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See this wheel. Can I put two freewheel cogs on it, instead of one freewheel and one fixed? (driving clock and anti clock, so both driving forward) Then get this wheel onto front steel fork, by bending open a bit? I haven't fully worked out the driving thing yet, so can't explain it. Thanks enter image description here

  • Do you have a local bike shop with a mechanic who is not afraid to try things? – Willeke May 6 '18 at 11:32
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    A normal flip-flop track hub and a widened fork set from 100mm standard to 120mm rear track standard or maybe better custom built because you'll need attaching points for the required connecting gears. – Carel May 6 '18 at 14:39
  • I've seen a few designs online for two wheel drive bikes. It's not clear why you'd need freewheels on both sides. – Chris H May 6 '18 at 15:57
  • A single cog could be done easily by using a disc brake hub with a cog desgined to mount to the 6 bolt disc mount. Would be fixed though. – ankh-morpork May 6 '18 at 16:51
  • There are a few front forks designed for rear spacings (e.g. for fatbike touring use a long way from civilisation) but they're probably expensive – Chris H May 6 '18 at 21:01
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If you really need a freewheel on each side, that both drive the wheel forward, then you would need a custom built hub with a left hand freewheel thread on the left hand side, and you'd need to build a left hand freewheel too.

If you just needed a freewheel on the right hand side, just use a single speed bike rear hub.

You would of course need a custom fork for either as rear hubs are wider that front hubs.

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    You could probably buy a "flip-flop" wheel and figure some way to lock the "wrong" side threads (along with the freewheel). – Daniel R Hicks May 6 '18 at 12:15
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Focusing on the fork part of the question:

Remember the front wheel is an OLD of 100mm (just under 4") so you will need to spread the legs/tines of the fork to give room for your changes.

This means you will need a steel fork. No other material can be spread, and even a steel one might break.

Consider that spreading the fork will un-align the front dropouts. They will need to be bent back to vertical too.

You also require a rigid fork because this level of bending will render any suspension ineffective.

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    Fwiw, he could also get a surly pugsley or similar fork, which has 135mm spacing. – whatsisname May 7 '18 at 3:34
  • @whatsisname you're right - Also, on a tandem the fork is spaced the same as the rear wheel (for proper tandems anyway.) – Criggie May 7 '18 at 6:29
  • Thanks, so if I spread a steel fork apart an inch or two, will the spring back tension cause a problem with the hub or cogs? – Mike Flanagan May 7 '18 at 10:12
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    @MikeFlanagan: you would have to spread the fork more than the target, such that when the stress is removed it returns to the target. en.wikipedia.org/wiki/Yield_(engineering) – whatsisname May 7 '18 at 15:42
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Some of the early velocipedes were front wheel drive:

front wheel velocipede

And many folks have created experimental front wheel drive bikes and recumbents:

goog image search

The problem as @criggie notes is that the dropouts are not the same size front and rear.

There’s another problem which front hub drive ebikes experience which is that the front wheel loses traction very easily when accelerating or going uphill. So you lose all your power just when you need it most.

  • My idea is a modern take on that Gompertz job, thanks for your answer. – Mike Flanagan May 7 '18 at 10:14

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