sirtirithon

I am having a very annoying chain rub issue on my new Salsa Fargo. It has a Sram X7 front derailleur and this is a 2x10 system. A few days after buying the bike the chain started to rub in on the biggest ring up front, smallest in back and vise versa. I knew it was probably the new cables breaking in, so I adjusted the barrel tensioner and it went away.

Then it started again, so I took it in for the free tune up since I had a couple hundred miles on the bike already. Left and it was perfect. Then it started to rub again, so I took it back to the shop. They reinstalled the front derailleur and tuned it again, and it left shifting perfectly and no rub. Then it started again a few days later, I was on a ride near the bike shop so the mechanic tuned it up again.

Well, today it is now rubbing again. So I adjusted the tensioner to clear the chain but it only lasted 10 miles and its rubbing again. I'm going to call the shop again but I'm getting pretty irritated. It's a big pain to take the bike in because I don't live very close. Also, I'm not blaming the mechanics. They tune it great it just refuses to stay tuned. I have 350+ miles on the bike the cables should be broke in by now. I'm tempted to just eat it and upgrade the derailleur but to what??? I want something I don't have to fiddle with everyday. Any advice on what to do? Is this something I should ask the bike shop to replace/upgrade free of cost? I mean I have owned the bike for a month and this derailleur has given me a headache since the first week. Thanks!

dsbrantjr

It sounds like something is creeping out of adjustment; 10 miles is not enough for the cable to stretch. Possible the cable anchor bolt or derailleur mounting is not tight and is working loose. More likely a cable housing end is not correctly prepared and is working its way into its ferrule or cable stop. I'd inspect the housing ends to be certain that they are cut square, filed flat and do not have any stray wires sticking out, and that they have the proper ferrules installed. If there is a cable guide under the bottom bracket make sure the cable is properly routed.

gyozadude

+1 on the housing ends. I was working on a bike recently with SRAM front and the same issue. The mechanics were using the wrong cable housing caps for the derailleurs. The caps were too small. To get them to fit, they stripped off a little bit of the plastic housing to expose the compression-less wires, then slipped the cap over that. And if I rotated the cap a little and re-installed the housing as is, there would be no chain rub... but barely and only if the FD were perfectly adjusted. From the outside, I couldn't tell at first. But after removing the housing and pulling the caps off, I found they did this intentionally (because it was on both ends). I trimmed the ends of the housing, replaced with new caps that fit and no more rubbing. And the FD has at least a couple more of side travel for the same cable pull from smallest chainring to biggest.

sirtirithon

Thanks for the advice guys! I talked with the shop and that is what they are thinking as well now, cable housing issues. They also said it doesn't help that I have a FSA Comet crankset (iffy performance!). I am going to upgrade to a XT crankset and have the housing replaced and continue running the X7 derailleur and see if that cures the problem.

dave35

The solution to chain rub issues: get a friction shifter for the front derailleur. This upgrade (whether it's a Thumbie with an old downtube shifter or a crappy Falcon unit) will cost you several hundred dollars less than your proposed upgrade path.