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Old 01-27-2010, 06:26 PM
jdcburg jdcburg is offline
Motorized Bicycle Elite Member
Join Date: Jul 2009
Location: massachusetts
Posts: 150
Default Re: RPMs required for various speeds in friction drive

Hi Dan - I've actually finished a bunch of tables. It just took a little while with Excel. I am trying to figure a way to present them in some way that won't take up a lot of space and won't be too hard to find your way through. Maybe I'll put them on a web page and link to it here. In the meantime, if you want to figure a specific bike/sprocket combo you could go to Bicycle Analyzer and put in the numbers to get a top speed for your bike. Just set the wheel size then put the output rpms of your motor in pedaling cadence (usually max rpms divided by 5 for a typical China Girl). Enter the drive sprocket teeth in Front Gear 1 and the rear sprocket teeth in Rear Gear 1 and push Analyze My Bike. If you want to compare a few sizes just enter their values in different Front/Rear boxes. It's probably easier to use the Bicycle Analyzer than anything I could put together anyway - jd
In theory there is no difference between theory and practice. But in practice, there is - Yogi Berra
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