chain distance from center?

Discussion in 'Frame Mounted Engines' started by jaguar, Nov 30, 2010.

  1. jaguar

    jaguar Well-Known Member

    I am going to have a 48cc Chinese engine put on my 21 speed 26" mountain bike but I need to know what the distance is from the center of the bike frame to the near side of the chain. Hopefully it is at least 1+1/16" because that is the distance from center to the outer edge of my 2+1/8" wide tires. And please don't tell me to get smaller tires because where I live the rear tire needs to be fat to absorb much of the street bumps. Rear has no suspension. Half the streets here in Ecuador are made of stones like some places in Europe.
    second question:
    I'd like to have a better rear sprocket setup than bolting to the spokes and I was thinking of directly mounting a sprocket ( to a hub made for a brake disk. They sell sprockets with 3 different center offsets. If anyone has experience with these then which offset should I request?
    thanks all!

  2. 5-7HEAVEN

    5-7HEAVEN Guest

    Hard to answer this. Each bike has different dimensions, especially if you are creating left-hand chain drive.

    What bicycle do you have?

    Methinks you would have to mount your engine first. Then use a long straight-edge or string, from engine sprocket to rear wheel hub.:detective:
  3. jaguar

    jaguar Well-Known Member

    I know the second question is hard to answer but not the first.
    Please someone just measure from frame centerline to chain.
  4. jaguar

    jaguar Well-Known Member

    I went to a shop and measured one today. 1+1/4" frame centerline to near side of chain.
  5. loquin

    loquin Active Member