Aerodynamic drag in small cyclist formations: shielding the protected rider [pdf](urbanphysics.net)
urbanphysics.net
Aerodynamic drag in small cyclist formations: shielding the protected rider [pdf]
http://www.urbanphysics.net/2025_Formation_Paper_Preprint_v1.pdf
18 comments
>having a single rider at the front saves the energy of the teammates
Also (as mentioned briefly in the paper), longer pace lines result in reduced drag for the rider at the front. This can seem counter-intuitive, but it's basic streamlining - the following riders fill in the low-pressure region behind the lead rider, reducing the amount of flow separation. Riding two-abreast is actually slower than riding individually.
A really efficient pace line looks like a team pursuit, with the rider on the front doing very short stints before peeling off and joining the back of the line. This is hugely important for physiological reasons, because it allows the lead rider to briefly exceed their aerobic threshold and then recover.
https://www.sciencedirect.com/science/article/pii/S016761051...
https://www.youtube.com/watch?v=pSq_JvD9w0g
Also (as mentioned briefly in the paper), longer pace lines result in reduced drag for the rider at the front. This can seem counter-intuitive, but it's basic streamlining - the following riders fill in the low-pressure region behind the lead rider, reducing the amount of flow separation. Riding two-abreast is actually slower than riding individually.
A really efficient pace line looks like a team pursuit, with the rider on the front doing very short stints before peeling off and joining the back of the line. This is hugely important for physiological reasons, because it allows the lead rider to briefly exceed their aerobic threshold and then recover.
https://www.sciencedirect.com/science/article/pii/S016761051...
https://www.youtube.com/watch?v=pSq_JvD9w0g
Yeah, this is how you do it. Everybody pulls but the protected one. I've been in team time trial situations where we had to protect one (it me, but we won), even two, and goddam that pull through could be hard but I made it.
CFD simulation indicating leader is assisted by followers: http://dx.doi.org/10.1051/epn/2013102
Ah I see your cite shares the same lead author. Likely a better paper.
CFD simulation indicating leader is assisted by followers: http://dx.doi.org/10.1051/epn/2013102
Ah I see your cite shares the same lead author. Likely a better paper.
Really efficient pace lines are basically diamonds with the exchange of riders at front which usually only do 10 seconds of exposure in front tops.
I watched a lot of the Tour de France and if I had seen the paper before that I would have looked out for any of these formations with two riders in front. Were there any instances where they used these formations? I only remember single leader formations (often lead by Tim Wellens for an impressively long time), but there might have been other formations that I just missed.
> Were there any instances where they used these formations?
Half of it, when in echelon form during crosswinds. Which is pretty much the only situation where any of this will work in practice since as mentioned elsewhere many times you don't burn all your people at once. Energy isn't endless.
Half of it, when in echelon form during crosswinds. Which is pretty much the only situation where any of this will work in practice since as mentioned elsewhere many times you don't burn all your people at once. Energy isn't endless.
To add to sibling comment, in the peleton you generally dont have the luxury of choosing your formation down to such fine detail. Theres lots of other riders fighting for space.
And breakaways are rarely a team affair. You get some towards the end of mountain stages, but uphill all of this maths goes away (everyone is much slower and air drag matters less).
And breakaways are rarely a team affair. You get some towards the end of mountain stages, but uphill all of this maths goes away (everyone is much slower and air drag matters less).
At least with the diamond formation you have the opportunity of rotation but the two in the middle will still tire quickly, and I don’t know how you safely rotate in that configuration. Any beginning serious cyclist can learn to draft. But the pros have got rotating the formation down to a science. You have to go fast without increasing the risk of high speed collision.
In the scenarios mentionned ( getting back to the front ), usually the single line is the easiest to do because of the riders having to navigate between the team cars, road furnitures, dropped riders, etc. It is only really when you are at the front where you can go wherever you want.
The paper’s abstract asserts that race leaders get support from multiple riders to get back to the peloton. That’s just wrong. They use the team car and usually a single domestique to recover to the back of the peloton. Should they use more domestiques? Maybe but the the occasions where it matters would be very rare.
>The paper’s abstract asserts that race leaders get support from multiple riders to get back to the peloton. That’s just wrong.
Wrong if the leader gets dropped early on in a quiet stage, but absolutely true if they get dropped during a more difficult racing situation. I can think of numerous instances where the entire team has gone back to get the boss - it's an act of desperation, but it does happen, particularly at times when there are multiple groups on the road and the team cars aren't where you'd want them to be. It really isn't uncommon for two or three riders to go back if the boss loses a lot of time in a crash or a mechanical.
