Author Topic: Making a 4-speed Sturmey-Archer shifter work on flat bars  (Read 1161 times)

rogerzilla

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Making a 4-speed Sturmey-Archer shifter work on flat bars
« on: 04 June, 2010, 09:15:14 pm »
Well, that was a long job.  You can't use a 4-speed shifter on flat bars because they were designed to go on the outside of a curve - on flat bars the lever hits the bars before you can engage lowest gear.

So...file off the rivet heads holding the clamp in place, and knock out the rivets.  Then you realise you have to prise the thing open (they're chromed brass) to get the bits out.  No matter, because one of the rivet holes has to be opened out to 5mm for an M5 hex head bolt.  This needs two of its flats filing to make it fit in the 7mm width of the bottom of the shifter body, where it becomes a captive non-rotating bolt.

Then, with great difficulty, you put the gubbins back in, locate the rivet you removed and squeeze it back together in a vice, being ultra-careful not to mark the finish (I wrapped the vice jaws in a teatowel).  A bit of gentle panel beating with a hammer gets it looking like it should again, with a nice even width.

Then it hangs in front of the bars on a 22mm P-clip, rather like a Brompton plastic shifter, and "1" is accessible.  Simples (not).  Quick mock-up to show how it works:






Hard work sometimes pays off in the end, but laziness ALWAYS pays off NOW.