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Old 03-13-2012, 11:53 PM
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a_dam a_dam is offline
Motorized Bicycle Elite Member
Join Date: Feb 2009
Location: Momence, IL
Posts: 349
Default Re: ON MY FIRST BUILD From Pearland , Tx

a_dam ,
yes i want in frame and ill make it work
That's the spirit. If you know what you want, you gotta go for it. I'm not trying to talk you out of frame mount. Mounting a motor in a frame isn't a huge deal. It mounts in the frame of a pocket bike, after all.

i will have a 11 tooth up front and a 72 in the rear
Does that motor have built-in reduction? The "China girl" bike kit motors have a gearbox, so the motor sprocket (10 tooth?) spins at 1/4 the motor rpms. Most people use a rear wheel sprocket of about 40 tooth. So the final ratio is about 16:1. I think you need a pretty strong motor to get away with 16:1; for max torque, people shoot closer to 20:1.
There's no way around that. An 11t front/ 72t rear will give you 6 1/2, you'll need to multiply that by about 2 1/2. If that motor has some kind of trans, then you can have a chain from motor to rear wheel.
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