Gear ratio question

Discussion in 'Motorized Bicycle General Discussion' started by sseisup, Jan 16, 2010.

  1. sseisup

    sseisup New Member

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    I built a 26" bike with a 44 tooth sprocket and a 60cc motor. I rode it side by side with my motorcycle and it did 40mph but was reving what I thought was insanely high. Now I'm building a bike with 20" tire and wondered how small a sprocket I should go with to match or better the the ride. Not to go faster but to get the rpms down. This would be harder on the clutch but better on the motor right? Now that I'm on the subject, the clutches are replaceable right? Thanks guys!
     
  2. BarelyAWake

    BarelyAWake New Member

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    As I never had a bike w/20" wheels I can't give you specifics and TBH much depends on environmental variables such as engine power output (modded/stock), bike, cargo, and rider weight, terrain, and ofc wheel size as you've said. While you can always compromise acceleration for top speed or vice-versa - the problem remains that you're compromising. Finding that "sweet spot" between the two tends to take a LOT of experimentation due to the variables above.

    While no doubt someone more knowledgeable than I can give you a good recommendation for which sprocket will getcha in the ballpark - I really recommend considering a shiftkit if ya wanna get the most outa yer bike.

    Still, just a sprocket swap is pretty easy (partic if you have a sprocket adapter) and I wouldn't worry too much about the clutch. Not only are the pads replaceable but you'll find that you'll just pedal a bit more to start off, not such a bad thing to hafta do ;)
     
  3. sseisup

    sseisup New Member

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    I have a single speed coaster brake, so no need for a shift kit. Sprocket adapter is neat, but I'm mostly trying to figure out the ratio so I can gear it up a little, and pedaling on take off is no big deal. I did some math and it looks like a 33 or so should do the job if I'm right. Am I right?
     
    #3 sseisup, Jan 16, 2010
    Last edited: Jan 16, 2010

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