Everyone,

Here is a link to a very useful gear-inch calculator that can be used when designing a drivetrain incorporating "intermediate" chainwheels or freewheels.

http://www.ihpva.org/Projects/tstrike...

Suppose a certain Evil Genius wanted a low gear resulting in say, nine gear-inches. And he planned to use a standard crankset up front, driving an intermediate freewheel, that then drove a second freewheel or cog that was actually connected to the wheel/tire. This program would allow the Evil Genius to input various chainring and cog combinations (in # of teeth) and would output the result in gear-inches! OK, some of you know exactly what I just said. If you didn't, its time to get Googling. The late-great Sheldon Brown published many web-articles and bicycle-dictionaries that explain what the parts are and what they are intended to do. How you misuse, uh... re-purpose them is up to you.

Dr. scott Diabolical