From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Why don't pros shellac their tubulars?
Date: 3 Dec 1997 00:12:48 GMT

Mark McMaster writes:

> But the differences in rolling resistance have been measured, and
> while small, can amount to many seconds over a 40K TT.  Since TT
> time differences between the top pros is also within seconds, you
> would think that they would want to take advantage of this, at least
> in critical events like TTs.

I bet that for important record events like the hour, all stops are
pulled out and tires are secured with hard glue.  On the other hand,
it is possible that bike types don't know why there was "track glue".
I recall clearly that those who used it when I was first interested in
the subject, thought it was to prevent tires from rolling off on the
track "where side forces are much greater due to bankings".  It was
only later when working with Avocet and IRC that the glue losses came
to light that I discovered why there was "track glue".

> Okay, perhaps shellac is not ideal, but why not use some other type
> of hard adhesive (rather than a soft adhesive, which can soften
> under the heat of braking and can absorb tire rolling energy)?

I don't care what you call it, it looks like shellac and hardens like
shellac.  The Clement or Pirelli Pista cement was dark amber colored
and had all the other features of shellac except that it was thick like
partially dried out shellac.  Track tires also had bare cloth strips
in contrast to road tires that had latex or other elastomer coated
strips made to stick to pressure sensitive adhesives.

Jobst Brandt      <jbrandt@hpl.hp.com>