Re: [CR] Current Discussions of Spindles - No mention of BB shell widths ?


Date: Tue, 16 Feb 2010 11:01:49 -0800
From: verktyg <verktyg@aol.com>
To: hfbirm <hfbirm@bellsouth.net>, <Classicrendezvous@bikelist.org>
References: <387714.1040.qm@web53602.mail.re2.yahoo.com> <68011.77258.qm@web180302.mail.gq1.yahoo.com>
In-Reply-To: <68011.77258.qm@web180302.mail.gq1.yahoo.com>
Subject: Re: [CR] Current Discussions of Spindles - No mention of BB shell widths ?


As I pointed out in a previous post, in those days manufacturing tolerances for bicycle components were not very close. For example I measured 3 TA 344 spindles that were supposed to be 116.5mm wide, they were all about 114.6mm wide. A TA 373 that was supposed to be 120mm wide was 117.7mm.

Stronglight made spindles for doubles in 118mm, 120mm, 121mm and 123mm wide. In general, the Stronglight spindles that I've measured have been closer to specs.

Trying to "accurately" measure the width of the center sections of these or any spindles from those days with standard hand tools can be an exercise in futility - I've tried it! They can be easily checked on an optical comparator though.

Sutherland's 5th Edition has those specs listed but they've rarely matched the dimensions that I've come up with. BTW, I have over 35 years in manufacturing and I've been involved with the measurement of parts with dimensional callouts down to 1 micron tolerance - 0.001mm or 0.00004".

As far as cups go, according to Sutherland's 5th again, Stronglight Italian cups are 0.5mm thicker than French cups but the same thickness as British?

TA Italian cups are 1mm thicker than French but only 0.5mm thicker than British!

I think that Sutherland's specs on these parts were taken from actual parts measurements and perhaps the sample quantities were not very large.

The old Europeans who designed and made these parts are probably shaking their heads over folks in quest of the "Golden Mean" for bike part dimensions.

A difference of 1-2mm is less than 1/8" and pretty insignificant in an open chain mechanism such as found on bicycles.

To muddy the water further, start measuring the widths of your BB shells. You'll find that a lot of them are undersized too! Back in the day if the BB shell was too narrow or you needed to make a minor adjustment on width you used a spacer behind the fixed cup.

Just make it work baby!

Oh, and I don't recall seeing many if any Italian bikes that came standard with TA cranks but in the early 70s some such as the mid range Torpados came standard with Stronglight 49 or 93 cranks.

I guess that for the Italians it was cottered steel or Campy cotterless so Stronglight fit the bill.

Chas. Colerich - Officially OLD! So now I can truly be a Retro Grouch! Oakland, CA USA

hfbirm wrote:
> If someone has an English/French Stronglight 118 that they would like to measure flange to flange [width], I'll measure my Italian Stronglight 118 for comparative purposes. To cut down on back and forth, I'll be measuring mine from the "outside to the outside".
>
> Jim Carter
> "the French metric manufacturing standards were right"
> living way above my means in
> Mountain Brook, suburb of
> Birmingham, Alabama
> United States of America