Kezzzzz

I am having a problem with chain drop off the big ring on a 2nd hand bike I bought. Sram red 10spd.

The chain keeps on jumping off the big ring and if I adjust the H limit to sit closer I can't shift from the small to big ring.

What I have tried:
- reset the derailer position, straight and just a few mm off the big chain ring
- set the L limit screw whilst on the small ring
- tension the cable by hand whilst on small ring
- moved to big ring, adjusted the H limit screw. It was pretty far out.
- problem, now i can't shift from small to big ring.
- I let the H limit screw out, I can shift again, but the gap is large and I drop chain off big ring quite a bit.


​​​​Can anyone help me troubleshoot this? TIA

cxwrench

Which Red front derailleur do you have? The Ti cage one that was the first version?

Kezzzzz

Yep, I believe it was the first version. This is a 2015 sworks venge bike build.

I would post a photo but can't do it yet (too new to the forums)

cxwrench

If it's this derailleur:



Throw it away and buy a current model. ^This^ derailleur was awful, very flexible and the shape of the outer plate (not curved) caused all sorts of problems w/ thrown chains. If you're using the one shown with a compact crank it's even worse. The angle of the cage plates was ok with standard chainrings (53/39) but needed a 3* shim to work well w/ smaller rings.
ETA: This thread should be in 'bicycle mechanics' for obvious reasons, not GD.

Kezzzzz

Thanks heaps for the help. I did have an old titanium from derailer and purchased a new one and installed it just now. 10 fold better result.

Thanks and appreciate your help.

Admin, please feel free to move to mechanic's.