Are these the Bullseye rings?
http://www.firstflightbikes.com/
Would you have needed a super long cage derailleur? Like this?
http://www.firstflightbikes.com/
Wasn't there a third Biopace? Biopace HP (high performance) that was even closer to round.
Thanks
Jeff Archer
First Flight Bicycles
216 S. Center St.
Statesville, NC 28677
704.878.9689
704.878.9683 FAX
firstflight@abts.net
http://www.firstflightbikes.com
> I must abstain from the uniform heckle that these much maligned chain
rings
> receive.. In fact, let it be noted that condemnation of these chain rings
is
> universally conformed to by all with-it cyclists..
>
> BUT let's review the theory that propelled Shimano to spend so much time
and
> money promoting BioPace..
>
> It was decided, in the Shimano R&D department, that the natural circular
> pedaling action didn't use all the muscle systems in the legs properly..
That
> some muscles are stronger and others weaker or in a position not to be
> effectively used in the pedaling action. The down stroke was the
strongest
> and the back of the stroke was the least useful. Rather than oblige riders
to
> learn a difficult technique (learn Spinning, acquire "Souplesse", or
> whatever) they decided to design chain rings that optimized the down
stroke
> and minimized the rest.
>
> The Biopace chain rings are elliptical and "lobed" to emphasize the power
> stroke and "slip through" the back stroke. (Incidentally, elliptical chain
> rings are an old concept and have been revisited many times in cycling
> history.) In use, the BioPace chain rings cater to novice riders and/or
> tourists who pedal more slowly and tend to put more emphasis on the down
> stroke. This obviously was the anathema to experienced riders who had been
> constantly urging neophytes to pedal "correctly."
>
> Back in the late 1970s, I receive from Wayne Stetina at Shimano one of the
> first sets of BioPace chain rings brought into the USA .. He wanted me to
> ride them and provide feedback. I mounted the crank set on my McLean
touring
> bike and after rode for a few months (back in my more active days!) I
noticed
> the odd loping effect, bobbing almost, as one pedaled but adapted to it
> quickly. Eventually I got to not mind that effect at all and maybe believe
it
> wasn't all that bad.. But the BioPace definitely doesn't encourage high
rpm
> pedaling and perhaps encourages chugging along in bigger gears than one
ought
> to be using.
>
> So, historically they are interesting, but functionally BioPace was
probably
> a hindrance to advancing in technique and pedaling style.. But also not a
> total joke to my view....
>
> Dale Brown