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From: neal@druny.UUCP (Neal D. McBurnett)
Newsgroups: net.bicycle
Subject: Re: Biopace and PowerCam
Message-ID: <1415@druny.UUCP>
Date: Fri, 12-Apr-85 14:46:39 EST
Article-I.D.: druny.1415
Posted: Fri Apr 12 14:46:39 1985
Date-Received: Sat, 13-Apr-85 04:49:08 EST
References: <114@yale.ARPA>
Organization: AT&T Information Systems Laboratories, Denver
Lines: 17

As I understand it, the Biopace has an ellipse which is effectively
90 degrees out of phase with the others.

This article suggests that "the crank spins more slowly
from 1-5 o'clock,..." for the PowerCam.  The Biopace is exactly the opposite:
during the power stroke (say at about 4 o'clock) the crank spins
more easily ("faster", "more efficiently").  Their objective
is to reduce the knee strain during that part of
the stroke when some crucial muscle groups are changing from contracting
to relaxing, and vice versa (see one of the "Bike Tech" back issues for
LOTS of details).

Thus, it makes no sense to compare the two, or to say that one is
"closer to optimal" than the other: they depart in fundamentaly different
directions from the traditional circular chain ring.

-Neal McBurnett, ihnp4!druny!neal, 303-538-4852