steepest hills

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Ken Roberts
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steepest hills

Postby Ken Roberts » Mon Aug 17, 2009 2:00 pm

We had a little discussion last year about riding versus skiing up steep hills.

Since then I found a credible case of people riding their bicycles up a paved road about 35-40 vertical meters at steepness around 31% grade, namely Fargo St (just east of the Glendale freeway in Los Angeles, California).

31% grade. What struck me was that in the photos it didn't like the riders were any sort of pros. Seemed like local athletic riders who had gotten good at "tacking" up a steep hill -- riding a zig-zag path with big curves -- and the street looked decently wide and decently smoothly paved.
    I've ridden about that much vertical at 20% grade going straight up the hill, so I guess I could ride up 31% if I practiced "tacking"(?)

How steep are some of the trails people ride up on mountain bikes?

What are some of the steepest sections of trail on some cross-country ski courses?

I think it's pretty well established that there's no asphalt road in the world at least a block long that's as steep as 40% grade.

Ken

kuan
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Postby kuan » Mon Aug 17, 2009 3:28 pm

Have you watched Russian Hill Roulette? (the film)
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Ken Roberts
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Postby Ken Roberts » Tue Aug 18, 2009 2:27 pm

kuan wrote:Have you watched Russian Hill Roulette?

I'd never heard of Russian Hill Roulette -- thanks a lot for the suggestion.

Looks like that guy's approach is just to sprint straight up through the steep part of each hill. Which I guess works because (a) he's stronger than me; (b) the super-steep parts of those hills in San Francisco are not as sustained as Fargo St in Los Angeles.

This video of the annual Fargo St climb event shows three approaches: (1) straight up; (2) tacking side to side; (3) ultra-low gear.

The ultra-low gear video suggests that maybe a human actually could pedal up a sustained paved hill at steepness 60% grade, on a specially-designed bike (designed not only for low gearing but also for balance) on excellent asphalt or concrete.

"Tacking" definitely changes the game. In the limit it can be made into a sequence of (sharply curved) micro-sprints separated by rests in track-stand (with the wheels even across the hill). If you're balance is good enough, there's no limit to how slowly you could go up the hill.

(4) (not shown in the video) No pedaling at all. Just repeatedly jump the bike sideways up the hill.

Ken


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