From: harry@cv.hp.com (Harry Phinney)
Newsgroups: rec.bicycles
Subject: Re: top five innovations
Date: 3 Sep 92 19:42:51 GMT
Article-I.D.: hpcvusn.1992Sep3.194251.8768
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
X-Newsreader: Tin 1.1 PL4

tomk@netcom.com (Thomas H. Kunich) writes:
: The statistics that Shimano used were inferred from several 
: articles in all of the major bicyle rags in about '89 or so.

There's no need to infer what statistics were used in the development.
Their research was published in Bike Tech Volume 2, Number 4 dated
August, 1983.

: At that time Shimano was trying to develop a group for the 
: 'average' road rider and was interested in having some sort of
: market distinction. None of these is deceptive nor stupid. This
: is very simple marketing that any first year student learns to use.

Is it not deceptive to claim a significant performance enhancement for a
product which does not in fact provide such an enhancement?  This may
indeed be something learned by first year marketing students, but that
does not justify it.  Biopace was not targeted only at "average" riders.
One of their US marketing people (Wayne Stetina) used a Biopace inner
ring in winning a national road championship, and made sure people knew
about it.

: Biopace _does_ seem to have a positive effect at very low cadence.
: Mountain bikes used the 26 ring to pretty good effect. Had there
: not been mechanical difficulties with making a 24 they probably could
: have retained that market indefinitely.
: 
: BTW, many riders had noticed this. This isn't an implication, but
: a fact.

No, it's not an implication, nor is it a fact.  It is an opinion which
you hold, and nothing more.

: 'Somewhat incorrect' is the correct term since
: the only problem with it was that the 'average rider's cadence' was
: assumed to be the average _japanese_ rider's cadence.
: 
: In Japan, many japanese commute via bicycle and have very low cadences
: of around 45 RPM.

There is no reference to a cadence of 45 RPM in the published research.
The lead-in paragraph bemoans the fact that "the riders of the Tour de
France eat about the same as the riders ten years ago, and cover a
little less ground in their 24 days than did their predecessors."  It
then goes on to ask "Has there been no improvement at all?"  The only
data presented is a graphical representation of joint torques and
electromyograms for one individual (the author - Shinpei Okajima) at a
load equivalent to climbing at 24 km/h on a 4% grade with cadences of 50
and 56 RPM.  It is not made clear whether these graphs represent the
result of one particular run, or a composite of several.  Neither is it
made clear whether all tests were run at the same loads and cadences,
although I suspect not.  While the joint torque graph shows some
noticeable differences (the Biopace results in generally lower peak
joint torques, but less smooth variances), the electromyograms are about
a wash, with (IMO) a little less activation in the case of round
chainrings.  The data presented is far too little to draw any
conclusions.  Nowhere in the article does it imply an optimum or maximum
cadence for the chainrings, nor does it state or imply that they are
more effective at lower cadences.

There was apparently no investigation into possible efficiency gains,
despite the tone and topic of the introduction.

: As for overwhelming evidence -- maybe you can find some? All of 
: those 'scientific' theories were sound but the tests were generally
: completely flawed -- as evidenced by the football shaped rings
: most commonly on sale.

Actually, Okajima describes a somewhat idealized model of the human leg
in pedaling, and from this derives a velocity pattern for optimum power
transfer.  He states "The assumptions made here might in principle have
made the result inaccurate, but we later obtained similar results with
the actual mechanism.  We estimate that this information is applicable
except in the case when the hip socket is not kept stationary."  Later,
however, he admits that "Among mechanically practical velocity
patterns, it turns out that the simple approximate sine-curve provided
by the familiar elliptical chainwheel can come about as close to the
<optimum velocity pattern> as does any other."  He states that Biopace
deviates from an elliptical shape primarily in an attempt to reduce
the leg acceleration at the point where the muscles in the knee must
switch between active muscle groups.

: Not everyone in this world is out to screw you personally Jobst.
: Most people are trying to make a living and Shimano is at least 
: supplying high quality at low prices and most people agree with them.

I like a lot of Shimano's products, and will admit that they make some
of the best parts around.  They also have produced some of the worst
junk ever pushed on otherwise ignorant consumers.  Have you ever (tried
to) worked on a FFS (Front Freewheel System) bike?  Have you ever tried
to make a Positron derailleur "index"?  Tried to get brake pads for your
AX equipment lately?  While screwing people is undoubtably not high on
their list of priorities, they've none the less managed to do so many
times.

Harry Phinney   harry@hp-pcd.cv.hp.com