What size sprocket for me?

Discussion in 'Motorized Bicycle General Discussion' started by craigant, Oct 24, 2008.

  1. craigant

    craigant New Member

    Joined:
    Aug 6, 2008
    Messages:
    10
    Likes Received:
    0
    ok I thave my kit all done but I would like to go a bit faster without reving the crap out my my engine. I have a 80cc engine with a 44 tooth sprocket right now. I am going to order a kings sprocket but before I spend all my money and get one sent all the way from the states I would like to ask which size would best suit me. I am a big boy 124kg (272lbs) I have broken my engine in and it runs like a dream. the power band seems to be from 24 to 30 kmph (15 to 18 mph) and my engine will only pull me up to 40kmph (25mph) I am quite happey at 25mph however I would like that speed while the engine is in the power band as the engine runs sweet in that rpm range. so what size sprocket should i order to be able to site on around 40kmph or 25mph without reving the crap out of the enigine??
     
  2. old motorbike

    old motorbike New Member

    Joined:
    Sep 21, 2008
    Messages:
    352
    Likes Received:
    0
    I was going to get a 36 tooth, but before that, I opted for a SBP shift kit and that slowed the engine down a lot.
     
  3. OSCAR383

    OSCAR383 New Member

    Joined:
    Jul 22, 2008
    Messages:
    243
    Likes Received:
    0
    WHAT SIZE RIM ARE YOU RUNNING IF YOUR ON A 26" RIM YOU SHOULD BE GOIND ALOT FASTER THAN 25. TRY SCREWING THE METAL SLEVE ON THE THROTTLE CABLE OUT SOME (AWAY FROM THE THROTTLE ASSEMBLY) SEE IF ITS GET YOU SOME MORE TOP END.
     
  4. craigant

    craigant New Member

    Joined:
    Aug 6, 2008
    Messages:
    10
    Likes Received:
    0
    I will do that and see if it makes a difference. I have 26inch rims but remember I am 125kgs
     
  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    4
    That's about right for a guy your size. When I weighed 200# I GPS'ed the bike @ 28 mph max. Some are faster than others.

    Total weight and wind resistance have a lot to do with top speed, going to a higher gear will likely not net you much of a top end gain as much as it will lower your RPM @ cruise.
     
  6. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    4
    Tire/wheel balance and size have a little to do with it too. Knobbies? Drops about 2-3 mph. Fat 2.25's with 35 psi? Drop another few.
    Out of balance wheels? 1-3.
     
  7. craigant

    craigant New Member

    Joined:
    Aug 6, 2008
    Messages:
    10
    Likes Received:
    0
    cool thanks for that bikeguy joe, I now now its normal speed for my size. I think I will stick with the 44 tooth sprocket but lose my knobbies.
    Cheers
     
  8. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

    Joined:
    Jan 8, 2008
    Messages:
    11,529
    Likes Received:
    4
    I "lost the knobbies" on the street and gained some mph.

    Once you get some miles on it, you will see a small improvement as well.
     
    #8 Bikeguy Joe, Oct 26, 2008
    Last edited: Oct 26, 2008

Share This Page