Gearing question

[xtman]

Hi im almost done with my BSR! But i decided to go with a simple 3 horse motor since this will be for cruising around car shows and such. I had a question for gearing though... what would you guys suggest i use? Im using a centrificul clutch if that has to do with it... Im just looking for good speed and good torque!

Thanks!

[kkuenemann]

xtman

I used a centrifical on mine also, 12 tooth on it with a 68 tooth on the axle. I am using a 6.5 horse on mine and has plenty of torque for easy wheelie. With the smaller 3.5, I might try 12/72 set up for a 6:1 gear ratio.

[xtman]

Thanks! That helped alot

[xtman]

the guy i got my clutch from told me that HE could only get an 11 tooth sprocket for the motor because the shaft was 5/8th thick. So should i still go with a 72 tooth for the axle? Or should go one gear higher/lower?

[kkuenemann]

If you can only get a 11 tooth clutch, a 6:1 gear ratio, you would need at 66 tooth gear on the axle. A 72 tooth gear would give you a 6.55:1 ratio. The bigger the axle gear the slower you will go, but would be able to get moving from a stand still easier. With at 34" circomferance rear tire (about 12" Diameter), at 3500 rpm with the 11/66 combo you would do about 18 mph.

Hope this helps...:thumb:

[xtman]

Thanks! wow i didnt know one tooth made that much of a difference! So now im learning, because i was still going to get a 72 tooth!