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Old 05-12-10, 05:23 PM   #1
diddidit
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Does KMC chain shift as well as Shimano or Sram?

My wife's Cannondale Synapse mixes a KMC chain with 105 3x10 derailleurs and a Sram cluster. She's got ghost shifting issues and general noise from the RD, both of which I can confirm from riding with her. On the stand I can't duplicate the ghost shifting, but the noise I can. I've tweaked and adjusted and even given dirty looks, but I just can't settle the thing down to be as quiet as my 7800-equipped bike.

It looks like the noise comes from the chain juuuust catching on an adjacent tooth of the next-larger sprocket, and then uncatching. It's most prominent in the smallest sprockets, especially when in the middle ring.

On a hunch, I measured the KMC chain, and compared it to new Shimano and Sram chains; the KMC measures ~6.1mm, while the others are 5.95mm (assuming I remember how to read a vernier caliper right). Dunno if that matters, and I think I recall that Shimano's spec is 6.1, but it's interesting nonetheless.

So, ideas? Anyone think a new Sram chain would help?

Thanks -

did
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Old 05-12-10, 05:28 PM   #2
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too much tension, or something is bent
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Old 05-12-10, 05:54 PM   #3
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It's a trim issue of some kind. Either the RD is mis-adjusted mis-aligned. Mis-alignment can be the result of a bent hanger, or because of a twist or bend within the RD itself.

The other possibility is that the chain is the wrong type, as in 6s for a 9s system and it's too wide.

Determine which by looking at the chain at the top of the cassette. If it sits nicely on a sprocket and clears the adjacent one, you know the chain is fine, and it's the RD that's feeding it to the cassette improperly.
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Old 05-12-10, 05:58 PM   #4
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OK, tweaked a bit more. Amazing what a difference having some dinner makes! Actually needed more cable tension, then fine adjustments. Hits 'em all quietly now - we'll see how it goes on the road, but it's better on the stand now.

Thanks for the sounding board...

did
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Old 05-12-10, 06:29 PM   #5
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Does a Shimano chain made by KMC shift as well as a KMC chain made for Shimano?

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Old 05-12-10, 07:42 PM   #6
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Probably KMC chain made by KMC and sold under KMC brand shifts better and last longer than anything in the market right now.
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Old 05-12-10, 07:50 PM   #7
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I buy, use, sell and recommend only KMC chains. They offer the best value and have the easiest to use master link. Glad to hear the adjustment quieted the beast!
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