During a race on Sunday I got over taken by the lad who went on to set the quickest bike split. I let him pass once he was 20 metres or so infront I kept pace for a few minutes until I realised what I was doing and let him go. I think for me to ride at his pace would have required about 20watts more at least at the pace he was riding at the time. If I had ridden behind him at the legally required distance (as you see the pro’s do in 70.3 and IM races) how many watts would I have saved? This rider rode about 14mins quicker than me so I think even with some watts saved I would have had a tough time staying anywhere near him. I think I would also be to worried of getting into the draft zone to get close enough to get any benifit anyway, but I wonder how much assistance riding like this gives (if any other than pacing).
Supposedly the second person in line can save around 22% and the third wheel saves about 30%. (Can’t remember where I saw that though.) But you get nothing by 20m I’m sure.
22% at 7 meters???
no, try inches
Those numbers are for a paceline
.
Not the answer you want I’m sure, but I think it depends.
It depends on the conditions, ie wind.
My example. When riding solo with a slight tailwind, I notice when a big truck in the opposite lane (coming at me) seems to deliver a much less wind impact. I assume the tailwind I am riding in offsets somewhat the push of air the truck creates. Alternatively, when riding in still conditions, the same truck makes much more of a hit of wind on me because there is no tailwind to buffer the truck’s effects.
Soooo, if you are 7m behind someone in still conditions, the gap of air they open up may be much more substantial (thus more benefit) than if you both are riding in a headwind.
I know this is simplified quite a bit, actual wind is really vortex’s and various turbulent patterns, but the gross effect is what I am noting.
i think you can find that info in SRM’s webpage somewhere. I remember reading about Faris pulling the pack at Kona and I think it was Luke Bell was 7M behind and he averaged less Watts than Faris and they said this despite the fact that Luke is bigger and weighs more than Faris. But i don’t remember the exact number I think Faris averaged 283 and luke bell like 273 or something like that. But you have to remember they are biking much faster.
ok I found it:
Faris averages the same power he achieved when he won in 2005: 283 Watts. His cadence was a bit lower this year averaging 81,7 RPM. The race separates again in two pieces. High power on the way to Hawi, averaging 301 W in the first half and a drop to 267 W in the 2nd half. It is visible from Faris’ data that 7 meters distance between the athletes isn’t enough to avoid drafting effects. Luke Bell, who was riding in a group in Faris’ wake, especially in the 2nd half of the race, needed remarkably less power for the same speed. Comparison of the average power output proves that as much as comparing the mechanical work expressed in energy: Faris burned 4592kJ (mechanically) vs. Luke who spent 164 kJ less despite being taller and (2kg) heavier. Our spotter who followed the leading men, confirmed what we measured. The true shootout on the bike took place between Normann at the front and Faris behind him.
this is where I got it from:
if you are going to post that worthless drivel from 2peak here again, then i am going to re-post my analysis from last october:
"There has been a lot of banter back and forth about how much drafting there was in the lead pack at IMH. The prime example has been that Luke Bell’s average power for the second half of the ride was “remarkably” less than Faris, using the first half of the ride as a reference point. I just don’t see the “remarkable difference”
Faris’ Ride-- 1st half 301 watts; 2nd half 267 watts
Luke’s Ride-- 1st half 295 watts; 2nd half 251
Therefore Luke’s power output was 98% of Faris’ power output for the first half and it was 94% of Faris’ for the second half. We don’t have any data regarding normalized power, and during the coverage Faris was visibly pedaling downhill, while Luke was in a tuck and coasting. The course profile coming back from the turnaround could account for the difference.
I am not saying Luke did not benefit from “sitting it”; however, I am saying there is not nearly enough data to make the claim he had more of a benefit in the 2nd half of the ride than he did in the first half of the ride. I think the people at 2Peak should do a more in-depth analysis before they go out claiming Luke was surely drafting during the second half. There is further evidence more analysis is needed when you look at Luke’s cadence. His average for the first half was 86, and it was 80.8 for the second half. It looks like he may have done some coasting during the portion after the turnaround, as his cadence drops there, but then it goes back to normal levels later. Having 0’s in your cadence and Power will certainly alter the data enough to make it look as if he was draft when in fact he was conserving energy on the downhills by being more aerodynamic. Don’t crucify the guy…he sounds like a pretty smart rider."–Me
i just posted it cause i had read it. I was not at Kona, but from the video it does look like they are all trying to catch a draft. Also on a down hill if you don’t pedal and you are in on the train you usually have to brake or you will catch the guy pulling you. in this case Faris was pedaling down hill and I am sure luke was just sucking the wheel even at 7M. because if Luke was coasting on the down hills and he was in the pack then he must have been getting a pull because As you state Faris was peddaling down hill. If Faris wasn’t pedaling and luke was at 7M even with a little bit of draft and weighing more than Faris he would have passed him on every down hill.
But what do I know. that is just the info I read on 2peak like you said.
How much it helped him who knows.
Its an interesting one I am sure someone did something in a windtunnel that predicted a recordable benifit even at the legal distance.
Hello Boing and All,
USAT recognizes a practical benefit in drafting at 7 meters and establishes a larger (10m) distance for Elites.
There are many variables for drafting, yaw angle of wind, cyclist speed, and so on, so quantifying specific instance drafting benefit is not a trivial task.
Cheers,
Neal
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b. Definition of Drafting Zone. The term “drafting zone” shall refer to a rectangular area seven (7) meters long
and two (2) meters wide surrounding each bicycle. The longer sides of the zone begin at the leading edge of the
front wheel and run backward parallel to the bicycle; the front wheel divides the short side of the zone into two
equal parts. With respect to a moving motor vehicle, the “drafting zone” is a rectangular area extending 15
meters to each side of the vehicle and 30 meters behind the vehicle.****
==========================================================================
5.10A Position Fouls. Rule for Elites
(a) Illegal Positioning. Except as otherwise provided in these Rules, while on the cycling course, no participant
shall permit his drafting zone to intersect with or remain intersected with the drafting zone of another
participant or that of a motor vehicle. With respect to a motor vehicle (including authorized race vehicles), it is
the athlete’s responsibility to continually communicate to the vehicle to move away.
(b) Definition of Drafting Zone. The term “drafting zone” shall refer to a rectangular area ten (10) meters long
and two (2) meters wide surrounding each bicycle. The longer sides of the zone begin at the leading edge of the
front wheel and run backward parallel to the bicycle; the front wheel divides the short side of the zone into two
equal parts… With respect to a moving motor vehicle, the “drafting zone” is a rectangular area extending one
meter to each side of the vehicle and fifteen (15) meters behind the vehicle.
(c) Exceptions. A participant may enter the drafting zone without penalty only pursuant to the following
exceptions:
(1) When entering the drafting zone form the rear, closing the gap, and overtaking all within no more than 15
seconds; or