3 speed freewheel hub

Discussion in 'Motorized Tandems, Trikes and Recumbent Bicycles' started by mkatt4x4, Jan 19, 2014.

  1. mkatt4x4

    mkatt4x4 New Member

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    On my way home tonight I was thinking of a sweet setup I might try; on the idea of a 3+ speed hub in between the motor and the wheel sprocket on the left side. I knew before hand of internal geared hugs, but visualized a problem installing a 2nd gear onto the hub.

    I was thinking of this in my mind, exactly as pictured
    [​IMG]
    but with the freewheel option instead of the coaster brake. That was the first picture that came up when I googled it. It comes from http://www.industrialbicycles.com/hub_options.htm So I think the left it comes from the crank, on the right it goes to the wheels.

    So its a common enough product. Now where does a guy buy this. It will be some fabriction, but if the price is right, should beat a jackshaft.
     
    #1 mkatt4x4, Jan 19, 2014
    Last edited: Jan 19, 2014
  2. mkatt4x4

    mkatt4x4 New Member

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    I found it its a Sturmey-Archer "Gearbox" something like a SRC3
    [​IMG]

    called an adult tricycle hub
     
    #2 mkatt4x4, Jan 19, 2014
    Last edited: Jan 19, 2014
  3. silverbear

    silverbear The Boy Who Never Grew Up

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    Is anyone familiar with this? I don't see how it would be set up.
    SB
     
  4. mkatt4x4

    mkatt4x4 New Member

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    I would assume the motor would have to be slightly off to one side for the chain to line up properly to the rear wheel sprocket. It can be done within the frame, how far of an offset depends on the distance between the 2 sprockets on the hub. The challenge is if theres too much of an offset, how will it affect pedalling the bicycle. It could also be a rear rack mount setup. I just dont know how much torque these hubs can take. There is a thread on the endless sphere website that I stumbled upon about the hubs strengths and yes people have done a similar setup for electric, I think it would be totally cool if the price is right or if I can find a used 3 speed and a 8 or 9 speed in combination, the options are limitless. I am going to have to hang out at the local community co-op bike shop now and scoop me up some hubs.
     
    #4 mkatt4x4, Jan 27, 2014
    Last edited: Jan 27, 2014
  5. curtisfox

    curtisfox Well-Known Member

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    If you look close you see the inside sprocket is bolted to the spoke flange that normally turns the wheel. If you took a normal hub and turned it arould like this you would be just applying the brake, so these hubs must have the inturnals reversed or something to that efect to work that way...........Curt
     
  6. professor

    professor New Member

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    That is a great design.
    When I did my SA as a jackshaft, I didn't think of such an arrangement.
    It still need another jackshaft to get the motor output transfered to the other side before going to the SA.
    These hubs work fine as an intermediate member of the drivetrain because the torque is only multiplied a few times.
    My 212 puts out around 10 ft lbs and the little hub does fine.
    Gotta keep oil in them though.
    Inside a rear wheel it would likely strip out with the greater tq. multiplication.
     
  7. KCvale

    KCvale Well-Known Member

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    This system looks to be for a rear mounted engine that is way off to the side (part the bottom of this pic) for the spin of the engine output to turn the wheel the right way.

    [​IMG]

    From that pic perspective; that outer sprocket has to spin clockwise to move the bike forward.

    This 3-speed system as well as a 6 or 7 speed derailleur version are on all kinds of trikes and I love them, especially with a center mount electric trike, but they are all on the right pedal side.

    To make all of this this easier to understand, just that the chain on the top of any chain sprocket needs to spin in the direction of forward travel.

    There are no bicycle drive systems or gas engines I know of that are designed for the bottom of the sprocket to spin in the direction of travel.

    Just think about that.

    Chains PULL in the direction of travel on the top side of a loop for what is available for our needs because that is how the bicycles themselves are designed from the frame up, and that drive 'input' is always on the right side for pedal stuff.

    In short if you want to use a left side independent drive system you can but it still involves a jackshaft of some sort to transfer the power in the proper direction with gears in between.
     
    #7 KCvale, Jan 27, 2014
    Last edited: Jan 27, 2014
  8. Pelican Pete

    Pelican Pete Member

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    It looks like the pic shows the underside, so I think the Front arrow should point to the left.
     
  9. d_gizzle

    d_gizzle Active Member

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    Round of applause for Pete!
     
  10. KCvale

    KCvale Well-Known Member

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    Look again at the coaster brake orientation and opening in the mount.
    If this is a mid mount drive then the drive chain is the pedal side which works dandy.
    The proposal was to flip it over for left hand drive.

    ALL coaster brakes are opposite the drive side, you can't reverse the drive side direction and have it work which is what this topic was about before that part was apparently deleted.

    Simple fact, you can't just flip anything over to work from the other side.
     
    #10 KCvale, Feb 24, 2014
    Last edited: Feb 24, 2014
  11. maniac57

    maniac57 Old, Fat, and still faster than you

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    Yeah. If it were that easy, everyone would be riding 8-speed shifter builds.
     

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