Sciguy 

The Sram Rival bar end shifter for the rear 10 speed derailleur on my wife's TT bike is beginning to show less positive indexing than it use to have. I'm wondering of there is a technique one might use to revitalize the indexing outside if purchasing a whole new unit.

Thanks for any informed replies!

Hugh

Retro Grouch 

I doubt it's the shifter.

If you can't get it right with a basic cable tension adjustment, I'd start by having the derailleur hanger alignment checked.

corrado33

I agree with @Retro Grouch. It's almost never the shifter, unless the bike has sat outside for a long time.

However, if it IS the shifter, a simple bath in WD-40 (or your solvent of choice) (of the mechanical parts) then subsequent re-lubrication should bring it back to it's former self. Even better if you can put the shifter in a small cup then put the cup and shifter in a sonicator (jewelry cleaner.)

Sciguy 

Thanks for the quick reply.

I can get the shifting just fine. It's the strength of the detent that's troubling. As if it's almost in friction mode with the slightest of "clicks" for the individual detents. Sram doesn't support friction mode so it's not that that's partially engaged. I'm wondering if the individual nubs on the detent ring are just too worn down. I assume one doe not want lube inside this mechanism and wonder if spraying some brake cleaner in to clean out the somewhat slippy guck might help?

Hugh

dsbrantjr

Brake cleaner can attack plastic parts; I wouldn't use it unless you are certain that there are none inside.

Edit: Many detent mechanisms use a ball which rides along a number of "divots" which provide the index stops. Perhaps you have lost one of your balls!

Sciguy 

Good point about plastic and brake cleaner. The Sram system uses a somewhat rounded bump on the end of a spring that engage the indents on an inner wheel. There are no ball bearings involved. I'm hesitant to increase lube in the system worrying that it might increase the problem. Since WD-40 is more a solvent than lube I may go that route as an experiment.

Thanks for the advice.

Hugh

RubeRad

Didn't seem to be a problem for Lance...

corrado33

Considering the mechanism, I'd try to find a replacement sprint behind the "ball."

Alternatively, increase the depth of the "divots" would counteract the effect of the ramps wearing.

Sciguy 

The ball like end is part of the spring ....they aren't separate.

Filing or grinding solutions are on the extreme end of what I'm willing to attempt. Before getting to them I'll exhaust the clean/delube/lube possibilities.

Thanks for the thoughts/

Hugh