higher-MPG models like a RAV4 but at the end of the day it's a physics problem: all of that extra weight, non-aerodynamic design, and over-powered engine add up.
Now, it's true that someone dropping all of the extra cash for one is less price sensitive but we're still talking a pretty big difference going from mileage in the teens to the 40+mpg a decent car gets. High gas prices would get at least some people to reconsider, especially since you have to pay a fair premium as well.
Now, it's true that someone dropping all of the extra cash for one is less price sensitive but we're still talking a pretty big difference going from mileage in the teens to the 40+mpg a decent car gets. High gas prices would get at least some people to reconsider, especially since you have to pay a fair premium as well.
Ignoring for a second that of the top 3 best selling SUVs in the US, the top two share a platform with sedans that weigh nearly the same amount, have the same engine options, and have very similar Cds ...
None of those physics issues are specific to SUVs. Even full size SUVs end up on shared platforms with full size sedans, with "reasonably close" weights (essentially take a well optioned sedan and it weighs around what the base SUV version does)
With the focus on all of these automakers on modular platforms, we've reached the point where even the largest SUVs could meet the exact same standards their sedan counterparts do and not really change at all.
None of those physics issues are specific to SUVs. Even full size SUVs end up on shared platforms with full size sedans, with "reasonably close" weights (essentially take a well optioned sedan and it weighs around what the base SUV version does)
With the focus on all of these automakers on modular platforms, we've reached the point where even the largest SUVs could meet the exact same standards their sedan counterparts do and not really change at all.
Nah. SUVs above a certain weight pay less taxes [0], that's why automakers aggressively marketed them for decades and finally managed to convince Americans that SUVs are cool.
[0]: https://www.irs.gov/publications/p946
[0]: https://www.irs.gov/publications/p946
The vast majority of people don't commercially depreciate their vehicles, so while this does apply to some, it's a relatively small group.
In my huge group of friends, I know one person who does this with his truck, and he readily admits that it involves lying to the IRS and it fraud. Everyone else with a big SUV just prefers them to minivans.
In my huge group of friends, I know one person who does this with his truck, and he readily admits that it involves lying to the IRS and it fraud. Everyone else with a big SUV just prefers them to minivans.
There is also a gas guzzler tax that only applies to cars. If it was applied evenly, most trucks and SUVs would be paying a tax penalty for poor mileage. So there is a kind of indirect government subsidy to bigger vehicles. It is a dumb policy, but it's not why people like SUVs.
"Like" is a strong word.
On the one side you've got the tragedy of the commons that is big vehicles are less safe for other people to be around unless they two are in a big vehicle.
On the other side, Tesla, Toyota, Honda, and Nissan still all have relatively strong sales of sedans in the US. The US market decided that sedans were best from "imports" decades ago and GM/Ford just gave up trying to compete. Then there's of course Tesla telling GM/Ford exactly where the hockey puck was going if they wanted to compete with "imports".
On the one side you've got the tragedy of the commons that is big vehicles are less safe for other people to be around unless they two are in a big vehicle.
On the other side, Tesla, Toyota, Honda, and Nissan still all have relatively strong sales of sedans in the US. The US market decided that sedans were best from "imports" decades ago and GM/Ford just gave up trying to compete. Then there's of course Tesla telling GM/Ford exactly where the hockey puck was going if they wanted to compete with "imports".
While SUVs are leading sales in the US, it was the decision by car manufacturers to discontinue sales of anything other than SUVs in the US
?? Cars are available for sale in the US.
https://www.statista.com/statistics/199981/us-car-and-truck-...
?? Cars are available for sale in the US.
https://www.statista.com/statistics/199981/us-car-and-truck-...
Do you think something like this would be made available for motorcycle tires? Motorcycles are significantly more vulnerable to tire-caused crashes because a motorcycle whose one tire violently decompresses on a highway or autobahn is very likely to have a crash since it can no longer balance, while a car that loses a tire still has 3 other tires and will still have plenty of traction and balance left to pull over. Something like this that makes violent decompression impossible would be a fairly big improvement to motorcycle safety.
I wonder this myself. I'm not sure the technology is ready for street bike speeds, but some of the speeds you do on a dirtbike with tight turns and technical terrains.. maybe.
https://www.rockymountainatvmc.com/tires-and-wheels/michelin...
An "equivalent psi" of 13, which is basically what I run my dirtbike at anyway in the New Hampshire forest trails. Although this is slightly different since it replaces the tube not the whole tire.
https://www.rockymountainatvmc.com/tires-and-wheels/michelin...
An "equivalent psi" of 13, which is basically what I run my dirtbike at anyway in the New Hampshire forest trails. Although this is slightly different since it replaces the tube not the whole tire.
I remember Michelin talking about these before but seem to recall that the biggest impediment was cannibalization concerns from existing departments.
Does the focus on NVH imply that the increase of rolling friction over time is negligible compared to the tread lifetime ? Or is that partly of the reason to target lighter vehicles.
The above assumes the spokes(?) become stretched over time it would increase displacement of the center of rotation from the center of mass which if recall is what creates rolling friction.
The above assumes the spokes(?) become stretched over time it would increase displacement of the center of rotation from the center of mass which if recall is what creates rolling friction.
For two tires with equal interior volume, the rolling resistance of a tweel will be much much greater than the rolling resistance of a normal tire.
That said, tweels are typically designed to be much thinner and have much less interior volume than air-filled, in order to close the gap in rolling resistance. So you'd really need to compare a specific model tire against another specific model tweel in tests to know. But my intuition tells me that the rolling resistance will still be worse almost no-matter-what with today's tech.
So that's partly the reason they target lighter vehicles, and that's partly the reason they seem to be marketing around EVs specifically. That extra rolling resistance may be worth a few $s in gas each month vs only a few cents in electricity for the same driving conditions.
That said, tweels are typically designed to be much thinner and have much less interior volume than air-filled, in order to close the gap in rolling resistance. So you'd really need to compare a specific model tire against another specific model tweel in tests to know. But my intuition tells me that the rolling resistance will still be worse almost no-matter-what with today's tech.
