rear sprocket size?

Discussion in 'Motorized Bicycle General Discussion' started by fauxmaster, Jul 9, 2009.

?

sprocket size makes difference in speed or torque?

Poll closed Jul 14, 2009.
  1. smaller sprocket = higher speed

    75.0%
  2. bigger sprocket = lower speed

    0 vote(s)
    0.0%
  3. smaller sprocket = more torque

    0 vote(s)
    0.0%
  4. bigger sprocket = less torque

    25.0%
Multiple votes are allowed.
  1. fauxmaster

    fauxmaster New Member

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    im building a trike, it is a 3 speed to the rear stock. the cross shaft that has the 3 speed sprocket will only let me clear a 6 inch max sprocket which will be mounted to directly to the shaft and not the bike spokes... does anyone have any ideas as to what will happen with such a small sprocket mounted to the back, will i be traveling faster but slow to get there or slower but a **** of a lot of torque?brnot
     
  2. Cabinfever1977

    Cabinfever1977 New Member

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    you have your poll wrong. you have the torque backwards.
    the correct answer is this:
    smaller sprocket= less torque/slower acceleration/faster top speed
    larger sprocket= more torque/faster acceleration/slower top speed

    6" is around the size of a 36t sprocket i think

    you will be traveling faster but slow when starting out , with less torque.
     
    #2 Cabinfever1977, Jul 9, 2009
    Last edited: Jul 9, 2009
  3. matt167

    matt167 New Member

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    a pic to show your issue would be very helpful.. the bigger the sprocket, the more torque you will have, but a reduced top speed.. smaller will be opposite..
     
  4. Cabinfever1977

    Cabinfever1977 New Member

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    also it would help if we knew what engine you are using.
    if the engine is atleast 1.6hp+ and you can fit a 36t sprocket on there,you should be fine. you might not go up steep hills or take off fast but once you get going, you should be able to fly down the road at some good speeds.
     
  5. matt167

    matt167 New Member

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    got to remember, he has double the rolling force.. 2 rear wheels, full axle and a bit heavier than a bike
     
  6. igore

    igore New Member

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    question
    I have a 3 hp 4stroke engine with a 10 tooth drive sprocket driving a 52 tooth wheel sprocket is that about right???
    thanks
     
  7. Creative Engineering

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    Good grief!!!

    Jim
     
  8. matt167

    matt167 New Member

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    just reread my post... geared tall unless it's got 30" tires.... on a China, it would be a hill climber with a top speed of about 20, but a 3hp 4 stroke has enough torque for the hills, and really 40 tooth would be more than sufficent
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    FO'SHO'!!!
     
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Don't forget the china engine has an internal reduction.
     
  11. igore

    igore New Member

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    this is a harbor freight engine 3600 rpm, this 52 tooth sprocket I found at a garage sale. maybe a tooth change on the clutch sprocket
     
  12. matt167

    matt167 New Member

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    yea, I know, I'm just figuring on what a stock 44 tooth can do, and going from there... as far as the 3hp engine, it'll have about 4 ft/lbs of torque without gear reduction. enough to get up most hills without too much gear
     
  13. matt167

    matt167 New Member

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    that would decrease your torque..
     
  14. igore

    igore New Member

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    on a 26 inch bike I wonder what speed it would go??
     
  15. xlite

    xlite New Member

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    I can tell you the HF 80cc needs at least 80-90 tooth rear and disable governor to get reasonable top speed.
     
  16. igore

    igore New Member

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