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From: eirik@tekchips.UUCP (Eirik Fuller)
Newsgroups: net.bicycle
Subject: Re: elliptical phrases
Message-ID: <296@tekchips.UUCP>
Date: Wed, 16-Oct-85 03:32:55 EDT
Article-I.D.: tekchips.296
Posted: Wed Oct 16 03:32:55 1985
Date-Received: Fri, 18-Oct-85 00:49:52 EDT
References: <1836@kestrel.ARPA>
Reply-To: eirik@tekchips.UUCP (Eirik Fuller)
Organization: Tektronix, Beaverton OR
Lines: 27

In article <1836@kestrel.ARPA> king@kestrel.ARPA writes:
>
>Can anyone comment on elliptical chainwheels?
>
>I wonder about deurailler wear with one of those, since I understand
>your mechanism would flex twice every revolution.
>
>-dick


I have never held one in my hand, but I've seen one up close, in
action. Surprisingly, the derailleur pulleys move only during
shifts. (I never did get around to formulating a mathematical proof
of this, but I've seen it happen).

Needless to say, a front derailleur is out of the question, though
the same is not true of Biopace chainwheels, the 'other' odd-shaped
chainwheels.

By the way, I have wanted an elliptical chainwheel for some time. Is
there anybody out there who knows where I can get one to fit a TA
bolt circle (five holes, very close together)? I want one for my
Hypercycle, which has no front derailleur anyway. (It has a
crossover gearing setup with two chains, two rear derailleurs, and
twenty-five speeds). Not to be too picky, but about 40 teeth would
be nice. I've been too lazy to write to Durham to ask if they make
them anymore.