So that's partly the reason they target lighter vehicles, and that's partly the reason they seem to be marketing around EVs specifically. That extra rolling resistance may be worth a few $s in gas each month vs only a few cents in electricity for the same driving conditions.
The marketing focuses heavily on reduction in disposed tires as the environmental benefit. If the tire were equal in terms of rolling resistance we'd see them at least mentioning it in the graphics.
I understood this was a tough problem to solve when I swapped my hard-to-inflate scooter tires with some cheap tweels. NVH, even at 15MPH, is real.
For anyone wanting to do this to their electric scooters, dont... until Michelin makes a scooter form-factor wheel I suppose.
For anyone wanting to do this to their electric scooters, dont... until Michelin makes a scooter form-factor wheel I suppose.
I'm interested in how they maintain balance if mud or ice gets in some of the gaps. Are they just shaped so that the dynamics while rolling flex the ribs & tread in such a way as to expel any such contaminants?
Compact EVs aren't "lighter" though, are they? I wonder if it is the inverse of that - heavier compact-style cars with relatively large amounts of sprung weight.
The issue with tweels is generally the unsprung mass, not the sprung mass. In general they will want to install tweels on vehicles with lower unsprung mass, which means smaller form factor (again, in general).
And I should have been a little clearer in my parent post: I'm mentally comparing something like the BMW i3 to something like the BMW X3; the i3 is about 1000 pounds lighter.
And I should have been a little clearer in my parent post: I'm mentally comparing something like the BMW i3 to something like the BMW X3; the i3 is about 1000 pounds lighter.
Also don't you need to change the traditional car suspension system (McPherson struts, wishbones, shock absorbers etc ... ) to even use these tyres ???.
This does still look to be a marketing excercise for now - I see no product availability to market in 6-12 months still.
For utility vehicles on sale now, it seems:
https://tweel.michelinman.com/michelin-tweel-family-of-produ...
https://tweel.michelinman.com/michelin-tweel-family-of-produ...
That product has been out for 5+ years I think (at least). Plenty of airless in low speed / farm type applications.
The real thing here would be high speed (65+) with good ride / noise.
Maybe launch on local fleet delivery vehicles first (ie, neighborhood driving etc) if there were some lighter options there? Service pickup trucks (light?).
The real thing here would be high speed (65+) with good ride / noise.
Maybe launch on local fleet delivery vehicles first (ie, neighborhood driving etc) if there were some lighter options there? Service pickup trucks (light?).
EVs don't have space to store a donut so an airless system that can't deflate would be useful.
That's malarkey. EVs have more than enough space for a donut. If manufacturers choose to not ship one, that's because they can same $$ and weight by not doing so - it's not due to space.
I drive a compact PHEV and there is literally no place to even put a spare, but that may be more because it's a PHEV and so it has to make room for both batteries and engine. I know most compact EVs don't come with spares and many don't even have a well to store one in.
[deleted]
I don't worry about punctures at all, despite living in a country with a shitty roads. What I worry about A LOT is a catastrophic collision of tire with a 90 degree sharp pothole edge, often made by roadworkers before doing point repair, which potentially can destroy tire irreparably. I wonder if these tires are better protected against such impacts, and just looking at them it seems they are - no side walls which are cut in a strong impact. Looking forward to more impact tests of these tires.
Other comments here say that production tires will have sidewalls to protect the spokes and keep out rocks. If so, I'm a bit disappointed since I like the look of the spokes.
Regarding catastrophic collision with sharp edge, I think these tires will be susceptible as well. If it's enough of a bump to "bottom out", it's going to dent the rim.
Also, your comment about potholes reminded me of a time that I was driving with a friend and we hit a pothole and got a flat. My friend was driving and looked a the flat front tire and said "I'm glad I have a spare". I look at the flat back tire and said "Unless you have two, we're still going to need assistance."
Regarding catastrophic collision with sharp edge, I think these tires will be susceptible as well. If it's enough of a bump to "bottom out", it's going to dent the rim.
Also, your comment about potholes reminded me of a time that I was driving with a friend and we hit a pothole and got a flat. My friend was driving and looked a the flat front tire and said "I'm glad I have a spare". I look at the flat back tire and said "Unless you have two, we're still going to need assistance."
> My friend was driving and looked a the flat front tire and said "I'm glad I have a spare". I look at the flat back tire and said "Unless you have two, we're still going to need assistance.
I did this one time. Ran over a pothole and bottomed out. As I'm replacing my front tire I look to my rear tire and see that it's also flat. That wasn't even the cherry on top. At that point I had my front wheel off and tried putting on the spare anyways.
I had a Kia Stinger GT and the GT version has Brembo brakes which have a much larger caliper than the regular version. Well QA at Kia never thought to check if their spare tire actually fits with the larger caliper. Spoiler alert: it doesn't.
I did this one time. Ran over a pothole and bottomed out. As I'm replacing my front tire I look to my rear tire and see that it's also flat. That wasn't even the cherry on top. At that point I had my front wheel off and tried putting on the spare anyways.
I had a Kia Stinger GT and the GT version has Brembo brakes which have a much larger caliper than the regular version. Well QA at Kia never thought to check if their spare tire actually fits with the larger caliper. Spoiler alert: it doesn't.
Been there, with a GM with a similar issue.
The manual stated something about putting the spare on a rear, then, taking the good rear and putting it in the front.
The rotors on the rear were smaller and could accommodate the spare. Obviously a moot point if one has two blown tires.
The manual stated something about putting the spare on a rear, then, taking the good rear and putting it in the front.
The rotors on the rear were smaller and could accommodate the spare. Obviously a moot point if one has two blown tires.
If you can't fix the bug, document the work-around.
Same situation. I usually pride myself on having good situational awareness, but something about the shock of suddenly having a flat on a major highway took it out of me. I replaced my front right tire, pulled back into the slow lane, only to finally realize my back right tire had also been blown out. I called roadside assistance, left the car there, and Uber'd home.
That was a rough day.
That was a rough day.
How do you like the Stinger? I saw one of those the other day and did a double take on the Kia logo.
