Brompton 2 speed shifting issue

[Fields Electric]

Just sorted out an issue on mine, it refused to shift to the smaller sprocket. But twisting the shifter outward by hand would get it to shift. I put a bit more slack in the cable, which solved the issue. It was only a problem with a worn chain. But it’s been there since new, some 5000 miles ago. I am currently trying to get 1200 miles out of a chain. Sprockets and chain ring are definitely past there best.

 

[rogerzilla]

The wearable parts of the derailleur mechanism aren't particularly expensive, just a bit fiddly to fit (the cable is particular fun, especially if you use a generic SA trigger cable as the inner wire). The external spring tends to rust, so it's worth an occasional replacement.

 

[berlinonaut]

The wearable parts of the derailleur mechanism aren't particularly expensive, just a bit fiddly to fit (the cable is particular fun, especially if you use a generic SA trigger cable as the inner wire). The external spring tends to rust, so it's worth an occasional replacement.

Worth mentioning that, once more, you seem to refer to an outdated design. Brompton changed the design of the shifter already back in 2017 and along with that came a new dogleg which makes changing the derailleur cable way easier than with the old design.

 

[rogerzilla]

True, but there are probably as many pre-2017 Bromptons about as post-2017. They still sell the old type of dogleg mechanism, too - I've just fitted a new one to a 2005 S6L.