Perhaps more to the point, this general situation (needing to deliver the boss to the front in the most efficient way possible) is something that sprinter-led teams will do towards the end of practically every flat stage, in the form of a lead-out. The aerodynamics and tactics are slightly different than when recovering a dropped leader, but it's the same basic approach of using a pace line.
https://www.youtube.com/watch?v=qbUOUZGf_Qg
Wrong if the leader gets dropped early on in a quiet stage, but absolutely true if they get dropped during a more difficult racing situation. I can think of numerous instances where the entire team has gone back to get the boss - it's an act of desperation, but it does happen, particularly at times when there are multiple groups on the road and the team cars aren't where you'd want them to be. It really isn't uncommon for two or three riders to go back if the boss loses a lot of time in a crash or a mechanical.
Perhaps more to the point, this general situation (needing to deliver the boss to the front in the most efficient way possible) is something that sprinter-led teams will do towards the end of practically every flat stage, in the form of a lead-out. The aerodynamics and tactics are slightly different than when recovering a dropped leader, but it's the same basic approach of using a pace line.
https://www.youtube.com/watch?v=qbUOUZGf_Qg
It really depends of the race situation, if the peloton is riding hard or not, if it is at the beginning of the stage or later, if there are splits in the peloton which lead to blocus of the team vehicles at the back of a slower group than where all the GC favorites are riding, etc.
There is no single answer.
There is no single answer.
As a cyclist and avid fan of pro cycling, I don’t see this being so useful for transportation from a dropped position back to the peloton or breakaway. As others have noted, team cars help, and often the distance to close can be handled by one teammate. I forget which stage, but this year when Vingegaard had a mechanical and needed to swap bikes, Visma didn’t have any domestique wait for him! The protected rider is usually the best rider.
I was thinking about how this might be useful on the attack. Visma had several super domestiques remaining at the end of the tour (Jorgensen, Kuss, Simon Yates) and UAE had lost its top lieutenant. Could they have made a 2x2 train for Vingegaard? Well, maybe, but Pogacar would’ve just hopped on board. So not sure we would see this either.
Amateur rides with no cars and a wider divergence in cyclist abilities, maybe this is more useful.
I was thinking about how this might be useful on the attack. Visma had several super domestiques remaining at the end of the tour (Jorgensen, Kuss, Simon Yates) and UAE had lost its top lieutenant. Could they have made a 2x2 train for Vingegaard? Well, maybe, but Pogacar would’ve just hopped on board. So not sure we would see this either.
Amateur rides with no cars and a wider divergence in cyclist abilities, maybe this is more useful.
I also agree that it is more useful to semi-pro or amateur riders than the actual pro ones, especially because the formations are quite small (3, 4, and 5 riders) and as you mentioned, usually team cars help out (which is much nicer aerodynamic support than a single rider anyway)
Although, could be useful for the breakaways. I mean, sometimes breakaway forms with handful of riders, still, Pogi could jump into them, but that did not seem to be their (UAE) strategy recently, it was more like: Hold onto the Yellow jersey (GC) as long as possible, and don't take any risks...
As far as I can tell, a similar tactic lead to the Wout van Aert's win at the last stage of Tour de France. From 20km on, the breakaway had ~5 people, Wout waited at he back (essentially a `-==` formation) until the last ~5km, and dropped Pogacar at the climb, then extended nearly a minute difference until the finish.
Although, could be useful for the breakaways. I mean, sometimes breakaway forms with handful of riders, still, Pogi could jump into them, but that did not seem to be their (UAE) strategy recently, it was more like: Hold onto the Yellow jersey (GC) as long as possible, and don't take any risks...
As far as I can tell, a similar tactic lead to the Wout van Aert's win at the last stage of Tour de France. From 20km on, the breakaway had ~5 people, Wout waited at he back (essentially a `-==` formation) until the last ~5km, and dropped Pogacar at the climb, then extended nearly a minute difference until the finish.
My fave youtube echelon analysis - https://www.youtube.com/watch?v=5wmGp2pKF60
I doubt this practical value exists. The paper completely forgets one important element¹: having a single rider at the front saves the energy of the teammates. If a team was to put two riders upfront and then the chase takes more time than expected, they have no backup. And even if the strategy was to succeed and the leader gets back into the peloton, he/she will have two tired teammates instead of one, which means a reduced help for the remaining of the stage.
I also suppose pro teams already know all of this, even if they didn't have the precise benchmarks of this paper. It's just unpractical most of the time. For a diamond shape, the aerodynamic gain is pretty obvious, but with a high price to pay in order to protect a rider.
As a side note, the paper authors should learn about PDF metadata. It's quite ugly that the file's title is "Microsoft Word - 2025_Preprint_Formations_V2".
[¹]: Except when they quote a cycling specialist about the goal to "reduce the leader's effort without sacrificing too many team members".