Are those spokes or springs? My mind had defaulted to "springs" given the zipzag shape and the typical function of a pneumatic tire. It didn't occur to me that they could function like spokes, where the vehicle hangs off the upper springs, until I read your comment. Why would the rim be so large and solid?
> Why would the rim be so large and solid
Not sure. Makes me think that it would be a good idea to make the inner rim diameter smaller, and have another layer of spokes/spings with a higher compression force.
Not sure. Makes me think that it would be a good idea to make the inner rim diameter smaller, and have another layer of spokes/spings with a higher compression force.
i'm pretty sure you'd have about a hundred whistles if you left the voids exposed at highway speed.
These tires do have sidewalls. The sidewalls are removed for marketing and demonstration purposes only.
I'm sure everyone in the tire industry (?) knows that, but it would be nice if Michelin had something to suggest that on their page.
The only little clue is that one photo of the EV where the sidewalls are visible on the tires. You have to squint to see it :)
Totally missed that on first reading, thank you for pointing it out.
good catch!
I guess the point is if they can be removed for demonstrations, then they're not critical to the structure.
They may be for real world usage, you dont want rocks or sticks getting inside
Absolutely, my point was that if you can remove them for this sort of demo, then if they get damaged by a pothole then it's probably easy to replace them.
The demo tires shown here don't have "removable" sidewalls. They were manufactured without them. The production tires will be one piece, like normal tires.
Sidewalls are critical for NVH at higher speeds, as well as fuel economy. But a demo of a tire on a car going 55 mph doesn't make sense, so they are able to remove the sidewalls for these stationary photoshoots and low speed rolling tests.
I imagine they're critical for noise reduction.
Additionally, tires filled with air can be dangerous over or under filling them.
Filling tires at too high pressure can lead to blowouts.
Filling tires under pressure leads to degraded performance handling issues potentially causing accidents in some cases.
A more consistent normalized baseline performing tire, even if louder, would be welcome. This would end the seasonal low pressure tires in winter due to the cold and higher pressure during summer due to the heat.
One time we got new tires and went on vacation and parked our car in an outside parking garage in a hot summer for a week, we came back and the side facing the sun the tires had exceeded PSI max and started to buckle. I am sure we have all seen those videos of people standing over tires and overfilling them leading to essentially a pressure bomb. Managing air pressure in tires can be problematic, airless tires are a welcome innovation.
Filling tires at too high pressure can lead to blowouts.
Filling tires under pressure leads to degraded performance handling issues potentially causing accidents in some cases.
A more consistent normalized baseline performing tire, even if louder, would be welcome. This would end the seasonal low pressure tires in winter due to the cold and higher pressure during summer due to the heat.
One time we got new tires and went on vacation and parked our car in an outside parking garage in a hot summer for a week, we came back and the side facing the sun the tires had exceeded PSI max and started to buckle. I am sure we have all seen those videos of people standing over tires and overfilling them leading to essentially a pressure bomb. Managing air pressure in tires can be problematic, airless tires are a welcome innovation.
> A more consistent normalized baseline performing tire, even if louder, would be welcome.
Background noise can lead to fatigue, which can lead to crashes. I have no idea of the overall impact (pardon the pun) of this, compared to increased safety of (louder) tyre performance, but probably worth considering.
> Managing air pressure in tires can be problematic, airless tires are a welcome innovation.
True, but modern cars have inbuilt pressure sensors, and these can be retro-fitted relatively cheaply.
Background noise can lead to fatigue, which can lead to crashes. I have no idea of the overall impact (pardon the pun) of this, compared to increased safety of (louder) tyre performance, but probably worth considering.
> Managing air pressure in tires can be problematic, airless tires are a welcome innovation.
True, but modern cars have inbuilt pressure sensors, and these can be retro-fitted relatively cheaply.
I'm in the same boat.
I lose 1-2 tires per year due to sidewall damage from potholes. Lucky for me, the Discount Tire road hazard warranty covers that. Costs me $16/tire each time this happens.
It's so bad that I had to replace the factory wheels with aftermarket ones that wouldn't get bent from the impact.
Of course, I didn't consider changing the wheel size when I did that. I should have gone with 15" wheels and a higher ratio tire to get the same effective outside radius with more tire between the wheel and the road.
Oh well, replacing this car soon anyways as now I am in need of ground clearance and AWD due to having moved to where roads do not always exist year round.
I lose 1-2 tires per year due to sidewall damage from potholes. Lucky for me, the Discount Tire road hazard warranty covers that. Costs me $16/tire each time this happens.
It's so bad that I had to replace the factory wheels with aftermarket ones that wouldn't get bent from the impact.
Of course, I didn't consider changing the wheel size when I did that. I should have gone with 15" wheels and a higher ratio tire to get the same effective outside radius with more tire between the wheel and the road.
Oh well, replacing this car soon anyways as now I am in need of ground clearance and AWD due to having moved to where roads do not always exist year round.
Same here. In over forty years of driving I have had only two tyres fail that I noticed while driving: one went flat over a period of a few seconds and the other was as you described, a pothole, I was only doing about 30 km per hour but the tyre was damaged beyond repair. In addition I've had a couple of slow leaks due to nails embedded in the tread but they were so slow that I didn't notice for days.
Punctures are much more of a problem for me - the roads are generally good, but tradies seem to love scattering nails, bolts, and other random bits of construction crap on the roads.
Fun fact, almost half of particulate road pollution comes from conventional tyres.
Not clear whether these new airless tyres will help or worsen that. More resistance = more wear, I would assume. Anyone?
https://www.imperial.ac.uk/news/195595/worlds-first-device-c...
Not clear whether these new airless tyres will help or worsen that. More resistance = more wear, I would assume. Anyone?
https://www.imperial.ac.uk/news/195595/worlds-first-device-c...
I head looked at these before, and only now noticed they that talk about retreading/ recharging treads by 3D printing- this doesn’t directly address the particulate issue but is a very interesting idea for reducing the waste from worn tyres more generally.
I don't think it will change much. Friction between the wheel and the road will continue, and the surface of the new tire will still need to wear and be replaced.
16 years ago, I was an intern at the European HQ of a Japanese tyre brand.
