# Chain jumping on the Rear



## breezer69 (Jul 15, 2011)

Hi Forum does anyone have an idea why my chain jumps on the rear derailleur when i force power on the pedals, shifting is no problem. 

SRAM RED rear and front derailleur
Chain is X-SL KMC 

you can see the problem by a video on 

vimeo.com/27113473



Thanks Roland


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## asad137 (Jul 29, 2009)

Does it happen in every rear gear? How many miles on the chain? How many miles on the cassette?

Asad


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## asad137 (Jul 29, 2009)

nm, just watched the video. It looks like your derailleur isn't adjusted properly. The chain isn't jumping on the rear derailleur, it's trying to climb up to the next largest cog -- which means that the derailleur isn't centered below the gear.

Asad


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## breezer69 (Jul 15, 2011)

Hi Asad, 
yes this occurs in every gear when i give power to the pedals.
The chain is new, the cassette should have 100 miles, got it used ! 

Thanks Roland


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## breezer69 (Jul 15, 2011)

I was in a shop which controlled the derailleur should be ok. They said its the cassette which is too old, can't believe that. The chain is not climbing its jumping in the gear when i put energy to the chain.


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## Camilo (Jun 23, 2007)

Do you know how to fine tune the rear derailleur? If so, double check it. If not, it's easy and there are many online guides video and printed - or just reply and I can point you to the ones that seem to make best sense to me.

As for the cassette - unless you have total knowledge of and faith in the seller of your used cassette, you really don't know how worn it is. If it doesn't work right after adjustment, you might have to take the shop's word for it and try a new one. You could post good clear photos of the cassette and some here might be able to advise on the condition.


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## cxwrench (Nov 9, 2004)

why don't you just have the shop throw a wheel from a new bike on your bike and see what happens. that will tell you right away if your cogs are worn out.


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## wipeout (Jun 6, 2005)

I had a weird problem on my new bike w/SRAM Force. Would not shift well at all in the RD. Hanger was aligned correctly and the adjustments were good but it turns out that there was a subtle bind in the RD. LBS swapped out with a new Force RD and shifting is now perfect. Weird.


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## breezer69 (Jul 15, 2011)

thanks i tried a dura ace cassette on the wheel ... perfect, so i'll have to change the cassette i think


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## gpcyclist25 (Mar 22, 2011)

If your hanger isn't bent, it sounds like a simple barrel adjustment on the RD. Since you're getting a problem in every gear, it sounds like a uniform indexing adjustment, done through the barrel adjuster, should do the trick.


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## breezer69 (Jul 15, 2011)

hi gpcyclist i was in three different shops to fix the adjustment but nothing helped. We changed the cassette to a Force model ... gone.
Now i decided to change it to a dura ace cassette.


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## cxwrench (Nov 9, 2004)

it took 3 shops to figure out your cassette was worn? really?


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## Lt. Dan (Apr 15, 2011)

That's strange, sure looked like the cable was too tight by about half a turn to me.


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## ZoSoSwiM (Mar 7, 2008)

Release all cable tension and readjust your high limit.. I had mine too far inward and it cause some funky shifting. Loosened it a bit and it went back to buttery smooth. 

Just don't loosen it too much..


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