I have two with the 12 spline pattern, a 49 FM and a 52 AM. I have also seen the 3 spline pattern from this era as well.? My 51 FW and 53 Am both have the 3 spline cog.
Regards, Troy "?" Warnick Olympia, WA
>From: Sheldon Brown <CaptBike@sheldonbrown.com>
>To: "Hilary Stone" <Hilary.stone@tesco.net>, Troy Warnick
><twar@hotmail.com>, classicrendezvous@bikelist.org
>Subject: Re: [CR]Sturmey cog needed
>Date: Sat, 12 May 2001 17:05:17 -0400
>
>Hilary Stone wrote:
>>Sturmey Archer's hubs in the 1940s and 1950s used two types of sprocket -
>>screw-on mostly on their basic AW and AB, FWs, etc and a 12 spline
>>sprocket
>>on their upmarket hubs FM, FC, ASC, AC etc. This was also used on their
>>pre-war 2-speed fixed hubs TF, TFB, T and TC, and the 3-speed KS and KSW
>>hubs. The familiar 3 spline sprockets were fitted from 1957 onwards right
>>across the range of hubs. But the pre-war hubs can only use the 12 spline
>>pattern - this isn't strictly true as the 3-spline sprockets can be
>>modifified just a little with a Dremel and fit on the 12 spline drivers.
>>Post war hubs can have their drivers changed for later 3 spline drivers
>>and
>>that is a very simple operation.
>
>I have occasionally seen the 12 spline type on very old hubs, but I
>believe the changeover to the 3-spline type happened well before
>1957. Indeed, my '52 ASC uses a 3-splined sprocket, and I've seen
>lots of late 40's hubs with these. I've paid attention to this for a
>long time, as I used to be diligently hunting for the older threaded
>drivers for use with hybrid gearing (I've gotten as many as 7
>sprockets onto S-A hubs this way.)
>
>Pre-war S-A hubs are extremely rare in the U.S. British bikes were
>mostly unknown here until returninv veterans started bringing them
>home aftwer WWII
>
>Sheldon "Hercules Stuck With Threaded Drivers Long After S-A Ditched
>Them" Brown
>Newtonville, Massachusetts
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