We received and chain forwarded a "leaked" video of Michelin testing a similar design.
We ICT folks thought we were doomed as it seemed miles ahead of our own R&D.
16 years later and we are yet to see these tyres on the streets.
This time, I'll believe it when I see it ;)
We received and chain forwarded a "leaked" video of Michelin testing a similar design.
We ICT folks thought we were doomed as it seemed miles ahead of our own R&D.
16 years later and we are yet to see these tyres on the streets.
This time, I'll believe it when I see it ;)
The page uses the phrase "revolutionary structure". It's a fascinating pun to make about a wheel. I wonder if it's intentional.
Or it could just be both...a wheel with revolutionary structure, since wheels are nowadays so much more of an engineering project than a simple circle drawing in a book on theory...
Wouldn't these be great for trailers? Trailer blowouts are common, and often unnoticed, or can heavily damage the trailer. I have no interest in these on a car, but for a trailer, sign me up!
I think they'd be better for trailers than cars because all the tradeoffs people are complaining about (small increase in rolling resistance, NVH, inability to air up for increased load or down for comfort) are far lesser in a trailer application. Combine that with all the trailer tires that go bad from long term exposure to the elements before they get worn out and it seems like an obvious application.
But..... one of the most important aspects about trailer tires is cost and these may not quite be there yet. Michilin and other tire manufacturers don't really compete much in that space and leave it for the low end import brands to fight over.
Rental trailers and towed equipment (like towed light plants and air compressors) seems like the only obvious niche where both the cost and downsides are justifiable.
But..... one of the most important aspects about trailer tires is cost and these may not quite be there yet. Michilin and other tire manufacturers don't really compete much in that space and leave it for the low end import brands to fight over.
Rental trailers and towed equipment (like towed light plants and air compressors) seems like the only obvious niche where both the cost and downsides are justifiable.
Seems like it's 404ing now; here's a snapshot: https://archive.is/9m1gs
Interesting that they say nothing about consumption. I would expect them to be less fuel efficient, but having some number to go by would be nice.
As a general rule, tweels are worse for fuel consumption -- they are both heavier and have more rolling resistance. (Edit: weight automatically adds rolling resistance, but so does flexion, which tweels have more of. So tweels are a double-whammy for fuel economy.)
I wonder how that breakdown works for under inflated and overinflated tires, and what percentage of the nations tires are in that state at any moment?
For a consumer product like this I think it's probably more important to compare the common case than the optimal case, because I know my tires often aren't in an optimal state, and as much as we could save as a nation by making sure tires were inflated correctly, we just don't, and I don't expect that to change meaningfully.
For a consumer product like this I think it's probably more important to compare the common case than the optimal case, because I know my tires often aren't in an optimal state, and as much as we could save as a nation by making sure tires were inflated correctly, we just don't, and I don't expect that to change meaningfully.
Overinflated tires will always have better economy than underinflated, all other things being equal. My guess is the average vehicle owner could improve overall fuel economy by about 0.5-1.0% by making sure their tires are at the correct pressure.
So, my thought when I said that was back when Obama mentioned keeping tires inflated correctly and getting tuneups to reduce oil consumption, and looking into that lead to this[1], which puts it at 0.6% on average, but up to 3% in specific cases.
So I guess the question is how does 0.6% fuel economy loss on average for current tires compare to the loss in efficiency for using a Tweel, but according to some data from Michelin here[2], it looks like they're actually projecting them to be more efficient than current tires? I didn't read through the whole analysis, so I'm not sure, but that's what Table 7 looks like to me at a cursory glance and reading a few paragraphs in that section.
1: https://www.fueleconomy.gov/feg/maintain.jsp
2: https://manufacturing.gatech.edu/sites/default/files/uploads...
So I guess the question is how does 0.6% fuel economy loss on average for current tires compare to the loss in efficiency for using a Tweel, but according to some data from Michelin here[2], it looks like they're actually projecting them to be more efficient than current tires? I didn't read through the whole analysis, so I'm not sure, but that's what Table 7 looks like to me at a cursory glance and reading a few paragraphs in that section.
1: https://www.fueleconomy.gov/feg/maintain.jsp
2: https://manufacturing.gatech.edu/sites/default/files/uploads...
Funny -- I presented a paper at that very same conference! Mine was 2011-01-0755.
The money shot is here. Note that '5.5 kg/ton' refers to the rolling resistance of the tire.
> At this point the 5.5 kg/ton value is still only a design target, and this study serves mainly to confirm the environmental value of achieving that target.
Essentially, this conclusion is tautological. "If there were a tweel that had better rolling resistance than the best pneumatic tire on the market, then it will have a better fuel economy and environmental impact." Obviously!
I seriously doubt Michelin's tweel is anywhere close to that 5.5 kg/T mark. It's more likely something like 12 kg/T.
The purpose of this particular paper is not to show that tweels are better environmentally, it is to show an analytical framework for calculating the full-lifecycle environmental impact of tweels vs tires. Sort of like a "here are the equations, plug in real numbers later" kind of thing.
The money shot is here. Note that '5.5 kg/ton' refers to the rolling resistance of the tire.
> At this point the 5.5 kg/ton value is still only a design target, and this study serves mainly to confirm the environmental value of achieving that target.
Essentially, this conclusion is tautological. "If there were a tweel that had better rolling resistance than the best pneumatic tire on the market, then it will have a better fuel economy and environmental impact." Obviously!
I seriously doubt Michelin's tweel is anywhere close to that 5.5 kg/T mark. It's more likely something like 12 kg/T.
The purpose of this particular paper is not to show that tweels are better environmentally, it is to show an analytical framework for calculating the full-lifecycle environmental impact of tweels vs tires. Sort of like a "here are the equations, plug in real numbers later" kind of thing.
Ah, nice to know, and thanks for giving a professional's assessment of what's being said. :)
:) Not a problem! Your experience hangs a lantern on one of the problems in academia.
