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Old 08-13-2014, 01:24 PM
cschade cschade is offline
Motorized Bicycle Senior Member
Join Date: Aug 2014
Location: United States
Posts: 50
Default Re: Gear ratios for HF bike -- please help!

Originally Posted by FFV8 View Post
Sprocket choices depend on how much fabrication skill you have, and what soer of equipment you have to use.

You should do most of your reduction i the first stage. You are planning on using the bottom bracket bearings for a jackshaft, and they are not high speed items. I would really recommend replacing them with sealed ball bearings.

The 28T final sprocket limits you to a few choices, none of them easy bolt up stuff.

12/65 > 10/28 just makes it. A 65T #35 chain sprocket would have to be fitted to the jackshaft input, and a 10T sprocket on the output.

12/72 > 12/28 works too, but the 72T #35 sprocket is over 9" OD with a chain wrapped around it.

FFV8 -- thank you!! Do you think I'll be all right if I have 11/60 > 10/28 ?? Thank you again for all your help

EDIT: the pedal cranks on the bike I'm using are sealed bearings

Last edited by cschade; 08-13-2014 at 01:25 PM. Reason: I can
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