Question: Drafting effects on lead rider?

Bro Deal said:

Over in the TdF racing forum a question has come up. Does the lead rider get an aero benefit from being drafted?

It seems to me that bikes travel too slow and the wheels prevent followers from getting close enough, but I have heard his from various people. Does there exist any real world research that has measured a benefit? I cannot seem to google anything other than people attributing the benefit achieved in motor sports to bicycles.

If there is a benefit then how large is it?

Yes, there is a benefit. Vision Quest Coaching (owned by Robbie Ventura, Chicago, IL) had an aerodynamics clinic and was able to test this concept on a track. A rider with a K factor of 0.165N/m was able to reduce their drag to 0.13N/m by having a rider draft behind him. This was at a constant power of 250 watts on a 186lb rider+bike.

iliveonnitro said:

Yes, there is a benefit. Vision Quest Coaching (owned by Robbie Ventura, Chicago, IL) had an aerodynamics clinic and was able to test this concept on a track. A rider with a K factor of 0.165N/m was able to reduce their drag to 0.13N/m by having a rider draft behind him. This was at a constant power of 250 watts on a 186lb rider+bike.

Yup. The problem with aero drag is not so much how much area you present to the wind but how the airflow behaves after it goes around you. That's where the drag is coming from. So instead of becoming so turbulent behind you and becoming a "drag," the airflow stays a bit smoother and flows over the second rider.

iliveonnitro said:

Yes, there is a benefit. Vision Quest Coaching (owned by Robbie Ventura, Chicago, IL) had an aerodynamics clinic and was able to test this concept on a track. A rider with a K factor of 0.165N/m was able to reduce their drag to 0.13N/m by having a rider draft behind him. This was at a constant power of 250 watts on a 186lb rider+bike.

That would be a huge improvement. Like 21%. Is that right? The only stuff I could find on the Internet theorized a 3% reduction.

Bro Deal said:

That would be a huge improvement. Like 21%. Is that right? The only stuff I could find on the Internet theorized a 3% reduction.

Exactly..it can be huge. Obviously 21% is ideal, but double digit percentage increases are easily obtained by having anyone draft behind you.

Robbie Ventura? 😄 Yeah there is someone who knows how to perform a controlled experiment... please, that joker couldn't even control a standard doping protocol for his boy...

Here read this thread and the links as well which indicates benefit is small enough that there is some serious debate as to whether it is measurable at bicycling speeds.
http://biketechreview.com/phpBB2/viewtopic.php?t=1621

wilmar13 said:

Robbie Ventura? 😄 Yeah there is someone who knows how to perform a controlled experiment... please, that joker couldn't even control a standard doping protocol for his boy...

Here read this thread and the links as well which indicates benefit is small enough that there is some serious debate as to whether it is measurable at bicycling speeds.
http://biketechreview.com/phpBB2/viewtopic.php?t=1621

An energy or power reduction of 2-3% is significant.

As for your Robbie Ventura knowledge....well, it's as valuable as anyone else's opinion. Feel free to offer objectivity.

wilmar13 said:

Robbie Ventura? 😄 Yeah there is someone who knows how to perform a controlled experiment... please, that joker couldn't even control a standard doping protocol for his boy...

Here read this thread and the links as well which indicates benefit is small enough that there is some serious debate as to whether it is measurable at bicycling speeds.
biketechreview.comviewtopic.phpOpen ↗

I said he owned the company, not that he did the experiment, jackass.

An engineer who is an assistant coach for Robbie did the experiment.

alienator said:

An energy or power reduction of 2-3% is significant.

Agreed... problem is even that 2-3% is based on a CFD... data from Kyle's published article shows no drag reduction for lead rider, yet for the popular press he claims 2-3%... Either way double digit % reduction of drag for lead rider is pure [censored].

At the end of the day who cares if you are getting a 2% or a 0% reduction in drag, when you are tired flick your arm and have the lazy bugger on your wheel pull though so you too CAN get some double digit drag reductions.

iliveonnitro said:

I said he owned the company, not that he did the experiment, jackass.

An engineer who is an assistant coach for Robbie did the experiment.

I just got an email back from the guy who ran the experiment and this was actually the 4th test for this particular rider. They were adjusting positions at the aero clinic and were able to reduce the drag in this riders position and bike by ~15-16% over the additional 2 trials. It was the 4th test that succeeding in obtaining the 21% improvement from the 1st. This shows ~5-6% improvement by having someone draft behind you under controlled conditions.

