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Discussion Starter · #1 ·
Hi Guys
I have a 07 bike equipped with xtr components. I am having trouble with periodic chain skip under load which produces a loud bang which resonates through my carbon frame like a gun shot. I changed the rear cassette and granny ring as they were wore out as well as the chain. I was hoping this would solve the problem but it did not. Middle ring is only gear left to change as I run a bash guard.

I was advised that the problem could be coming from a worn middle ring. Problem is I can't read the part# for wear on the ring.

What I can see is shimano S G or C ....X....M Can anyone fill in the blanks so I can order a new middle ring?

Thanks for the help:thumbsup:
Straw
 

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straw said:
Hi Guys
I have a 07 bike equipped with xtr components. I am having trouble with periodic chain skip under load which produces a loud bang which resonates through my carbon frame like a gun shot. I changed the rear cassette and granny ring as they were wore out as well as the chain. I was hoping this would solve the problem but it did not. Middle ring is only gear left to change as I run a bash guard.

I was advised that the problem could be coming from a worn middle ring. Problem is I can't read the part# for wear on the ring.

What I can see is shimano S G or C ....X....M Can anyone fill in the blanks so I can order a new middle ring?

Thanks for the help:thumbsup:
Straw
Look for the crank model. Most XTR rings are crank specific.
 

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Discussion Starter · #3 ·
Thanks Pisgah

I just got off the Shimano Tech Docs site and now I have another question. I have the FC-M970 crankset.
I found my ring which is 32ab because it is used in the 44-32-24 combo. Last summer I switched my 24T for 22T because I was riding the 7 Summits trail in Rossland which goes up forever. Shimano shows a 32aa mid ring when going with their 44-32-22 combo.

Should I opt for the 32aa now that I am running a 22T granny? Shifting seems to be okay but maybe it could be better.

Thanks,
Straw.
 

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Discussion Starter · #7 ·
Yeah they are cheaper. I phoned Blackspire and they were really helpful. I will have to buy their granny as well because their middle ring is not compatible with xtr. Still I think I am ahead of the game as far as cost goes. The reviews I found all say they will last longer than xtr so that's another plus. Blackspire wasn't really on my radar other than I knew they made bashguards. Having looked over their site I was impressed. Living in BC I am happy to be able to shop closer to home. I really like their flat pedals, oh well more to buy.
 
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