gear ratio

Discussion in 'Motorized Bicycle General Discussion' started by lilffihn, Nov 7, 2009.

  1. lilffihn

    lilffihn New Member

    Oct 18, 2009
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    hey there i want to know what the best gear ratio is to go fast...because there isnt many hills where i live so i was just wondering thanks...
  2. 2door

    2door Moderator
    Staff Member

    Sep 15, 2008
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    We'll need a little more information to be able to help you. What engine are you running? 2 stroke, 4 stroke? Bike (wheel) size?
    The 2 stroke in-frame Chinese engines on a 26" bike will give you better top end speed with a smaller sprocket on the rear wheel. A general rule of thumb is to use a 40 to 48 tooth sprocket for most areas where there are gentle slopes to contend with. Top end speed with this sprocket will put you in the 20 to 25 mph range. Going down to a 36 tooth sprocket will reduce your hill climbing abilities but will increase your top in by a couple of mph. You might see 30 to 32 with a good, strong running engine but that depends on other factors like rider weight, tire width and softness, road surface, etc. 35 is pushing it with a stock engine and no modifications. Realistically you'll probably be in the 28 to 30 range. Hope this steers you in the right direction but is based on a 2 stroke engine. If you're using a 4 stroke you'll have to wait for one of those guys to speak up.
    #2 2door, Nov 7, 2009
    Last edited: Nov 7, 2009

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