Please help me figure out what's going on with my rear derailleur!

[NorvernRob]

Afternoon all

I really hope someone can come up with an answer to this as it's driving me mad.

I can setup my Sram Red rear derailleur perfectly from scratch, and it's silent in every gear. However, 30,40,50 miles or whatever later it's noisy again as though it's out of alignment. I can improve it by tweaking the cable tension but can never get it quiet in all gears unless I release the cable and start again.

I've looked at the manual and youtube and everything is setup exactly as it should be as far as I can see.

I'm at a complete loss as to why it's happening, unless there is something wrong with the cable routing somewhere and something is pulling the derailleur out of line. It's not chain rub btw, it can be noisy in just a couple of gears or several. The cable is clamped tightly so it shouldn't be moving.

I got the bike brand new in the box so it's cabled as per the factory build.

Any ideas welcomed! I'm at the point where I'm going to buy new cables and outers and recable the thing even though it's only done less than 1k miles.

I'll post some photos if it would help.

Thanks in advance!

Rob

 

[Ian H]

It could be something very simple such as a missing ferrule on the outer.

 

[PaulSecteur]

When you say you can fix it by tweaking the cable tension, does that fix it for both going up and down the gears?

I have never had it on a new bike, but it sounds like the inner cable is binding somehow with the outer, either from being dirty (unlikely on a new bike) or being defective.

I would remover the inner and have a look at their condition and make sure they are not frayed and also make sure they feel the same along their length (Watch out for sharp bits!)

Failing that, new inners and outers to eliminate the cables.

 

[NorvernRob]

Thanks for the replies!

Photo time, should there be a ferrule where the cable exits the frame?





There is everywhere else..

 

[Pikey]

I had something similar, then my shifter jammed during an audax, check the cable hasn't frayed inside the shifter.
I wish I had.

 

[PaulSecteur]

should there be a ferrule where the cable exits the frame?

I haven't done an internally routed frame so Im only guessing, but it looks like the cable stop is inside the hole in the frame. I would expect there to be a ferule on both ends of that section.

 

[John the Monkey]

I haven't done an internally routed frame so Im only guessing, but it looks like the cable stop is inside the hole in the frame. I would expect there to be a ferule on both ends of that section.

Check the techdocs - it seems, increasingly, to be the fashion for the outers to butt directly against the point of entry to frame, or component.

I spent several frustrating minutes fitting R600 brakes to the Giant, trying to get the ferrules to fit into the cable adjusters on the brakes. The tech docs do point out that the ferrule is "integral" on these brakes, so the outer doesn't need one.

 

[TheJDog]

That looks like it should have a ferrule, but definitely check the docs for the frame. If all you're doing is undoing and redoing the cable clamp, that is nothing that shouldn't be fixable with the barrel adjuster - unless your cable is loosening so much that you don't have the range in the barrel. Which suggests that the outer is not right somewhere. Loosen the cable, and take the end of that bit of outer out of the frame to see what it looks like. If it looks squashed you're probably missing a ferrule. I am probably teaching your granny how to suck eggs here.

 

[Dragonwight]

Have you checked the cassette is secure and there is no movement in it.

 

[NorvernRob]

That looks like it should have a ferrule, but definitely check the docs for the frame. If all you're doing is undoing and redoing the cable clamp, that is nothing that shouldn't be fixable with the barrel adjuster - unless your cable is loosening so much that you don't have the range in the barrel. Which suggests that the outer is not right somewhere. Loosen the cable, and take the end of that bit of outer out of the frame to see what it looks like. If it looks squashed you're probably missing a ferrule. I am probably teaching your granny how to suck eggs here.

That's the strange thing, I can adjust the tension with the barrel adjuster until it's way too tight and skips gears, and I can loosen it enough for the chain to not make it up onto the top cog. But no amount of fine adjustment will get it quiet again apart from in some gears.

I understand exactly what you're saying, it doesn't really make a lot of sense, which is why it's got me scratching my head. I was convinced the derailleur was bent or something, but when I set it up from scratch and set the limit screws etc it was perfect - for about 40 miles! I haven't actually checked the cable outer, I'll have a look in a while.

Have you checked the cassette is secure and there is no movement in it.

Yes, I fitted the cassette myself as the original wasn't what I wanted.

 

[NorvernRob]

Had a look, the outer does have a ferrule on it inside the frame and everything looks as it should be. I've reset it up again with the cable clamp off and it's running perfectly so will see what happens now.

 

[Dragonwight]

I mention it because I had a similar problem, I also had changed the cassette and even though it was supposed to be compatible there was a small amount of movement that appeared after riding it which meant i was re indexing it after every ride. I ended up using a spacer to fix it. P.S have you tried putting the original back on?

 

[NorvernRob]

I mention it because I had a similar problem, I also had changed the cassette and even though it was supposed to be compatible there was a small amount of movement that appeared after riding it which meant i was re indexing it after every ride. I ended up using a spacer to fix it. P.S have you tried putting the original back on?

You've got me wondering a bit now. It came with full Sram Red apart from a Dura Ace chain and cassette (standard Foil setup) I sold the cassette and replaced it with an Ultegra one, which as far as I could ascertain was pretty much the same barring 40grams or so extra weight due to different material. I never rode it with the Dura Ace cassette so I've no idea if it would have done the same thing.

I think at the very least I'll have the wheel off, check the cassette for any play and remove/refit it. I'd be a bit miffed if I shelled out £100 on a Dura Ace cassette and it didn't fix it though!

 

[400bhp]

Have you got the (any?) correct spacer on the freehub?

Is the rear hangar straight?

I have a similar issue to you albeit it takes a bit longer to go out of true. I suspect it's either/or the above (I have Planet X AL57 wheels on and if I run the bike with a Shimano R501 wheel I don't have the problem as bad).

For me the issue isn't bad enough to worry about.

 

[NorvernRob]

Have you got the (any?) correct spacer on the freehub?

Is the rear hangar straight?

I have a similar issue to you albeit it takes a bit longer to go out of true. I suspect it's either/or the above (I have Planet X AL57 wheels on and if I run the bike with a Shimano R501 wheel I don't have the problem as bad).

For me the issue isn't bad enough to worry about.

The Ultegra cassette came with an identical spacer to the DA one, it fits into a recess in the rear of the cassette to give a flush fit. So not really a spacer per se.

If the rear hanger isn't straight then it never was as I got the bike brand new sealed in the box. The derailleur looks dead straight now, no doubt it will ride perfect for a while so if the hanger was bent surely it would always be noisy?