The authors of that paper did not intend to mislead -- this paper was published in 2011, likely written in 2010, only a handful of years after Michelin's unveiling of their gen 1 tweel design. To me, having been in the authors' position, I can easily tell what the true purpose of the paper actually was (the analytical procedure). But the authors had a secondary purpose driven by 'hype', almost, you could even call it click-bait: they wanted to make the tweel exciting so that other researchers would get interested in it and continue the work. One way to do that is by showing, from a materials perspective, that it is theoretically possible to design a tweel with a low rolling resistance, and given that, it's possible that tweels will be better for the environment over the full-lifecycle, including manufacturing and materials. And sure, this absolutely did/does deserve more research. However, the other issues with tweels, like NVH/comfort/etc, were 'out-of-scope' for that paper, and so they ignored those. Solving for those issues is what makes that 5.5 kg/T figure difficult/possibly impossible to attain.
When these papers are confined to academia, it all works out, because most of the people who read your paper are other people who are writing papers, and they get it. But once these types of papers are picked up by the press/media/general populous, they can be very quickly misinterpreted!
(To be clear, you didn't do anything wrong here, I'm just griping a bit about academia and pretending like I'm 'adding context' ;)
The authors of that paper did not intend to mislead -- this paper was published in 2011, likely written in 2010, only a handful of years after Michelin's unveiling of their gen 1 tweel design. To me, having been in the authors' position, I can easily tell what the true purpose of the paper actually was (the analytical procedure). But the authors had a secondary purpose driven by 'hype', almost, you could even call it click-bait: they wanted to make the tweel exciting so that other researchers would get interested in it and continue the work. One way to do that is by showing, from a materials perspective, that it is theoretically possible to design a tweel with a low rolling resistance, and given that, it's possible that tweels will be better for the environment over the full-lifecycle, including manufacturing and materials. And sure, this absolutely did/does deserve more research. However, the other issues with tweels, like NVH/comfort/etc, were 'out-of-scope' for that paper, and so they ignored those. Solving for those issues is what makes that 5.5 kg/T figure difficult/possibly impossible to attain.
When these papers are confined to academia, it all works out, because most of the people who read your paper are other people who are writing papers, and they get it. But once these types of papers are picked up by the press/media/general populous, they can be very quickly misinterpreted!
(To be clear, you didn't do anything wrong here, I'm just griping a bit about academia and pretending like I'm 'adding context' ;)
Yeah, I'm totally aware of how hard it is to accurately assess and relate info from a technical paper without experience in the industry, which is why I try to make sure I express how little confidence I have in how I'm relating that info, given I very rarely have time to actually dive deep into a paper when looking something up like this.
In some ways what you describe is a very common larger problem. When you want to promote something (whether it be because of financial or more altruistic reasons), its hard (possibly impossible) to walk the fine line for all people between accurately relaying information and convincing people of something less factual (such as "this is cool and we should look into it more"), namely because different audiences' relative experience in the area will mean they won't recognize where that line is in many cases.
For example, at exactly what point does a website or description for some open source project move from purely descriptive explanations of what it can do to promotion about why it's cool and why you should try it? People with different experience in the domain it's in will have difference experiences ready that info. The neophyte and the layman will interpret the statements differently.
In some ways what you describe is a very common larger problem. When you want to promote something (whether it be because of financial or more altruistic reasons), its hard (possibly impossible) to walk the fine line for all people between accurately relaying information and convincing people of something less factual (such as "this is cool and we should look into it more"), namely because different audiences' relative experience in the area will mean they won't recognize where that line is in many cases.
For example, at exactly what point does a website or description for some open source project move from purely descriptive explanations of what it can do to promotion about why it's cool and why you should try it? People with different experience in the domain it's in will have difference experiences ready that info. The neophyte and the layman will interpret the statements differently.
TPMS has been law in the US since 2007. People might be driving around with under inflated tires, but there is a light on if they are.
TPMS doesn't alert until tires are something like 25-30% under pressure, which is pretty severe.[1]
[1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalr... (page 10)
[1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalr... (page 10)
My cold tire pressure is supposed to be 33PSI, my TPMS doesn't alert until it's below 28PSI, so there is a significant delta still.
The TREAD law does not specify when TPMS must alert, other than the tire being 'significantly underinflated'.
The TREAD law does not specify when TPMS must alert, other than the tire being 'significantly underinflated'.
The NHTSA has determined that the requirement is that TPMS alerts for 25% underinflation across any combination of tires, or 30% underinflation in a single tire.[1] Originally they wanted 20-25%, but determined that cheap TPMS sensors were not good enough to meet that threshold and did not want to impose the cost of better sensors.
[1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalr...
[1]: https://www.nhtsa.gov/sites/nhtsa.gov/files/fmvss/TPMSfinalr...
The magic of the pneumatic (air-filled) tire is that the entire air-filled space of the tire acts to absorb shock and vibration from the road surface.
Airless tires give up this advantage, and only the tire structure between the wheel and contact patch are available to do the same work.
The result is always a heavier tire that is a harsher ride. All the materials science in the world can't and won't find a solution to this. You can safely ignore any airless system for all but the most specialized applications.
Airless tires give up this advantage, and only the tire structure between the wheel and contact patch are available to do the same work.
The result is always a heavier tire that is a harsher ride. All the materials science in the world can't and won't find a solution to this. You can safely ignore any airless system for all but the most specialized applications.
The result is also always an efficiency loss. Periodically solid bike tires become faddish and it's like pedaling a bike made of lead.
Previous related thread here (about one month ago):
https://news.ycombinator.com/item?id=28537549
https://news.ycombinator.com/item?id=28537549
Thanks. Second comment:
"""
I am an engineer working in the tire industry (throwaway is needed here). The Michelin "Tweel" IP was actually acquired when Michelin bought BF Goodrich 31 years ago. Goodrich developed the concept as a replacement for compact spare tires, doing the initial R&D in the 1980s. Every 3--5 years Michelin has a press release like this, and the technology is always 3--5 years away from release. Currently the US DOT and it's equivalents abroad are still in the rulemaking phase regarding airfree technologies, so there's that, too.
