Will HD Axle kit work with 7 speed firmstrong?

Discussion in 'Frame Mounted Engines' started by brian h, Oct 18, 2009.

  1. brian h

    brian h New Member

    I am thinking of building my next bike, I would like to get some advice. I want to buy a Firmstrong CA-520 with 7 speeds. I do not want a rag joint sprocket. Cant the HD Axle kit from Bicycle-Engine.com be used with a 7 speed?

    I would be interested in hearing your oppinions on other options to mount the drive side sprocket. Does anyone know if the rear hub on the CA-520 is cylindrical or elliptical? I was thinking about buying the sprocket mount from Manic Mechanic as an alternative.

  2. ocscully

    ocscully Member

    The HD Hubs when you buy them are spaced for a single speed freewheel. They can be setup for a multi speed freewheel fairly easily by flipping the axle and adding some spacers to the right side. AlaskaVan did this on his tadpole trike build and posted a pretty detailed discription of this change with photos here on the forum. What motor are you going to use? If you are using HT 2-stroke?, you need to be sure that you get the Type II HD Hub (the non freewheeling one)

  3. brian h

    brian h New Member

    I want to use a four stroke but I have a two stroke on hand. Why would the freewheel screw me up?
  4. wildemere

    wildemere Member

    Another option is a disk brake rear hub. The disk mount will handle the drive sprocket with the correct hardware.

    The 2 stroke needs a solid mount for starting, (unless you have a pull start ) the 4 strokes are pull start and use a freewheel on the drive side.
  5. ocscully

    ocscully Member


    a freewheeling motor driven rear sprocket will not allow you to bump start the 2-stroke motor. You need a fixed sprocket to bump start the motor. For a 4-stroke with a pull/rope starter the freewheeling rear sprocket allows you to pedal the bike with alot less resistance.