Gear ratios for HF bike -- please help!

FFV8 said:
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.

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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
 
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11/60 works. That gives a 15.27 overall, which will climb hills better

Puts your 5k cruise at 25 mph - which is a good speed on a bike.

What sort of brakes are you planning?
 
FFV8 said:
11/60 works. That gives a 15.27 overall, which will climb hills better

Puts your 5k cruise at 25 mph - which is a good speed on a bike.

What sort of brakes are you planning?
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Great. I think once I get the build underway, I'll start a new thread with pics. As for brakes, uh.......... I have a set of regular side pull calipers that brought me to a stop at 34.4 mph on my previous friction drive build. However, I was given a running, commercially built mini dirt bike yesterday, which has key start, headlights, windshield, big gas tank, and full front and hub mounted disc brakes, among other goodies. So I am goin' to decide if I want to use parts from that to make this bike really awesome (electric start, etc.) or if I want to keep the two separate. Decisions, decisions. What do you suggest?

.bf.
 
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