"""
"""
I am an engineer working in the tire industry (throwaway is needed here). The Michelin "Tweel" IP was actually acquired when Michelin bought BF Goodrich 31 years ago. Goodrich developed the concept as a replacement for compact spare tires, doing the initial R&D in the 1980s. Every 3--5 years Michelin has a press release like this, and the technology is always 3--5 years away from release. Currently the US DOT and it's equivalents abroad are still in the rulemaking phase regarding airfree technologies, so there's that, too.
"""
Which brings up the one ideal use for these that hasn't been mentioned: spare tires, if you can make them narrower with the same load capacity.
I am skeptical that these will be better for the environment. Maybe there will be fewer tires discarded due to flats, but the tires will weigh more. That's more material discarded per tire and more energy to drive them around.
Maybe I am wrong, but I think I've red somewhere that these are made to be re-threaded. Meaning when the outer layer get damaged with use, instead of changing the whole tire, just the outer part can be replaced. Not too sure how that works though. If that is the case, it should help reduce the amount of waste by a lot. Plus even if these new tires are heavier, I doubt they are 10 times heavier either. I'd be surprised if the added weight to the car will increase the energy consumption in a very noticeable way.
They call it ‘recharging’ on this page. They even propose converting between summer/winter by reprinting the tread.
Pneumatic tires can also be retreaded. But we generally don't do it for passenger cars. I'm not sure of the reasons why so I can't say whether these tires address any of them. I'd want to see some explanation before I believe it.
Surely the ability to recycle/repurpose an old tyre matters more than the flats, so I'm not sure how this helps.
Also, I see the biggest concern as degradation of tyres contributing to rubber-dust pollution: "according to the UK government, and they are the second largest source of microplastic pollutant in oceans after single-use plastic"
Seems like it would be better to find an eco-friendly alternative to tyre rubber instead. If this design allows that (e.g. by allowing tyre materials that aren't as stretchy as an inflatable would need to be) I'm all for it, but that's a more complicated definition of "good for environment", dependant on other tech being developed.
Also, I see the biggest concern as degradation of tyres contributing to rubber-dust pollution: "according to the UK government, and they are the second largest source of microplastic pollutant in oceans after single-use plastic"
Seems like it would be better to find an eco-friendly alternative to tyre rubber instead. If this design allows that (e.g. by allowing tyre materials that aren't as stretchy as an inflatable would need to be) I'm all for it, but that's a more complicated definition of "good for environment", dependant on other tech being developed.
I remember reading about airless tires back when I was in high school and it seemed like the concept was ready for mass production in a couple years. That was around 2004~5 ish. I wonder how much has changed and how close are others, like bridgestone.
What I like about companies like Apple is when they release something, they explicitly say: "This product will be available in stores starting Oct 15". On Oct 15, you go to apple.com and buy the product online. Done. I can't even count how many years I've heard about airless tires being developed.
You don't like to open R&D status but like secret?
Michelin has been talking about these things for years and has yet to actually put them into production. All talk and no show.
I get that "no punctures means less waste", and
"Every year, 20%* of tires are discarded as scrap due to flats and rapid pressure loss (12%) or irregular wear and tear caused by poor tire pressure (8%), i.e., the equivalent of 200 million tires, or 2 million tonnes*. That’s 200 times the weight of the Eiffel Tower."
However, there is still the problem of getting rid of "a flexible load-bearing structure made from glass fiber reinforced plastic (GFRP)".
I would hope there is a way to degrade, reclaim or reuse these materials.
However, there is still the problem of getting rid of "a flexible load-bearing structure made from glass fiber reinforced plastic (GFRP)".
I would hope there is a way to degrade, reclaim or reuse these materials.
> I would hope there is a way to degrade, reclaim or reuse these materials.
Plasma gasification
Plasma gasification
I will believe it once I see them drive the same tires on West Michigan roads for 29k miles during the spring. We’ve had highways just disintegrate during the thaw here.
> Airless technology will drastically reduce the number of tires that are scrapped because of punctures.
Well, maybe, but don't these new tires use more rubber instead of air? In which case they will actually increase the amount of discarded tires? Also, what about the recycling potential of these tires?
I'm not an automotive buff, but this claim of being "good for the environment" sounds like just empty marketing talk.
Well, maybe, but don't these new tires use more rubber instead of air? In which case they will actually increase the amount of discarded tires? Also, what about the recycling potential of these tires?
I'm not an automotive buff, but this claim of being "good for the environment" sounds like just empty marketing talk.
What does this mean for those 'severe tire damage' traffic control devices?
It means they probably won't work anymore. But they're mostly theater anyway; they are easily defeated.
I always wonder how these things would stand up to stones getting caught in between the rubber “spokes“.
I don't think that part of the tire is open to the outside -- you're seeing a cross-section in the pictures and video.
For airless tires I've used a 4x4 (quad), the tires are open on the side just like these images.
For a passenger vehicle application, these tweels will have sidewalls. You don't hit highway speeds on your quad and that makes all the difference.
In fact you can see that the photo of the EV on their site has sidewalls.
In fact you can see that the photo of the EV on their site has sidewalls.
[deleted]
These tires have sidewalls, the spokes are not exposed. Without sidewalls these tires would be very loud on the highway, and would have a much higher rolling resistance.
I thought that at first too but then wondered if the views are simply a cross section, where the final tire will have that part covered as a regular tire would with rubber.
Completely guessing, but I wonder if they designed the "spoke" baffles to pinch in under the load and thus expel any stones that might fit between them, like a pebble squeezed between your two fingers and shooting out.
A pebble shooting out of the upper side of a tire of a car at 250 km/h is probably as bad as a bullet. Probably worse.
So about the same as a pebble that gets stuck in treads or kicked up by same? Definitely better than a bullet though just by nature of lower speed, what it's made of and because of its poor aerodynamics.
These spokes seem to be able to fit larger pebbles that may be launched from the side of the wheel and escape the wheel well.
I wonder, how would airless tires be able to handle offroading? On the one hand they seem like the perfect candidate as running over a rock or stick won't cause the tire to puncture. But on the other hand you loose the ability to air down the tire for more traction.
Weren’t we trying to reduce plastic waste? This seems to need multiple times the amount of rubber that a normal tire needs. And for what? To prevent a fixable puncture that may or may not happen in a lifespan of a tire?
