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-   -   Does drafting slow down the rider in front? (http://www.bikeforums.net/general-cycling-discussion/110665-does-drafting-slow-down-rider-front.html)

SasquatchSooner 05-31-05 12:14 PM

Does drafting slow down the rider in front?
 
My wife tells me it can be as much as 20% easier for a rider that is drafting someone in front of them. So I asked her if is more difficult for a rider that is being drafted as opposed to not being drafted. She didn't know the answer but thought it would not be any more difficult. I tend to think it would be more difficult for someone who is being drafted. Anyone know the answer?

Sprocket Man 05-31-05 12:25 PM

Drafting does now slow down the rider in front. But having a rider draft behind you without taking a turn in front can be psychologically draining. It's a common tactic used in road racing.

Keith99 05-31-05 12:38 PM

Actually having a rider sit behind helps the rider in front. There is actually drag from the turbulance behind you. Now this benefit is far less than that for the trailing rider and if you do not trust the rider behind the stress created can be far more draining than the physical advantage gained.

phidauex 05-31-05 12:39 PM

EDIT: What Keith said. ;)

No, drafting doesn't slow down the front rider, and in fact, should give them a slight benefit, because the other rider prevents the airstream moving over them from going turbulent behind them, which can cause low pressure areas that slow you down. In cycling it is a pretty subtle effect, but its noticable in other aerodynamic fields.

Psycholocially, it is a bit draining to have someone that close to you that you can barely see, and if the two people aren't trading off, it can be a little annoying. Drafting certainly isn't fair in time trial type of events, and can be dangerous in other cases, which is why some types of races forbid it.

peace,
sam

Da Tinker 05-31-05 12:42 PM

There is test data showing that the trailing rider keeps the 'streamlines' open behiind the lead rider, thus preventing the formation of a low pressure 'suction' area. For cycling, the benifit is low, only 2-4% of the total energy. I've felt it under ideal conditions.

SasquatchSooner 05-31-05 12:54 PM

Interesting. Sounds like my wife's thoughts were closer to the truth than mine (again). Thanks for the insight.

RockinAR 05-31-05 06:45 PM

Not sure about cycling, but in auto racing drafting helps both the drafter and draftee. When you draft someone in auto racing you create a low pressure situation in the rear of the vehicle. That means there's less downforce on the rear of the vehicle so vehicle can go faster, and thus pulling the drafter around with him.

boyze 05-31-05 06:52 PM

Another way of saying what's already been said is that two or more riders increases the L/D ratio of the body cutting through the air, with L being the length and D being the frontal area.

CdCf 05-31-05 07:23 PM

L/D ratio is normally understood to stand for Lift/Drag... :)

The rider in front does gain, yes, but I seriously doubt anyone would be able to feel it.

skydive69 05-31-05 07:43 PM

On another subject, a very experienced rider/racer that I know told me that riding in a long pace line, the last man can actually be doing as much as if not more work than the guy pulling. This is due to the turbulance. I need to look into this further.

Trsnrtr 05-31-05 08:02 PM

Quote:

Originally Posted by skydive69
On another subject, a very experienced rider/racer that I know told me that riding in a long pace line, the last man can actually be doing as much as if not more work than the guy pulling. This is due to the turbulance. I need to look into this further.

I've experienced this on a tandem several times in strong quartering tailwinds but rarely on a single. I always assumed the turbulence was wreaking havoc with all of the tubing that a tandem has as well as the two pairs of legs. Anyway, the only option when it happens is to stay near the front of the paceline or do most of the pulling.

Wurm 06-01-05 03:51 PM

Quote:

Originally Posted by CdCf
The rider in front does gain, yes, but I seriously doubt anyone would be able to feel it.

If the "2%-4% benefit" figure is true, then that can be significant to the front rider over long hauls. You may not feel it right away, but you'll be able to maintain speed longer than when riding solo.

Da Tinker 06-01-05 04:02 PM

And it's more fun riding with a friend!


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