Question on gear ratios

jnovakone said:

Does anyone have a formula for comparing gear ratios? I used to have one years ago, however, I cannot remember it. It involved comparing the numer of teeth on the crank with the cassette and wheel size. I currently have a hybrid with mountain bike gearing and I am thinking of purchasing a hybrid with road bike characteristics. Would like to get an idea of how the change in gearing would match up. Thanks!

There is a gear inch calculator in Sheldon Browns stuff at www.harriscyclery.com another one at www.bikeschool.com

boudreaux said:

There is a gear inch calculator in Sheldon Browns stuff at www.harriscyclery.com another one at www.bikeschool.com

Thank you for the quick response, just what I was looking for!

This gear roll out (development) chart is also useful:

http://www.analyticcycling.com/PowerMeasAnalyGear_Disc.html]
(scroll down)

The old inches calculation, i thought, was:

(Chainring teeth #, divided by cog teeth #) x 27 = inches

nutbag said:

This gear roll out (development) chart is also useful:

"]http://www.analyticcycling.com/PowerMeasAnalyGear_Disc.html]
(scroll down)

The old inches calculation, i thought, was:

(Chainring teeth #, divided by cog teeth #) x 27 = inches

That's the one!