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Frame geometries and frame purpose(2 posts)

Frame geometries and frame purposecollinsc
Feb 12, 2003 10:24 PM
So there is a post a bit down the page requesting suggestions on a good cheap climbing bike.

You always hear talk of seat tube angles, setback and what not, how it makes for more power or something. Terms like "relaxed" are also thrown around with abandon.

What makes a climbing bike a climbing bike? (and I dont want to hear and dumbass "its not about the bike" comments. What do differences in geometery minutia mean towards the purpose of the bike?

Some people cite short chainstays as a good characteristic of a climbing bike. Why? Shorter wheelbase? What does that matter when headed up a hill?

re: climbing bikesFredrico
Feb 13, 2003 2:20 PM
Short chainstays put the wheel under the rider, good for traction. They also shorten the distance from the crank to the rear wheel, increasing the efficiency of the transfer of power.

A bike with upright seat angle, 74-75 degrees, puts the weight of the rider up over the crank, which increases bodyweight to the downstroke, useful fighting a hill, especially when you consider the steeper the hill is the furthur back you are from the crank.

I guess having a steep headtube is good, too. It brings the front wheel in towards the center of gravity.

But mainly, a good climbing frame is stiff, especially around the bottom bracket and rear triangle. Frame flex from the crank to the rear wheel soaks up alot of energy.

My .02. Others might add valuable experience. I've never had a "climbing bike," just a plain old steel racing bike. It's always climbed really well--when I'm in form!