I wanted to both expand this question and bump it since I'd like to know the answer, too. One of the commentators said that it would take about 9 minutes to cover the last 3km of a climb. That works out to 12 mph if my math is correct. How much help does a rider really get by following someone at this pace?

Even at my pathetic speeds up 7% climbs on my computrainer there is still a 3-5% savings when I sit on the pacer. Even 1% would be an advantage at the top of the sport. The final standings in the major Tours are generally not much over a 3% difference top to bottom so it all adds up.

I'm 99.9% sure it is much more psychological than aerodynamics. At that speed, aerodynamics dont play an important role. I have climbed at the same pace with much more ease when sitting on someone's wheel, just staring at their hub or something. When climbing this way, I kinda zone out and just focus some part of their bike. Then, before you know it, you are at the top of the climb (well, maybe not that easy, but...) I cant explain it, but getting pace up make climbing easier than setting your own pace.

Give it a try sometime. Ride up at a particular pace (I think LT would be a good intensity), say a 1-2 mile, 7-9% grade climb, with you leading... then another day, try it again but have someone pace you up but at the exact same speed. I'm willing to bet that once you get used to it, your Perceived Exertion and HR will be lower when you have someone pacing you up.

Of course, this doesnt do anything for non-draft legal triathlons.

wilson

Remember that most of these long climbs have various moderate-to-flat bits, too. Riders might average 10-12 mph, but they are running in a range from 8-20+ mph at various points. Drafting pays anywhere above about 12 in my experience.

And -- as someone else pointed out -- there is an advantage to following someone else's pacesetting, but only to a point. Someone can set too fast a pace and you can blow up.

I definately agree with the other person that posted that there is a definate psychological advantage sitting on someones wheel. When you feel like easing up it helps to have the extra incentive of staying on someone's wheel.

"I'm 99.9% sure it is much more psychological than aerodynamics."
I want to mention the often-neglected point that aerodynamics has to do with speed relative to the air, not speed relative to the ground.
Suppose there's a 20 mph headwind... your psychology would have to be pretty effective to match the aerodynamic benefit of drafting in that case!
Suppose there's a 20 mph tailwind... obviously it will be more psychological than aerodynamic.