From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Paired spokes (aka Rolf)
Date: 8 Dec 2000 21:22:39 GMT

Willie Martins writes:

> What is your opinion of the new tendency towards paired spoke
> design, as used by Shimano and Rolf, perhaps a new thread or if you
> have already posted give me a pointer.

Shimano couldn't bear to see Trek run away with the boutique wheel
business and came out with their own magic design.  I was amused by
this and admire Shimano for their inventiveness, considering that they
had a major patent problem to overcome.  They did it and added an
equally useless but clever feature of cross-over spoking where the
left spokes got to the right side of the rim.  Their spoke elbows
hanging from the thin side wall of the rim cause wrinkles and
interfere with brakes, but hey, they got around the patents.

Nya nya, see if you can top that Trek!

The whole paired spoke idea grew out of Rolf Dietrich's
dissatisfaction with the 'overweight' low spoke count wheels of
Campagnolo as I see it.  In his patent and from observing his first
wheels, he seemed to believe that the aero rim profile depth was there
for the aero effect and didn't gain much but lost a lot in too much
weight.  So he got a light weight rim and spoked it up with 16 spokes.

Well, that won't do because the spokes have to be damn tight to hold a
load when there are so few.  So when the spokes got tight enough the
wheel was a wavy-S from spoke to spoke.  Oops!  That's when the idea
for paired spokes surfaced and there would be no zig zag.  That may be
the case but now, unbeknownst to Rolf, he had humps in the long span
between spokes and these actually went to market.  I don't know what
Trek did about them but they cracked at the spokes because the humps
flexed enough to fatigue the rim in bending.  Subsequently the rims
got heavier and we are back to square one.

Since wheels building is done by machine, paired spokes come with
added expense because a machine doesn't get to such closely paired
spoke nipples.  Hence, we have the Sestrier and Vector wheels that are
getting close to conventional 20 spoke wheels.  The feature is
gradually evolving into the tried and true.

Jobst Brandt      <jbrandt@hpl.hp.com>