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question about drafting and pulling(6 posts)

question about drafting and pullingwolfereeno
Aug 1, 2002 1:44 PM
Listening to the announcers during the Tour coverage, they made it sound like when someone attacks and is caught, the person behind them slows them down. That doesn't make sense. If anything I'd imagine that perhaps in some extremely small way they're filling the void of air left in your wake that pulls back on you.

So is the person sitting on your wheel actually slowing you down or is it just psychological? i.e. they've shown that they're just as fast as you and since they're drafting you now, in the long run they have an advantage.

Thanks
I think it's more that getting caught deprives you of yourbill
Aug 1, 2002 2:13 PM
incentive to go faster, because then all you're doing is working hard to pull along your adversary instead of breaking away. Although plenty often the catchee slows to make the cather now do some of the work, what you also sometimes see, particularly close to the line, is the cathee zig-zagging like crazy trying to shake the wheelsucker. If I understand this correctly, if the catchee can shake the catcher, they're now back on more even footing, and the catchee has another chance to break away (or at least not lead out his wiley and worthy adversary in the sprint).
slowing downvelocity
Aug 2, 2002 5:55 AM
In order for a pursuer to catch a rider in a breakaway they have to go faster than that rider. When a pursuer has caught a breakaway, and grabs onto a caught rider's wheel, he has to slow down a bit.
I swearfiltersweep
Aug 4, 2002 6:20 AM
I swear that I can "feel" someone "grab" my wheel. With the wind through the helmet, I can't really hear them, so there is no other explanation, but when I pull, it actually feels like I'm pulling (ever so slightly). After a while, pulling just feels normal, but going from riding solo to pulling, it seems very noticeable.

BTW- in the long run the leader often has the advantage over a solo chaser unless he is completely "out of gas.". The chaser needed to exert more energy by riding faster to catch up. They recover by riding your wheel. It isn't about showing "that they're just as fast as you" since it is really about having enough energy at the right time (they are all fast). A long race is about resource management. In the Tour, as you probably saw many times, a member has much better odds of winning a stage if he is part of a breakaway GROUP, since they can work together to stay ahead of the peleton, then they all roll the dice at the sprint. A solo breakaway is usually a recipe for disaster, and in the tour, some folks took a few days to really recover.
Yes, it does create dragshirt
Aug 8, 2002 1:58 PM
Somebody sitting on your wheel does create drag. Not that noticeable, but it's there.

In a more extreme example, I used to road race motorcycles. Going down the straightaway, you can feel somebody right on your tail; there's a 'pulling' sensation that's quite evident.

You can actually use the draft of the rider in front of you to create a vacuum that sucks you right up to their rear wheel, then at the last moment you pull to the side and get catapulted by. During this "catapult" you can actually exceed your max speed for a moment; i.e., if your top speed (alone) is 152 @ 14,200rpm, you'll briefly see 155 at 14,300rpm. As you pass the passee, they are literally sucked BACK into their own vacuum. I don't know the physics of this at all; I just know that's what happens.

All that blabbering is simply to illustrate the point the having somebody on your tail does create a physical disadvantage, however slight at the speeds bicycles climb...
no, no, noDougSloan
Aug 9, 2002 5:37 AM
You contradict yourself.

Someone drafting fills the negative pressure area behind the lead rider, lessening the drag on the front rider a tiny bit. The front rider can go faster with someone behind.

You actually demonstrate this in your illustration. You state that once you pass, the former lead rider gets "sucked BACK into their own vacuum." What you are saying is that until the pass, the drafting rider was filling that vacuum. When that vacuum is no longer filled, there will again be more drag.

A lot of this is psychological, though. If I know someone is sitting in and not pulling, I'm less inclined to bust my butt and pull him along faster. I'll slow, hoping he'll take a pull.

Bottom line, though, someone behind you makes you faster, not slower.

Doug