Now there's one problem with all of this. The right hand thread on a BB is usually on the left which means the cassette won't screw on so you will need to improvise. You could either re-fit the BB the other way round, re-thread the tube or weld a right hand thread cone to the outside of the right one.
How to calculate gear inches with an
intermediary gear
Date: Sun, 9 Jul 2000
From: Charles Mantey
With an intermediary gear you just need to add another
ratio to the gear forumla.
Standard Gear Formula:
Gear Inches = (Drive Wheel Diameter) * (Front
Teeth)/(Rear Teeth)
With an Intermediary gear the formula become:
Gear Inches = (Drive Wheel Diameter) * (Intermediary
Teeth)/(Rear Teeth) * (Primary Teeth)/ (Intermediary
Teeth)
So lets say you have the following:
Drive Wheel is 26 inches in diameter Rear Gear is 32
teeth Intermediary gear is 30 teeth Primary gear at the
cranks is 26 teeth.
Gear Inches = 26 * 30/32 * 26/30 = 21.125 Gear Inches.
Sheldon Brown has a nice explanation about gear inches at
http://www.sheldonbrown.com/gloss_g.html#gearinch
Friday, 28 July 2000