Installation on a 3-speed?

Discussion in 'General Questions' started by kjmillig, Feb 14, 2008.

  1. kjmillig

    kjmillig New Member

    Does anyone have experience installing a gas engine rear gear on a 3-speed internal-geared hub. I'm thinking of putting a 70cc engine on one.

  2. grndslm

    grndslm Guest

    I'd be interested in this as well. I'm thinking about getting an 8spd internal-geared hub on a Downtube foldable 20" bike, and options seem to be so readily available for this specific bike.

    Let's see... I could hook the chain directly up to the freewheel in the back and have gears, but of course, I'd have to let off the gas to change gears, but this will prolly give me greater gas milage AND too much speed for a foldable frame. I could leave the chain on the pedals in tact and put spokes thru the engine's sprocket. Or I could get an electric hub with a huge battery, prolly making it still truly foldable. ??? I dunno yet.
  3. azbill

    azbill Active Member

    it has been proven that the internal geared hub will not take the power of these engines
    you can still use the gears for pedalling, just not for engine
    but, you can still mount the drive sprocket on left side (I believe you will need to make the sprockets center hole larger to accomodate the hubs larger diameter)
    a quick search of 'internal gears' shows these threads dealing with this
  4. grndslm

    grndslm Guest

    According to one of those two threads you gave me, it sounds like someone has already been using the internal gearing on the NuVinci hub for quite some time now.

    I read somewhere else, something about Torsion Bars or something that made it more stable....

    I hope my Sturmey Archer 8spd hubs can handle some motor tugging.
  5. azbill

    azbill Active Member

    the nuvinci is expensive ($300) and made for an engine (staton sells them)
    I was giving examples of the search
    your money, spend it this way if you want
    you really need to do some research tho
  6. grndslm

    grndslm Guest

    I did the research, your search terms came up with better searches, tho. Either way... none of the threads were definitive about whether or not hubs with internal gears would work. Only the one that I linked to above had any hope, and sure enough... the guy posted pics when I asked, and it appears that he's been riding it for a long while.

    I highly doubt I would hook the engine's chain directly up to my Sturmey Archer 8spd hub... but whenever I get a real bike, you'd better believe I'm gonna set it up almost exactly like this:

    Soo... Is the NuVinci really the only one made for motors?? It's the only brand I've heard of more than once on this forum.
  7. Internal gears

    I have been using a Nexus 7 speed for about a year & a half on this bike.




    I have heard the nightmares about stripping gears & so I release all motor power before I shift it. So far no problems.
  8. grndslm

    grndslm Guest

    I would have assumed that as long as you change gears the way the hub was designed to change gears... it's prolly gonna work.

    Now that I've got living proof that it works... it's off to dream of the perfect frame.