Build a wheel hub with freewheel gears on both sides?

Discussion in 'Spare Parts, Tools & Product Developement' started by skyl4rk, Jun 13, 2008.

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  1. skyl4rk

    skyl4rk Guest

    Bicycle mechanics please help:

    Is it possible to build a wheel hub with freewheel gears/sprockets on both sides using readily available parts?

    Ideally the gears would be 44t on the left and 15t on the right, and both would freewheel when coasting.

    I have heard of a hub called a fixed gear flip flop hub, which has a freewheel on one side and a fixed gear on the other. Maybe one of these hubs could be built with a freewheel gear on each side, both freewheeling in the same direction?

  2. ocscully

    ocscully Member

    Unfortunately the flip flop type of hub will not work since both sets of threads are right hand threads. To accomplish what you are asking you need a hub with left hand threads on the left side. Staton-Inc makes such a hub as does GRUBEE Then the problem becomes getting the 44t you want for the left side. The left hand thread SS freewheel that Staton offers is an 18t. You might be able to custom mount the 44t to the 18t freewheel. The Grubee Hub comes with a lefthand threaded freewheel with a universal mounting flange rather than a sprocket and you mount what ever sprocket you want to it.

  3. MacTac

    MacTac New Member

  4. lennyharp

    lennyharp Member

    David Staton offers a special hub with a special freewheel as part of his motor gearbox assembly. You get some well machined and designed parts from David. I am thinking of getting my second kit from him. He does sell just the parts so you can go that way if you already have most of what you need.
  5. yeah it will work if you flip flop your engines drive shaft direction to the desired freewheel movement to get forward rotation flip flop the engine this will be easiest on a rear carrier setup
  6. Nuttsy

    Nuttsy Member

    Something in the water?

  7. happycheapskate

    happycheapskate Active Member

    If the 44t/xx size cog on the left freewheels, you will need a pull start and locking clutch lever or centrifugal clutch on your engine. You will not be able to pedal start it.

    I believe this product is what you are looking for.
    Consult the seller before buying. I believe it has a left side 36t freewheel, and takes a standard BMX freewheel cog on the right. I could be wrong though, so contact the seller.
    Last edited: Dec 30, 2009
  8. happycheapskate

    happycheapskate Active Member

    Thanks for the idea. I will use this product in the next MB build if use pull start

    Good question though: I would like to use this product if I built a bike with a rope start. Then I could pedal the bicycle normally with the engine off.
    Keep in mind you can thread a 6speed freewheel onto a bmx hub, but you might have to expand your frame to fit and still clear the 36t left cog and chain to avoid sawing off your chainstay.
    A nice alternative would be to simply use a BMX freewheel in the back and a 22/32/42 front chainring, with the rear derailleur on only to take up slack. (use a bicycle spoke or coat hanger to make a "cable" substitute, to hold the derailleur in place on the only rear gear.) 3 speeds ought to be enough if you have a motor. I've used a 3 speed bicycle like that before (It had a 28/38/48 c201 crankset) . It was a nice townie bike. I'm currently using a MB with a one speed pedal side, and its enough to start bike and take off from stop lights under human power, or ride up to the office buildings.

    PS they are "rare" but there are 2 speed RH thread bmx freewheels,
    And you may be able to find an ACS or similar for much much less.
    Last edited: Dec 30, 2009
  9. loquin

    loquin Active Member

  10. happycheapskate

    happycheapskate Active Member

    That is nice, but what LH threaded freewheel is 36t or bigger?
  11. Alaskavan

    Alaskavan Guest

    Last edited by a moderator: Jan 3, 2010
  12. ibdennyak

    ibdennyak Guest

  13. StreetPlanes

    StreetPlanes Guest

    Staton Inc has the very item you're looking for in stock. I've bought and built several using their dual freewheel hubs. Not cheap but good products.
  14. Alaskavan

    Alaskavan Guest

    Hi Denny. I have burned up one set of bearings. Keep in mind that I often ride 30+ miles at a stretch at 40mph+. I switched the bad bearings for the set in the spare hub I bought. I also bought a set of SKF bearings for the next time I need to replace them.
  15. happycheapskate

    happycheapskate Active Member

    Does using a dual freewheel hub with the 36 or 44 motor cog, allow for very consistent chain tension? I would think this should be a major improvement over the rag joint, esp if using no tensioner.

    I put half links in my chain recently and didn't quite put enough chain tension on, and the chain skipped off this morning. I am glad I installed a few washers on the left side of the axle, which gave the chain a place to fall instead of tangling with the spokes or cog. I rode it 30 miles today and all is well, so I guess I have to just run the chain as reasonably tight as possible considering the run out of the cog rotation.
  16. ElementX

    ElementX New Member

    Alaskavan, did you have any issues threading that 7 speed onto the hub?

    I just received this hub and it doesn't appear that any of my multi-speed freewheels will screw onto the right drive side. They thread-on maybe 2 turns, then wont go any further by hand.
  17. happycheapskate

    happycheapskate Active Member

    Element X. Most freewheels sold in USA have the same thread, but there are a few different threadings. Its possible you have an incompatible thread, but more likely that the threads are dirty on one of the items, or that the threads are cut poorly on the hub. Check with a bike shop, but I bet you can grease it and put it on there. (it won't seize/corrode and will be easier to remove some day when you need to work on your hub/re lace the wheel)
  18. Goat Herder

    Goat Herder Member

    Fine threads being the case get some brake clean and an old tooth brush. Clean it good. Just a tiny bit of buggering on those fine treads can ruin your day! Do grease it up good! A bike shop might be a good Idea!

    I have buggered fine threads as a mechanic its a night mare..
  19. ElementX

    ElementX New Member

    Thanks for the responses guys. I will give it another try with your suggestions.

    At the moment, I am thinking that the threads on the hub are possibly too deep (or is it that they're too tall?) because I've tried 4 different freewheels on it. 1 was brand new, and all 4 fit fine on other hubs.
  20. loquin

    loquin Active Member

    You sure it's a left-hand thread?