Gear ratios for HF bike -- please help!

GoldenMotor.com

cschade

Member
Aug 8, 2014
51
0
6
United States
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:

FFV8

New Member
Oct 29, 2013
551
16
0
Spring Valley NV
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?
 

cschade

Member
Aug 8, 2014
51
0
6
United States
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?
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.