Discussion in 'Frame Mounted Engines' started by Unregistered, Feb 18, 2008.

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  1. Unregistered

    Unregistered Guest

    I am planning on building a motorized bike (49cc), and i have read some stuff about using a 44 toothed sprocket for speed instead of a 52 toothed sprocket. I want it to go fast, but i was just wondering what the benifits and drawbacks were for each, or if there was another size that is better. Thanks for the help.

  2. mickey

    mickey Guest

    I've used a 44 and a 50 tooth sprocket on a Kings "80". The 44 works fine for the little hills along the coast here and still exceed 27 mph. The 50 tooth could pull small wheelies :grin:
  3. HoughMade

    HoughMade Guest

    Generally, if you go with a smaller sprocket, to apoint you get higher top speed, but it hurts acceleration. A smaller sprocket will reduce top speed, but improve acceleration.

    2 stroke or 4?
  4. fetor56

    fetor56 Guest

    A smaller rear sprocket also reduces torque(the ability to pull)
  5. FWIW - a 44T is still a little low gearing for many......of course optimal gearing depends on many factors such as riders weight, terrain, altitude above sea level, etc...

  6. Andrew735

    Andrew735 Member

    I started this thread and decided to register.

    I decided to stop being lazy and just register. I want to put a 4 stroke 49cc motor on a beach cruiser. Thanks for all of the help. I want a sprocket that has top speed, but some get-up and go. Is there a sprocket that will give me that? The kit Im looking at buying comes with a 52 toothed sprocket by the way.
  7. loquin

    loquin Active Member

    There IS no 'magic bullet' when it comes to sprocket size in a single gear ration system. It is a compromise between acceleration and top speed. The factors that come into play are the riders weight and the terrain, as well as what is more important to the rider.

    As others have said, the smaller the rear sprocket, the higher the top-end speed. However, the smaller the rear sprocket, the lower the torque applied to the rear wheel, (and thus the lower the acceleration.) If the terrain is flat, and you're a low-mass rider, then the 44 tooth sprocket will give you a high top end with acceptable acceleration. If you're like me (a rider whose scales groan at sight of him- I was a defensive tackle in college, after all) or who will be riding in the hills a lot, you might want to go with the larger sprocket.
  8. Andrew735

    Andrew735 Member

    thanks for the help loquin. i think i will go with the 44 th.