Have you ever been driving when a tire blew out at high speed? It's extremely dangerous not only for the driver but all the nearby cars.
This is a tradeoff between environmental concerns and safety, as are most safety features on a car. We could make a car that gets insanely good milage and has little raw material, but it would be terribly unsafe.
This is a tradeoff between environmental concerns and safety, as are most safety features on a car. We could make a car that gets insanely good milage and has little raw material, but it would be terribly unsafe.
You are not talking about a puncture. You are talking about a catastrophic collapse of the tire from an impact (damn potholes) that has happened to me.
I don’t see how these tires are immune to catastrophic failure that typically can take with it the rim and the suspension.
I don’t see how these tires are immune to catastrophic failure that typically can take with it the rim and the suspension.
Punctures can cause those catastrophic failures, especially when they hit the edge near the sidewall.
> Have you ever been driving when a tire blew out at high speed? It's extremely dangerous not only for the driver but all the nearby cars.
Have you? Your characterization of the experience makes me think you have not.
I have had two rear and one front blowout. Blowouts are just flat tires that have a loud intro before the typical "driving on flat tire" music. None of them were any more eventful than a normal flat tire. I'd take a blowout (or normal flat tire) over tread separation any day.
The internet highly highly highly highly highly overrates the danger, likely because blowouts are so rare these days and unfamiliarity tends to result in fear which compounds the Internet's tendency to reward certain commenting patterns. Other than the noise potentially causing a driver to incorrectly make massive control inputs (which would be equally hazardous to do after suffering a normal flat) there is no more hazard from a blowout than from a normal flat. And I say this as someone who drives old junk with fat sidewalls. On something with small modern sidewalls all the danger is less still.
Frankly, the one time I had a valve stem leak that caused a slow flat was much more unnerving as I initially wasn't sure if I was feeling things or if the vehicle was pulling to that side.
Have you? Your characterization of the experience makes me think you have not.
I have had two rear and one front blowout. Blowouts are just flat tires that have a loud intro before the typical "driving on flat tire" music. None of them were any more eventful than a normal flat tire. I'd take a blowout (or normal flat tire) over tread separation any day.
The internet highly highly highly highly highly overrates the danger, likely because blowouts are so rare these days and unfamiliarity tends to result in fear which compounds the Internet's tendency to reward certain commenting patterns. Other than the noise potentially causing a driver to incorrectly make massive control inputs (which would be equally hazardous to do after suffering a normal flat) there is no more hazard from a blowout than from a normal flat. And I say this as someone who drives old junk with fat sidewalls. On something with small modern sidewalls all the danger is less still.
Frankly, the one time I had a valve stem leak that caused a slow flat was much more unnerving as I initially wasn't sure if I was feeling things or if the vehicle was pulling to that side.
I have. Front tire blew out, caused the car to swerve uncontrollably to the right. Luckily no one was there an I knew not to slam on the brakes but to downshift instead.
But yes, in many cases it just drags the car. None the less, it can cause huge issues.
But yes, in many cases it just drags the car. None the less, it can cause huge issues.
My reaction too. I would say the number of scraped tires due to wear far exceed those scrapped due to puncture. Also it looks like this airless tire contains much more rubber, that would increase the tire weight and would impact the fuel consumption. The final weight of rubber scrapped may also increase compared to conventional tiers. Airless tires have been discussed for many years, this is only marketing and brand PR.
Do tire manufacturers really have the desire to develop tires with less tear?
I'm unimpressed with their pilot location choice. Las Vegas?
Chicago or NYC would be much more of a proper test with potholes, humidity, potholes, temperature, potholes, and precipitation. Did I mention potholes.
Chicago or NYC would be much more of a proper test with potholes, humidity, potholes, temperature, potholes, and precipitation. Did I mention potholes.
I wonder what the speed rating of these will be.
(I'd guess they would overheat really fast if you drove them even moderately fast, plus the inertia would be pretty insane?)
(I'd guess they would overheat really fast if you drove them even moderately fast, plus the inertia would be pretty insane?)
I had the same thought, but they probably have cooling built in to the hub.
Good video I just found
https://m.youtube.com/watch?v=Ql0Mkr3dwNU
shouldnt they be “closed” laterally for aerodynamics, to block dirt and snow from getting stuck inside? guess these will collect dirt 100 times more than regular tires no?
update: similar questions here https://m.youtube.com/watch?time_continue=206&v=sc8ghIqKqnI&...
update: similar questions here https://m.youtube.com/watch?time_continue=206&v=sc8ghIqKqnI&...
In another comment it was mentioned that there will doubtlessly be "sidewalls" on actual airless tires, and that the exposed ones shown on this page are just for show. I admit that makes a lot of sense given your point about dirt/rocks entering in and effecting the absorption effect of the honeycomb.
They will have walls, this is just a demo model to show the internals.
I have airless tires in the same bucket as flying-cars and video-phones (things that sort of exist, but are always just around the corner from being widely adopted).
(I realize that video-phones are kind of widely adopted now via Zoom/Facetime/etc. - I'm thinking more of the vision from the 90s of a telephone with a screen in your kitchen)
(I realize that video-phones are kind of widely adopted now via Zoom/Facetime/etc. - I'm thinking more of the vision from the 90s of a telephone with a screen in your kitchen)
Those are also widely available now (ie Facebook Portal + similar), but nobody needs them. My grandparents had a similar model which they used until a few years ago.
Cool stuff. I hope they make it onto the road. What was really interesting to me is that the page suggests that most of their on road testing is done in the US. Michelin is a French company and there are lots of good European card companies. Does anyone know why they wouldn't do their testing in Europe?
Also handy for Michelin revenues that the wheel is integrated.
Yes, I get that it might be hard for them to be separate.
Yes, I get that it might be hard for them to be separate.
It's dirty out here in the real world. What happens when those grooves get plugged up with mud, bits of glass & other tires and dead squirrels?
But I'll admit, I do want the "Picyures to download".
Is it only hype? What about road adherence, endurance, etc. As long as I don't see independent assessments by car journalists, I'll reserve my judgement.
But if they live up to the hype, it will be a game changer indeed.
