From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Aluminum derailleur pulleys?
Date: 21 Jan 1998 18:44:48 GMT

Brian Dempsey writes:

> I agree with Jobst in his point that the 'centeron' pulley does
> nothing to aid the shifting to larger rear cogs.  The 'lagging
> detent' however is NOT what Shimano uses to permit thier indexing to
> work.  It is true that the shift lever returns somewhat after
> completing the motion to the next detent and being released, but a
> new or good condition Shimano drivetrain will properly index EVEN IF
> you shift to the next detent while NOT spinning the cranks, NEXT
> release the lever, and THEN resume pedalling.  Clearly if the index
> functions without pushing the lever past it's resting place in a
> detent, they do not require the 'overshoot.'

The difference is that they use elastic waistband, belt and suspenders
to do it.  The sprockets are murdered to fragile dimensions to make
their ramps possible.  If you try this exercise with some old flat
faced sprockets, you'll find it doesn't shift.  Shimano is pandering
to the well monied middle aged fitness riders who never learned to
shift.  These people have the money and they buy lots of bikes.  The
rest of the bikies get to put up with the watered down equipment with
chains that can't be opened and re-closed with their own pins and
whose sprockets wear out in half the time but cost twice as much.

These are also the people who brought us dual pivot brakes that are
apparently ridden in races with the QR open because the mechanical
advantage is so high that there is no pad clearance.  All this for
people who can't operate a 4:1 brake without complaining of the
excessive muscular strain.  To make up for that, on a long descent in
the rain, these brakes run out of hand lever travel from pad wear.

Jobst Brandt      <jbrandt@hpl.hp.com>