XT Rear Derailleur keeps shredding cables

My xt deraileur M772 is destroying my cables almost exactly at 2 week intervals. Im at a loss at what to do, at first I thought I was tightening it too tight, so I had a lbs torque it down for me..and what do you know another two weeks and its broken again this has been going on for at least 6 weeks #-o! Some one told me this is common with this XT model, anyone else have a similar problem or a good fix?!?

 

No, it's not normal.

I think the most common reason for fraying cables is repeated tightening and loosening of the clamp. Figure out where it needs to be ahead of time, and clamp the cable ONCE. If you loosen it and tighten it repeatedly, there's a good chance you'll break a strand. Even so, I've broken strands before and gone hundreds of miles.

Look over your cable, housing, and routing very closely. You want as straight a pull as possible, with no rubbing or burrs. The answer is there, you just need to see it.

 

Always have some tension on the cable. Don't run it slack in small-ring small-cog.

 

I had the same problem. I learned from the Joe at BikeCo that that model had a bit of a design flaw in the cable angle. The cable breaks often if you continually hunt for a lower gear than the lowest - in other words, assuming it's not rapid rise, the more you push your thumb on the lever when you are already in the easiest gear, the more likely you are to break the cable. That's what I was doing. Shimano fixed this problem on the subsequent years, but it's still a good idea to know what gear you are in instead of continually pushing the lever to make sure you are in the easiest gear.

 

take the bolt and clamp off and grab a file. look for burs, and smooth the edges. thatll help.

 

In addition, maybe look into using Powercordz instead of the conventional steel cable. Not cheap though.

 

I've seen that before...but only when I've released and reset the cable in the clamp, multiple times trying to tune the rear derailleur. Eventually, you just have to bite the bullet and buy new cable.

 

Thanks everyone for your input, got some useful tips! I'm going to check out that bolt make sure its smooth and then clamp the new cable down only once! I can definitely say a few of those breakages would be from multiple clamps while tuning, hopefully this new one will work for me.

 

I had this same derailleur and had the exact same problems you are having. I tried everything and noticed the cable angle being off liie herz said above. got a new derailleur recently and havent had the problem since. I also compared the cable angles on both derailleurs and the new one looks better with no sharp shoulder for the cable to rest on

 

Also make sure you are not over-tightening the bolt. The tighter you make it the more the cable gets pinched and the more likely the individual threads will break.

 

also, buy good cable. coated stainless shimano and jagwire seem to break less. generic zinc coated is crap.

 

I have the same unit, and notice when you cycle thru the cog back and forth while only watching the cable it answers the question itself why they break. I changed my first cable weeks after the bike was new, the 2nd one lasted a year. Still good now but I'm changing out my shifter to gripshift and was thinking I might as well get a no hastle derailleur why I'm at it.

(Nailknot) Suggested the correct Sram attack 9-sp-shifter. Can I get some suggestions on a different unit. Don't care about weight, just a trouble free Shimano 9-sp derailleur. No frills. (Any one see the 899.99 electronic one? Jeeeezz).

Thanks