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Old 12-05-2008, 09:43 PM
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conradcliff conradcliff is offline
Motorized Bicycle Senior Member
Join Date: Oct 2008
Location: Tampa, Fla.
Posts: 67
Default Re: Need mental and ratio help! Please!

Originally Posted by 5-7HEAVEN View Post
Change the engine sprocket to 6t and the first input jackshaft sprocket to 24t. You'll arrive at a negligible fraction off of the first calculator.

You will arrive at 6.87:1 on first calculator and 6.85 on second calculator, which is WAYYY too high of a gear for 6,000rpm/7,000rpm engine range.

The last sprocket combo from crankset to rear drive sprocket is NOT a gear reduction.

For 40mph at 6,000rpm, gear ratio should be 11.6:1.

For 40mph at 7,000rpm, gear ratio should be 13.55:1.

more info later.
How do the new numbers look to you?

Originally Posted by Saddletramp1200 View Post
I am most likely wrong, but I may see what is getting at. I have seen a sprocket with 25 teeth that was 4 inches IN DIA. I have seen a sprocket with 25 teeth 4 FEET tall. Is this what your saying?
Yeah, that was pretty much my reasoning process..but as it turns out it was a flawed one..
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