[CR]Sturmey axles, was Looking for Hilary Stone.

(Example: Framebuilders)

Date: Tue, 18 Jan 2005 21:21:29 -0500
From: "HM & SS Sachs" <sachs@erols.com>
To: johnspeare@gmail.com, classicrendezvous@bikelist.org
Subject: [CR]Sturmey axles, was Looking for Hilary Stone.

John Speare wrote: Hi, I have been told that Hillary Stone watches this list and I am looking for him about fitting a Sturmey-Archer hub onto a bike with 130mm dropouts. If anyone else on this list has advice, I'll take it. Here's the post that I sent to the iBOB list: >From my measurements, the hub has an axle length (measured from where the bolts that screw onto the hub itself) of 110 mm. My frame however, has rear spacing of 130mm. Although I can put 3 mm spacers on each side and still muscle the hub onto the bike, the effective length is only 116 then. I'm a big guy and I don't want to muscle the hub on by "cold setting" the frame 14mm. <snip> +++++++++++++++++++++++++++ 6-1/4" axles were available for the common AW and FW 3- and 4-speed hubs. 6-1/4=158 mm is long enough. I'd ask some other questions before going ahead, though.

Please, remember that the Sturmey axles are not simple bending structures. They're not only bored through, but flatted at the ends (thinner vertical than horizontal), and have long cut-outs near the center. Using the longer axle with spacers outboard just moves the bearings inboard. If this were my project, I would use an extra nut outboard of the spacers but inside the drop-out, to preload the washers and convert those parts, at least, into a larger diameter and thus much stiffer axle. (On a QR axle set, the skewer is a tension member that has the same effect as I'm proposing, but on an S/A the hollow innards are just space for the controls, and can't help stiffen the axle).

At my weight (about #190), I worry about these things. But, I'm not a materials or structures guy, and am telling you about my instincts, not doing an engineering analysis. I do remember a lot of bent flatted-end axles on 10-speed Raleighs we raced at Rice in the early 60s. I guess Raleigh flatted the axle ends on the early Gran Prix and Super Course (?) because they sold the same frames with Sturmeys, or just out of cussed habit, but I had friends who whipped out Chrome Moly versions at the school shop instead of filing open the slot a silly mm or two.

your mileage may vary.

harvey sachs
mcLean va