"Carl Fogel" <

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> "Dale Benjamin" <

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> > "Mark Hickey" <

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> >

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> > > "Dale Benjamin" <

[email protected]> wrote:

> > >

> > > >My gut always told me that an optimized top end gave

> > > >more gain than

an

> > > >optimized low end, loaf going up hills because one

> > > >doesn't gain or

lose

> > much

> > > >time or distance anyway, but really work going down,

> > > >one gets better

> > cooling

> > > >at speed, and gains more.

> > >

> > > Your gut lied. ;-)

> > >

> > > You lose a lot more time by taking it easy going up

> > > than you do going down.

> > >

> > > When you're going up, putting out 25% more power will

> > > result in you going nearly 25% faster - or going 25%

> > > further in the same amount of time.

> >

> > 125% 0f 6 mph is 7.5 mph. Big deal.

> >

> > > If you put that same extra effort into a fast gravity-

> > > aided descent, you'll go only slightly faster (since

> > > aerodynamics will be the chief force to overcome). For

> > > example, according to the excellent calculator at

> > >

http://www.analyticcycling.com ...

> > >

> > > If a typical cyclist was descending a 10% hill, and

> > > putting out 100 watts, they'd hit a speed of just

> > > under 80km/h (or, 50mph).

> > >

> > > Increase their output to 125 watts, and the spead

> > > "leaps" by a whopping 0.16km/h (or 1/10th of 1mph).

> >

> > I haven't found any hills where 50 mph was realizable,

> > once I got over

40

> > mph. Something like 35 mph was generally a pretty good

> > top speed on any hill around here.

>

> Dear Dale,

>

> Actually, that pitiful 1.5 mph difference works out to a

> huge deal in practical situations.

>

> At 6 mph, a six-mile climb takes 60 minutes.

>

> Now strain yourself to 7.5 mph uphill on the same 6 mile

> stretch. True, this is only 1.5 mph faster, but it's also

> a 25% speed increase.

>

> You reach the top in 48 minutes, 12 minutes sooner.

>

> At 30 mph back down the hill (I slowed your descent to

> make the arithmetic simple), you cover a mile every two

> minutes, so your descent takes 12 minutes.

>

> So the 7.5 mph rider finishes the whole 12 mile ride in

> 60 minutes, just as the 6 mph rider reaches the top. A

> six-mile lead on a twelve-mile ride could be called a

> big deal.

>

> It's also the explanation for most of Armstrong's

> advantage in the Tour de France. He keeps up fine on

> normal riding, does well on the individual time trial, and

> goes maybe a mile an hour faster up those ugly mountains

> than whoever's in second place.

>

> It's a matter of how far, how long, and what the relative

> speeds are. The 7.5 mph rider is 12 minutes faster per

> hour than the 6.0 mph rider.

>

> To gain the same 12 minutes per hour downhill, you have to

> go 37.5 mph against someone going 30 mph--and find a place

> where you go downhill that fast for an hour, which is

> much, much harder than finding a place to trudge uphill

> for an hour.

Your numbers seem realistic and I can't argue with the

arithmetic, you're entirely correct. Like someone wrote

before, there will be less gain at higher speed for the same

increment of power, so the first guy will probably have an

even larger lead. I don't suppose any realistic

quantification of heat effects on riders in various physical

conditions is feasible, but I think this may sometimes be

significant. Supposing both riders are in the same physical

condition, the one who works harder going uphill will fail

before the one who works harder going down, because their

body will become overheated.