Optimum off-road-motor bike gear ratio?

Discussion in 'Motorized Bicycle General Discussion' started by dtj6ppc, Feb 23, 2011.

  1. dtj6ppc

    dtj6ppc New Member

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    Is there a gear ratio calculator or formula that can determine the optimal final low drive gear ratio for an off-the-road motor bike?, that will take into consideration;

    -a total bike, motor, rider, and carry weight of 325 lbs

    -1.6 horsepower

    -7,000 max rpm

    -40 percent max incline grade climb capability

    -26 inch wheel diameter

    -at 5mph

    thanks..................Don
     
    #1 dtj6ppc, Feb 23, 2011
    Last edited: Feb 23, 2011
  2. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Hey there Don Redondo, welcome to the forum! It would help knowing what kind of gearbox you are running to determine what you're looking for gear ratio wise. Or are you trying to determine which type of gear box to use?

    Please let us know....help is on the way! dnut

    Side note......if you're running a 4-stroke engine, a 72 tooth rear sprocket comes too mind.

     
    #2 scotto-, Feb 23, 2011
    Last edited: Feb 23, 2011
  3. dtj6ppc

    dtj6ppc New Member

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    Hi Scotto,

    Exactly, I am trying to figure out what combination of gear box, jack shaft gears, crank gear, and rear wheel gear that combined will give me a final drive ratio adequate enough to move 325 lbs up a maximum incline of 40 percent, using 1.6 horsepower, at 7,000 rpm, at say a minimum speed of 5 mph........................Don
     
  4. dmb

    dmb Active Member

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    climbing back up the cliffs with the surfboard at p.v.?
     
  5. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Even with a 2-stroke HT, I think that 72T rear sprocket would do the trick! ;)
     
  6. dtj6ppc

    dtj6ppc New Member

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    Re: Optimum off-road-motor bike gear ratio?

    That and the lobsters from the traps at Christmas Tree Cove.........you know me too well...............Don
     
  7. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Well then I'd say a rear sprocket of 72-75 teeth on whatever set-up you decide on. I don't recall the cliffs at Palos Verde being much different than that of Blacks down here.....hope you're gonna use a rear rack mount for your board, unless you don't mind dings? Cheers!
     
  8. dmb

    dmb Active Member

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    maybe an auto clutch if their any good, a stall on a steep hill could be a tough re-start
     
  9. dmb

    dmb Active Member

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    err i mean tuff
     

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