Can I use a 3speed hub with a Chinese 44 tooth stprocket?

Discussion in 'Frame Mounted Engines' started by Namtraf, May 4, 2007.

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  1. Namtraf

    Namtraf Guest

    I'm building the bicycle right now to put the motor in. I have a pretty sweet 3speed hub that just rebuilt not to long ago. I thought it would be neat to use with the engine kit because I have a Bendix sitck shifter to go with it. I just don't know if I should set the bike up with the 3speed set up because the hub is about three inches round and I don't know if the 44 tooth sproket will be able to mount on there. I haven't got my engine yet but I wanted to get the bicycle done before I get it.

  2. gone_fishin

    gone_fishin Guest

    the sprocket won't fit outta the box, but it can be modified to fit, getting it centered and true is the issue.

    the hub is only gonna be a 3-speed during pedaling, so long as it can handle the added stress/speed it'll be fine. make absolutely certain you've preventive-maintainence'd the thing to the max...good high-temp lube & plenty of it.

    other guys who have multi-speed hubs will be able to help more...stay tuned.
  3. nms

    nms Guest

    I have NO personal experience, but I have heard on other threads on here that a 3 speed hub will quickly be destroyed if used with an engine, even if you don't shift. An 80 cc puts out a lot more power than that hub is designed to deal with (a human might put out a peak of .75 to 1 hp max, while that 80 cc engine you've got will put out a continuous 2.5-3 hp!)
  4. srdavo

    srdavo Active Member

    no experience here, either, but.....on a basic install, the 44 tooth motored sprocket shouldn't stress the innards of a 3 speed hub. i believe the hub problems were encountered when the engine power was routed to the pedal side for shifting purposes. Can anyone post a link to the 3 speed threads?
    The center hole of the sprocket will prolly need to be made a lot bigger. I've enlarged a few of them with a dremel, but only about 1/8" larger. If I had to ream one out much bigger, I'd find a machinest.
  5. psuggmog

    psuggmog Guest