Yep, and they're pretty expensive if you can find one. There have been
other automatic shifters, mostly centrifugal internal hub types and at least
one electric one.
>
>Sounds like a bicycle automatic transmission if I'm understand your
>description.
>
>Charlie
>
>On Tue, Aug 2, 2016 at 9:21 AM, Chris Trask <christrask@xxxxxxxxxxxxx>
>wrote:
>
>> Every so often we have a bicycle show up in our shop that stands out
>> for one reason or another. On Sunday a fellow showed up with an almost
>> pristine 64cm 1980 Motobecane Grand Jubile, the only blemish being the rear
>> wheel, which was not original. He had picked it up for $160 in a
>> non-profit shop in Tucson. I was deep green with envy.
>>
>> But yesterday a bike arrived that towered above anything else I have
>> seen in terms of uniqueness: A CSA Autobike. This ingenious contraption
>> has an automatic rear wheel shifter that operates by way of three weights
>> that slide along the spokes, which operate a trio of clevises, which
>> operate a trio of pistons, and which then push a shifting ring outwards
>> against the chain as the wheel goes faster, shifting the chain to a smaller
>> sprocket. A conventional rear derailleur provides chain tensioning and
>> jockying for down-shifting. The crankset is also a freewheel so that the
>> chain can move while coasting so as to allow the wheel mechanism to shift
>> down as speed decreases. Here are some photos:
>
Chris
When the going gets weird, the weird turn pro
- Hunter S. Thompson
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