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I'm trying to find a way to bodge a S.-A. SRF5(W) hub onto a bike with difficult dropouts. There are two main problems (looking at step 6 of this diagram and also at these part pictures p.15,41 will aid in understanding this description, should you care to do so):

Problem 1: The axle is a bit too short to take all the washers and nuts on the right-hand (drive) side.

Problem 2: The bend in the fulcrum arm is not sharp enough to get around the lips of the dropouts.

Solution 1: get rid of the fulcrum arm (see link 2, pg. 41) and just use the locating washer (I think I can probably prang it off with a cold-chisel). I could then cut the fulcrum arm bend off and attach the straight piece with clamps or somesuch to the chainstay. As I understand it the fulcrum arm is not actually resisting rotational forces (that's done by the anti-rotation washers on the flat-sides axle), but instead is providing a place for the mounting of a barrel-adjuster screw to allow tuning of the shift lever.

Solution 2: hope that someone is going to tell me that I can simply using Fitting Kit HFIS5.PHSV (p.15 ) which seems to magically replace the fulcrum arm, gear selector guid and g.s.g. protective cover with two simpler parts.

Solution 3: try to get a thinner, more steep angled fulcrum lever machined for me ... or mock it up out of soft aluminum. It LOOKS as though it's only function is to provide a mounting point for the barrel adjuster screw (see 3.Gear Adjustment of link 1)

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Photos of the actual hub, and the dropout you're trying to work around would be helpful. –  zenbike Apr 15 '12 at 19:00
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1 Answer 1

up vote 1 down vote accepted

To answer my own question:

Solution #2 is good.

It's possible to replace the fulcrum arm and pulley assembly with a short guide nut (HMN420) as long as there's a cable stop somewhere on the frame. You can also buy what S.A. calls "fulcrum clips", see catalogue linked in question above, which effectively provide a cable stop.

This combination has the advantage that it will fit into a tight dropout with deep circular lips that impede the fitting of the fulcrum arm and/or the pulley assembly.

ADDITIONAL INFO: Tony Hadland in his supplement to The Sturmey Archer Story mentions that a different, but similar hub, the Sprinter would work with/out the fulcrum arm, so this is a use-case which S.A. has tried to address for some time:

The Sprinter used the same shell as the 5-StAr; and like the 5-StAr, had the same ratios as the S5 series. However, the Sprinter's arrangements for routing the toggle chain into the hub were novel in that there were four options: the traditional flared wheel nut; or a "gear selector pulley" in a housing which slid over the wheel nut; and in either case with or without an axle-fitting fulcrum lever/clip. These options were felt necessary because of the high cable tension necessary for single cable selection of five gears - which with an ordinary flared nut and banded-on fulcrum clip could give stiff operation and/or cause the clip to slip along the chainstay. However, with a brazed-on cable stop, the flared nut worked quite well.

Whether the SRF5(W) has the same concerns about high cable-tension remains to be seen. One downside to using a fulcrum-clip (e.g. HSJ513 - HSJ514, HSJ548,HSJ543) on three-speed hubs is that the cable can apparently hang loose in certain gears. A suggested remedy is using full-length cable housing.

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