But if they live up to the hype, it will be a game changer indeed.
IIRC they have some interesting attributes. Lateral stiffness is incredibly high, but IIRC rolling resistance is higher and they are quite a bit heavier than standard tires. Seems like there might be some interesting capabilities to pump air one way or the other for aero purposes.
From my understanding, the dealbreaker is that these tires are incredibly noisy at highway speeds.
I hope the open sides will be closed up because those are going to be grime collectors if exposed to the weather. I'd expect them to be full of crap before the first month of use is out.
Edit: apparently they are.
Edit: apparently they are.
I wonder if the rubber structural spokes could be shaped to pull air from the underside of the vehicle (tire rotation would be slightly more complicated) to increase stability at higher speeds.
Or cooling.
There also might not be expansion with increase temperature?
The wheels themselves could pull air through the brake disks, but their rotation and the shape of ventilated disks already help with that.
I think I'll need to instrument my car. If something like this works, it'll seem from the inside the gets heavier the faster it goes in addition to what clever airfoils and aerodynamic design already does.
I think I'll need to instrument my car. If something like this works, it'll seem from the inside the gets heavier the faster it goes in addition to what clever airfoils and aerodynamic design already does.
This design looks to be much less mosquito-breeding-friendly than traditional tires at least. I was shocked when I learned how much "help" discarded tires lend to mosquito breeding.
Fiberglass doesn't recycle well, does it?
https://www.youtube.com/watch?v=Ql0Mkr3dwNU
https://www.youtube.com/watch?v=Ql0Mkr3dwNU
Nice, I have seen this tech ~25 years ago when I was a little boy and always wondered why it never came to market. I think they were called tweels back when I saw them.
I see a LOT of lawnmowers in my area with this kind of tire. It's especially prevalent on the larger, commercial mowers that landscape professionals use.
These being around forever, but not being released, I wonder how much of why this is happening now is because they're finally coming off patent?
Could these be used to drive over the spokes at a checkpoint or garage that prevent entry?
Would that have any impact, f such tires would become popular?
Would that have any impact, f such tires would become popular?
The 3rd illustration displayed (the one that accompanies the claim “A smaller environmental footprint”) is extremely enigmatic…
I'm a bit confused. Are they going to leave the sides open like that? What if a pebble gets stuck in there?
Interesting - the design seems to have built-in v-shaped rubber shock absorbers all around the tire.
"Every year, 20%* of tires are discarded as scrap "
Really? They cite a survey, but don't link to it.
Really? They cite a survey, but don't link to it.
Tires are usually rated for 40 ,000 to 60,000 miles. Americans drive 13,500 miles per on average[1]. That would cause tires to be replaced on average after ~4 years. So yeah, seems believable.
[1] https://www.fhwa.dot.gov/ohim/onh00/bar8.htm
[1] https://www.fhwa.dot.gov/ohim/onh00/bar8.htm
I have never gotten the rated tread lifetime on a tire. I've gone through maybe 60 tires in my lifetime and none of them were replaced due to punctures (I had one repairable puncture). Partly because 90% of my miles are stop/go rather than cruising.
The number doesn't seem to far off. I have summer and winter tires, replace them every 6-7 years. Lots of people drive more than I do.
You misunderstood; the claim is that 20% of the tires that are discarded are due to punctures or improper inflation.
12% of the tires that are discarded are discarded due to punctures or blowouts and 8% of tires that are discarded are discarded due to uneven wear caused by improper inflation.
12% of the tires that are discarded are discarded due to punctures or blowouts and 8% of tires that are discarded are discarded due to uneven wear caused by improper inflation.
I don't drive that much and still feel that changing tyres every five years is pushing it.
[deleted]
Ride comfort on those?
Ride comfort on tweels has historically been poor. But Michelin seems to be claiming they've solved that problem for this generation.
The same claim has been made yearly for the past century and a half.
I don't think that any advancement in materials or mechanical science can create a solution that outperforms the advantages of a standard pneumatic tire.
I don't think that any advancement in materials or mechanical science can create a solution that outperforms the advantages of a standard pneumatic tire.
Tyre waste arguments seem like absolute nonsense.
I wonder how hot those spokes get at speed.
Would these work on Mars rovers too?
Mars rovers already use tires like these.
Or how about bicycles?
Spring tyres were used on bicycles in World War One
https://onlinebicyclemuseum.co.uk/ww1-german-bicycles/
https://onlinebicyclemuseum.co.uk/ww1-german-bicycles/
Superwheels, discussed here (but tyres remain conventional):
https://news.ycombinator.com/item?id=25158215
https://news.ycombinator.com/item?id=25158215
Tweels are probably too heavy to be viable on bicycles.
> The companies will advance feasibility studies seeking to make this new tire available in market by 2019.
Given that I haven't seen tweels for bicycles yet, I assume the feasibility studies did not go well.
It also looks like they also announced that bicycle tweels were 'coming soon' nearly two years ago: https://jalopnik.com/bridgestone-says-airless-tires-are-comi...
Given that I haven't seen tweels for bicycles yet, I assume the feasibility studies did not go well.
It also looks like they also announced that bicycle tweels were 'coming soon' nearly two years ago: https://jalopnik.com/bridgestone-says-airless-tires-are-comi...
They aren't airless, they just don't depend on compressed gas.
By that definition, almost nothing but the vacuum of space is airless. Even a galvanized rubber hockey puck is going to have some amount of air in it.
Airless in this case means that they don't use pressurized air for rigidity, and therefore they do not need to be engineered to maintain air pressure, thereby reducing material input, and removing a major failure mode.
They are wheel-shaped springs.
Airless in this case means that they don't use pressurized air for rigidity, and therefore they do not need to be engineered to maintain air pressure, thereby reducing material input, and removing a major failure mode.
They are wheel-shaped springs.
the michelin man is so full of air though
Getting 404 now
They seem to be marketing these alongside EVs, I wonder if they're only really intended for lighter, compact-style cars. (Edit: I'm talking about EVs like the BMW i3, which are on average about 1000 lbs lighter than the cars most Americans drive, ie, the CUV/SUV form factor.)