Sorry for the initial mishap in communication, but at least it's still higher than the previous 2-3% that was estimated.

iliveonnitro said:

I said he owned the company, not that he did the experiment, jackass.

An engineer who is an assistant coach for Robbie did the experiment.

Relax no need for name calling, sorry I made a joke at the expense of your favorite rider, Roid Landis.

Either way I don't care who did the experiment. The results don't jive with everything else out there so I don't think a little healthy skepticism is wrong.

I don't understand the units you quoted. In addition to being a jackass, I guess I am a [censored] for thinking N/m is newton meters which is torque which makes no sense in this context. 😕

wilmar13 said:

Relax no need for name calling, sorry I made a joke at the expense of your favorite rider, Roid Landis.

Either way I don't care who did the experiment. The results don't jive with everything else out there so I don't think a little healthy skepticism is wrong.

I don't understand the units you quoted. In addition to being a jackass, I guess I am a [censored] for thinking N/m is newton meters which is torque which makes no sense in this context. 😕

And PS, Robbie never had anything to do with Flandis doping...you can blame Phonak for that [censored].

iliveonnitro said:

Sorry for the initial mishap in communication, but at least it's still higher than the previous 2-3% that was estimated.

Yes this anecdotal result is higher than the estimate... my point was that under conditions that wouldn't get a research paper thrown out by a teaching assistant there was no measurable benefit... so then the author "estimated" 2-3%. It is hard to totally control for all the variables but there is no debate it is much better to not be the guy in front even if there is some ambiguity of the benefits to having someone on your wheel. 😉

wilmar13 said:

Relax no need for name calling, sorry I made a joke at the expense of your favorite rider, Roid Landis.

Either way I don't care who did the experiment. The results don't jive with everything else out there so I don't think a little healthy skepticism is wrong.

No doubt your expertise in aerodynamics leads you to your valued conclusions, right?

You know, there is actually value in wanting to know something just for it's intellectual value, as an intellectual exercise, to expand the wealth of human knowledge, and other things you might not have been told about in class.

Roid Landis: what a pathetically lazy stab. You really are a mental giant.

iliveonnitro said:

And PS, Robbie never had anything to do with Flandis doping...you can blame Phonak for that [censored].

No the blame lies solely on Roid.

alienator said:

No doubt your expertise in aerodynamics leads you to your valued conclusions, right?

WTF? I posted a link to other viewpoints, studies, and a dialog.

alienator said:

You know, there is actually value in wanting to know something just for it's intellectual value, as an intellectual exercise, to expand the wealth of human knowledge, and other things you might not have been told about in class.

Of course there is, you are preaching to the choir. 😕

alienator said:

Roid Landis: what a pathetically lazy stab. You really are a mental giant.

Again, WTF is your problem? 😕

wilmar13 said:

Again, WTF is your problem? 😕

One guy makes a statement re: the thread topic, then you respond with an inane statement about Landis and favorite riders. Really, is that how it works?

Aw, man... I'm obviously a bit too late to this thread. I was going to talk about airflow, turbulence and stuff, but it's already degenerated to talking about Landis...

Anyways. Empirically, you know that drafting does benefit the riders up front. Otherwise the pack leading up to a bunch sprint wouldn't be able to sustain 60 km/hr for the last 10 km. And no, it's not because people are rotating through. People are fighting to get up front and stay there.

John Swanson
www.bikephysics.com

Huh? It was a joke… and quite obvious at that. And that somehow justifies your dickish responses on this thread? The same guy that writes:

alienator said:

Yup. The problem with aero drag is not so much how much area you present to the wind but how the airflow behaves after it goes around you. That's where the drag is coming from.

then acts condescending about another posters understanding of aerodynamic drag? LOL

ScienceIsCool said:

Aw, man... I'm obviously a bit too late to this thread. I was going to talk about airflow, turbulence and stuff, but it's already degenerated to talking about Landis...

Sorry I made the joke about Landis... clearly it is too sensitive to joke about.

ScienceIsCool said:

Anyways. Empirically, you know that drafting does benefit the riders up front. Otherwise the pack leading up to a bunch sprint wouldn't be able to sustain 60 km/hr for the last 10 km. And no, it's not because people are rotating through. People are fighting to get up front and stay there.

John Swanson
www.bikephysics.com

Sorry man, I disagree... no one is staying on the front for the last 10K they are near the front but not the leading rider... besides even if they were, I can ride on my own for almost 1K at 60km/hr and I am not a pro cyclist (just a strong local racer). It only takes about 750 watts to maintain that speed on level roads with calm conditions. Much less just sitting 2nd wheel.