Lockring for F&S toggle chain
 

My 2004 Brompton has a Fichtel & Sachs 3 speed hub.
It is missing its locknut (N in the attached diagram), so adjustment is tricky.
F&S toggle chains use a very odd 5mm x 0.70 threading.
Anybody know where I can find a locknut or toggle chain+locknut set.

Amir

https://cimg5.ibsrv.net/gimg/bikefor...35fbc69eeb.jpg
https://cimg6.ibsrv.net/gimg/bikefor...2734b0720e.jpg

SJS Cycles in UK is one Place to ask . I guess, but I'm not even in England,

so no guarantees ..

Is that the same thread as older Sturmey Archer three speed hub gear chains.

Sram Bought out Sachs, so Fichtel & Sachs is dissolved..

Recently they, Sram, Dropped the internal gear sector entirely..
insufficiently profitable I suppose..


good luck with your search , ... it is now out of production..

might as well just get a new Brompton BSR wheel ..
their new directionally drilled rear rims are better too.



...

Do your adjustment, then measure with a ruler (or caliper) the distance, back it out 5mm and apply loctite. Then screw it back to whatever distance you measured. Next time you need to recalibrate, you need to weaken the loctite with a hair dryer. Maybe it will hold. (If not, then there is red loctite.)

no. S-A toggle bolt has a smaller diameter. They are not interchangeable

where have you tried to find Sachs,Sram parts , so far?
1.
2.
3.
It is mechanically possible, to tear down the hub and add a sleeve of metal in a larger hole
of that internal piece that does the shifting
then re thread it in the smaller thread standard of the remaining SA indicator chain ..

Likely less effort to do as I said above, Buy..
" might as well just get a new Brompton BSR wheel ..

Yes, their new directionally drilled rear rims are better too."

I found the new hub & shifter, Mk4, easier than the AW3/steel trigger in my prior Mk2..





...