thumbshifter slipping

christopher247

Hi

I'm trying to fix an old bike with thumbshifters. The chainring thumbshifter is slipping and moving the chain from the big to the small chainring, even when I apply pressure to move it to the big chainring position. They are friction shift.

Any ideas?

Thanks

Chris

Chunkers1980

Fiction shift would actually be better to sort out.

Indexed you've got a problem. You need some way to clamp it harder to the indexing system.

redvee

There should be a thumbscrew to tighten the LH lever or it might be a phillips screw. What shifters are you using?

christopher247

There was a thumbscrew, and I've tightened it! Thank you!