18 January 2013

Another Forerunner To A Shimano "Innovation"

For today's post, I'm going to engage in a bit of bike geekery, as I did in yesterday's post.  Fear not:  This will not be a regular feature of Midlife Cycling.  At least, I don't intend it to be.

As I did in yesterday's post, I'm going to write about a long-forgotten component that featured a design used in later, more successful (at least commercially) bike parts.

From the 1920's until the 1970's, many British bikes featured Williams cranks, chanrings and bottom brackets.  That is not surprising when you consider that those parts were, like the bikes, made in England.  

As Steve Griffiths notes in "Classic Lightweights," Williams has been unfairly judged on the basis of its lowest-quality--and, unfortunately, most commonly-used--model, the C34.  It was a cottered steel crankset, and the arms (or spider) onto which the chainrings mounted was swaged (forced).  Willliams also make much nicer models,including some of those thin,elegant cranks you see on British bikes from the 1960's and earlier.  

But their best crankset--and the only cotterless crankset made in any significant quantity in England--was the AB 77. I have seen one of them in my entire life: on a Claud Butler that came into the first shop in which I worked.  

The AB77 was actually quite nice:  the quality of the materials, machining and finish were high.  It had the same chainring design as the TA Cyclotouriste, Stronglight 49D and the Nervar crank that aped them.  That meant the AB77, like those other cranks, could be set up as a road double with a 42 tooth small chainring  or as a triple with a 26-tooth inner ring.  

But the most interesting part of the AB77 was its bottom bracket.  Presaging a trend by two decades, its axle had a splined rather than square end.  In other words, it was a proto-Octalink or ISIS bottom bracket.  

Unfortunately, that bottom bracket was its fatal flaw.  During the period when the AB77 was produced (1962-mid 1970's), only one other crank had such a design.  It was made by Gnutti in Italy and its splines were of a different pattern from Williams', so the two could not be interchanged.  That was especially unfortunate for Williams, because the bottom bracket, which was made by T.D.C. (once a major manufacturer or headsets and freewheels), didn't last very long. 

When Shimano decided to resurrect this long-forgotten idea during the 1990's, it made the splines broader, which was supposed to increase the stiffness as well as the lifespan of the bottom bracket.  However, they, like their TDC/Williams predecessor, wore out quickly.  The problem with the Shimano splined brackets--and the similar, though not interchangeable, ISIS-pattern bottom brackets made by other companies--had narrower axles and smaller bearings than their square-ended counterparts.  Interestingly, Shimano's Octalink and other companies' ISIS bottom brackets had an even shorter run--not much more than half a decade--than the ones from TDC/Williams.  

A few years after Williams ceased production of the AB77, they were taken over by Nicklin,one of their former competitors, which offered only the C34 and a couple of other low-priced models that were fitted to mass-market bikes from Raleigh, Dawes and other manufacturers.  As production of such bikes ended, so did most of the British cycle-component industry, including Nicklin/Williams.  

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