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renaissance cyclist
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309 Posts
Discussion Starter · #1 ·
I recently bought a Jamis Dakar XC. So far, I love it other than the constant chattering of the derailed banging against the chain stay. At first I thought about trying to move the derailed to a position where it won’t be so close to the oddly shaped chain stay of my bike. When I looked at the picture on the Jamis website, however, the Derailed sits very close to the chain stay on that bike too. I’m a little hesitant to change things because the bike really does shift beautifully and I don’t want to mess that up. I’ve had other full suspension bikes and although the derailed did hit at times, this is totally different. Should I just learn to live with the chattering sound when I ride down the trail, or will this eventually ruin my derailed? http://www.jamisbikes.com/usa/thebikes/fullsuspension/dakarxcr/09_dakarxc_sl.html#
 

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Anti-Outsourcer
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319 Posts
That's probably not the rear mech, as that's all held in place by spring tension. What you're probably hearing is chain slap, or the chain bouncing down and hitting the chainstay. Get yourself a neoprene chainstay protector, or something similar.
 

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renaissance cyclist
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309 Posts
Discussion Starter · #3 ·
I got on my knees, lifted the tail end of the bike so that the rear derailer was right in front of my face, and shook the bike to make sure the derailer was knocking on the chain stay, It was. Is it possible that the derailer has a problem causing it to swing around more that it should?
 

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From the picture, it looks like a poor design by Jamis. Post this on the Jamis forum to confirm that they all do this.

A few wraps of an old tube zip tied in place should quiet it down.
 

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This is a common problem with Horst link bikes which have a pivot on the chainstay in front of and below the rear axle. Your Dakar is not Horst link, but unfortunately the chainstay dips down in a similar manner.

There are really only two fixes. Pad the derailleur or chainstay, or both, where it hits. Or get a Shimano shadow-type derailleur (or switch to Sram), these derailleurs have a different geometry that avoids this problem.
 

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I have the Jamis Dakar XC Pro - very sinilar to the XC and had the same issue with mine, it was the derailer hitting the chainstay not the chain. I recently upgraded my rear derailer to the Shimano SLX and it mounts in a way that eliminates the problem. I think the Shimano XT would do the same since they are both based on the 'Shadow' design as they call it. Shifting is noticably nicer with the SLX so I got double benefit.
 
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