7 replies to this topic

[jischr]

My daughter and  I were watching Le Tour and she had a question I couldn't answer since I don't race.   Why draft on a mountain stage?  I understand the idea of someone setting the pace on a climb to drop the weaker riders.  But when Phil says so-n-so has done their job pace setting and is now dropping back, job well done, why aren't the others wasted?  They're fighting the same grade at the same pace. Are they really going up a mountain fast enough that air resistance is a factor?  I didn't think aerodynamics had much influence below 18 mph.  Or are they looking for that 1% of effort reduction that lower speed drafting would provide?

[illinihand]

I have heard that once you are over 12 miles per hour that aerodynamics really plays into your riding. So if you were doing a TT and you were going up a hill, it is better to stay in your aero position until you drop below 12mph. Same with going uphill. Even though you are going up the same grade the man in front is still giving a draft as long as you are going fast enough.

This is an article by local-ish (CoMO) guy Dave Henderson about aerodynamics. He says that 10mph is the speed in which aerodynamics becomes important so I would go with that over what I heard.

http://myworldfromab...-how-to-be.html

[Mark EWERS]

Reducing drag by 30% at 12 mph will save a rider about 15 watts ascending an 8% grade.

[Jetmugg]

... and if those guys are only going 12 mph up an 8% grade, they are OFF THE BACK.

[S&M]

plus, I suspect it can be psychologically easier to sit on a wheel than it is to set the pace, unless you're feeling uber-strong and are ready to dish it out.... Not sure if science backs that up, though.

[tarmac72]

it's pacing not drafting
and a nice soft cuddly feeling
lock your gaze on that wheel and don't let go

[jischr]

On the web site that Illinihand linked there is another post called " Dude your crank length's fine".  It includes the PowerPoint file 'Myth and Science in Cycling.'  The author's recommendations for drafting states drafting on climbs is important even on steep ones.  So I guess when I come up on a turtle while riding at Babler I'll let him pace me up.  

[oldfatguy]

jischr, on 17 July 2012 - 06:35 PM, said:

Are they really going up a mountain fast enough that air resistance is a factor?  

Yes.