Pulley/jockey wheels issue

[rbike]

I mounted a XTR RD-M952 rear derailleur (previousely had Shimano STX RC) and there seems to be a problem regarding chain compatibility (if that is even possible). Chain is Shimano HG, cassette SRAM PG 850.

When the chain goes around the pulleys, it makes kind of grinding noise, that is difficult to hear, but you can easely feel it if you rest your fingers on the chain when it goes around the pulleys. Also chain links seem to be a little too long - chain does not engage in the middle between two teeth. I checked on another bike with Shimano STX RC and chain runs much more smoothly and engages in the middle of the two teeth...in fact perfectly comparing to XTR. I checked chain wear and is not new, but should be within tolerances.

Have I missed something? I thought that chain links are all the same length between groups...or could it be something with the fact that XTR has larger (11 teeth) pulleys?

Just a link to a thread would be fine...

 

[scottproonly]

Re:

It might be because an STX chain is too wide for an XTR rear mech.
Kes

 

[Stiff_Orange]

XTR M952 is 9-speed. STX-RC and Sram PG850 are 8-speed

What type of HG chains is it. They come in it 7/8 speed or 9, 10 or 11 speed versions. 7/8 speed are interchangeable but the others aren't. You might be able to use a nine speed chain with the PG850.

Check out this document it's for modern shimano but it shows the what is and isn't compatible :-

http://productinfo.shimano.com/download/pdf/com/1.0/en

 

[Stiff_Orange]

Also have you checked the chain wear? If it has stretched, then the teeth on the 'new' derailleur won't engage properly.

 

[Muddy paw]

Can't you just put the old jockey wheels on for now ..

 

[rbike]

Thanks for replies.

I was using this XTR derailleur on the other bike for the summer. Same components, PG850, chain is different (only written SHIMANO HG NARROW) and in better shape (145,2mm (5,72in) between 13 rollers). Too bad I did not look at derailleur closer, however I did not notice this grinding when cleaning. Everything was working ok. Shifting was great, so I guess it works fine with 8 speed (Shimano STXRC shiffter).

On this bike the chain is CN-HG40 NARROW. Wear is 145,5mm (5,73in) between 13 rollers. I It was working fine with STX RC derailleur, I measured the between two cages width (instead dismounting the pulley to measure width) and STXRC is narrower than XTR. Chain does not touch cage.

When do you change your chain? I change it when between 13 rollers is 145,9mm (5,74in). So 145,5mm (5,73in) is still ok...

For now I can just use the other bike ))

 

[Muddy paw]

I generally change my chain and jocky wheels every 12 months normally for piece of mind and i find i have very little issues with cassettes and chain rings as far as wear an tear is concernd and i've never really measured chains properly but i have put old against new to compare how much the old one has stretched but in reallity a chain doesn't really stretch as much as you'd think as the main issues with chains is the link pins wear making them slightly smaller than the holes in the link plates causing excess movement ..

 

[Thias]

1) you measured the length. That is an indicator to the wear of a chain. But you also need to measure the width. 8speed chains are wider than 9speed chains.
2) Grinding might also be the b-tension screw not adjusted correctly (too loose)

Hope this helps.

 

[legrandefromage]

It sounds like your chain is pooped and has stretched. All chains are the same measurement between links as the bleow pic shows..

You can run 8spd chains inside 9spd mechs quite happily, I'm running 9spd Ultegra with an 8spd and theres no clearance issues. same with a M570 LX mech on another bike. I've been running 9spd in 7/8spd systems for years as sometimes 9spd chains have been cheaper than 8.

 

[02gf74]

Re:

Chains are the same distance between when new.

Buy chain wear gauge, more accuraate than measuring. Replace at .75 percent.

Without seeing (hearing) the issue, ill be surprised if it teeth on jockey wheel, these plastic wheeks dont look like theyre cnc precision teeth.

Seem to recall shimano have 10 t , check the extra tooth is not causing chaing to run in mech.