Hi Nick:
This is so far OT as to be censurable by Dale, whose indulgence I ask in this case in order to help another cyclist.
Actually, a belt drive is currently being sold by Carbon Drive Systems, a subsidiary of Spot Bicycles.
I understand that the system consists of a polyurethane belt, as well as a special made chainring and cog.
Since, ostensibly, the belt cannot be broken, a keyed dropout must be used. Therefore, such dropouts will be made for both steel and alu bikes.
I imagine more info is available somewhere in cyberspace.
Cordially,
George
George Hollenberg MD
Westport, CT, USA
> At the risk of exceeding my 3 per day limit and not being
> vintage: can anyone tell me, preferably onlist, what attempts
> were made in the past at belt drive on bicycles. More
> importantly, how would the best of today's toothbelt drives
> match a chain drive energy loss wise. Because the ideal
> chainline is a straight one (anyone to contradict me on this one
> ?) , and were a energy-efficient beldrive to be feasible, any
> manually commanded expanding rear wheel pulley wheel (see
> mobylette automatic transmissions for the general idea) would
> give the ideal drive system. An expansion factor of 2.2 on the
> back pulley mech would give a more than large enough ratio choice.
>
> If a belt drive is not a possibility, why has nobody attempted
> a straight chainline variable ratio drive with a different type
> of chain then the standard bicycle chain (the possibilities for
> expanding a back "cog" are innumerable). Or have they. They
> probably have, the amount of left by the wayside innovation in
> early cycles is probably greater than in any other field of
> transportation. To clarify this, I have yet to see an
> "innovation" in modern cycling that was not tested or produced
> at one point or another in cycling history, then dropped for
> reasons of cost or else.
>
> Nick March, Mont de Marsan, Landes, France
>
>
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George Hollenberg MD
CT, USA