dvt wrote:
>>> Any idea how I could fabricate a dual hub?
>> Buy one. Anything fixed/free or fixed/fixed will do you right, since a
>> single speed freewheel will screw onto the threads for the track cog if
>> you want. It won't be cheap, though, especially considering the cost of
>> two single speed freewheels. But it will be cheaper and work better than
>> screwing around trying to fabricate something from existing cassette
>> hubs.
> But the freewheel on the left will spin backwards... unless you get a
> left-side drive (LSD) freewheel.
>
> Get a flip-flop hub, one normal freewheel, and one left side drive
> freewheel. Bob's your uncle.
>
I saw a wheel like this last week, used in a bicycle with a stepper
mechanism instead of rotary cranks. The (longer than normal) cranks were
attached to levers, that had chains attached to them. The point of
attachment of the chain to the lever set the gearing of the bicycle.
When the crank was depressed, the lever pulled the chain, which pulled
the hub. Also a run of chain around the seat-tube at the bb caused the
other pedal to rise when the first was depressed.
Both cranks were connected to the hub this way, on opposite sides, to
two freewheels arranged as you describe. Stepping with the right foot
drove the right sprocket, and stepping with the left the left. The bike
was in the LBS for repairs to the unusual drive train, and the mechanics
were getting creative. I think it was being ridden by someone with a
disability that made stepping easier than pedaling. Sure was a weird
bike to ride!
