Indexing Issues with SRAM Cassette and SunTour Shifters

[hamster]

Are the cassettes the same sizes? DX IIRC was designed for a maximum of 30T. Usually I would say that you can push a couple of extra teeth, maybe this time you are just really unlucky with a tolerance build-up.

 

[DoctorRad]

It's the same with the 8-speed XT rear mech I swapped to, but yes, they were both 11-32 cassettes.

 

[andyz]

Re:

Just tried an M737 cassette instead of the SRAM and it works perfectly! :?

Maybe this has something to do with the SRAM cassette being new rather than a semi worn-out shimano one?

 

[DoctorRad]

Pooooosibly, but I'd have thought a new SRAM chain should shift okay with a new SRAM cassette, which is what I was using. Cassette wear usually leads to worse shifting with a new chain, not better...

Fortunately, HG-51 8-speed cassette are all of a tenner from Chain Reaction

 

[DoctorRad]

Just to follow up on this, I fitted a used Shimano 8-speed cassette to the Xizang, and it was shifting better with the SunTour thumbshifters than the new SRAM cassette. Also confirmed that my mate who tried a similar set-up and couldn't get it to index was also using a SRAM cassette.

Very much a 'who knew?' situation!