Re: [CR]Crank length, today and yesterday


Example: Events:Eroica
In-Reply-To: <12.12b639b2.28dbf95d@aol.com>
References: <12.12b639b2.28dbf95d@aol.com>
Date: Thu, 20 Sep 2001 22:27:17 -0400
To: LouDeeter@aol.com, classicrendezvous@bikelist.org
From: "Sheldon Brown" <CaptBike@sheldonbrown.com>
Subject: Re: [CR]Crank length, today and yesterday


LouDeeter@aol.com quoted me thus:
>"This is a common misunderstanding. The "leverage" of a bicycle drive
>train, also known as "gain ratio" depends on the crank length, wheel
>diameter and the sizes of both sprockets."

and wrote:
>May not be leverage, but if I'm in a 39x26 gear with no lower gear, then that
>172.5 crank sure feels better on a steep hill to me than a 170. If you don't
>change gears, then I just believe that if the lever arm is longer, then the
>force being applied at the pedals will create 'leverage'. At least that is
>the way the physics works for me. Lou Deeter, Orlando FL

That's true, but if you need a lower gear than 39/26, you can get it easily and cheaply by installing a different cassette or chainwheel without messing with the biomechanics of your knees. Most bikes these days have much lower gears than that available, and yours should too if that isn't low enough to suit your needs.

Sheldon "That's What The Gears Are For" Brown Newtonville, Massachusetts +-------------------------------------------------------+ | Military conscription is the worst form of slavery. | | A more enlightened age will consider it a War crime. | +-------------------------------------------------------+
      Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772, 617-244-1040, FAX 617-244-1041
            http://harriscyclery.com
       Hard-to-find parts shipped Worldwide
            http://captainbike.com
    Useful articles about bicycles and cycling
            http://sheldonbrown.com