Rear derailleur cable hanging up

[OakLeaf]

12 miles from home today, my rear derailleur decided it only wanted to be in the two lowest gears. :mad:

Once I got home and took a look at it, it appears the cable is hanging up either in the top housing along the handlebars and frame, or in the brifter itself. It seems to be moving freely everywhere else.

I'd recently put on a stem with a steeper angle, and I wasn't completely in love with it, so I went back to the shallower one I had on, in case the housing was marginally too short. (It was shifting fine right after I put the stem on, fwiw.) After doing that, lubing the cable at the housing near the derailleur and under the bottom bracket, and just generally yanking on it here and there, it's shifting some, but not very well, and it's really reluctant to go into the highest gear.

I seem to recall someone saying that the cables should NOT be lubed at the brifter because of the risk of light lube/solvent getting into the grease in the brifter. Is this correct?

Is this just a sign that the cable needs to be replaced? They're almost two years old but there's no visible sign of wear; I don't want to bother if it isn't going to help. What about replacing the housings (grrr... PITA... :p)

Any other thoughts?

[lunacycles]

When you say the two lowest gears, are you referring to the two largest (rear) cogs or the two smallest cogs? If the latter, there is a good chance your cable just came loose, and needs to be tightened again at the derailleur, and then everything re-adjusted. If the former, then you definitely have some bizarre binding going on, and if corrosion is not the obvious culprit, pictures would tell the story.

It's not a problem lubing the cable at the brifter, but how do you do it? The housing goes right into the brifter, and the cable is inside of it. You can shoot a little in (assuming Shimano) on the outside of the brifter where the head of the cable sits, but it won't do much. But regardless of where you lubed it, unless it is gunked up galore, it shouldn't be a problem.

The short housing could be an issue if it is obviously kinked.

If you do lube the cables, you should do so only where they are bare and right where they enter or exit housing. At the front end, you should down shift til the chain is in the smallest cog, and then lube the cable (about an inch worth) where it exits the housing at the cable stop on the downtube (or head tube). Shift all the way to the biggest rear cog, and then lube the bare cable (again, an inch or so) where it exits the housing at the cable stop on the chainstay. Also, wipe off the cable lightly after you lube it.

The point of lubing the cable is to keep it moving smoothly in those areas where it encounters friction: that means where it enters or exits cable housing.

[OakLeaf]

It was the two largest cogs, and as I said, after I messed with it some, it will shift into all but the smallest cog, but not smoothly. It's definitely hanging up and definitely not the adjustment. No obvious kinks, no visible corrosion, nothing unusual-looking to take a picture of. Nothing that looks the slightest bit different from the way it looked two weeks ago when everything was fine. It's just hanging up inside somewhere.

I'll try the procedure you recommended for lubing the end of the cable on the down tube - but I really think the problem is "north" of there. As I said, nothing visible.

[aicabsolut]

When the cable starts to die, it will more likely not really stay in any cog easily or it will tend to LOSE tension, meaning that it will want to stay in the smallest rear cogs. But even if the cable is still ok, the housing might not be.

It sounds to me more like the shifter is starting to go and needs to be flushed (high pressure water and WD-40 can work, but relube after). Does it feel different to shift?

[lunacycles]

I didn't mean to imply you weren't doing enough. I only got from your post enough to reply the way I did. Sorry to imply otherwise, if I did.

If you want to know if it is the cable, then completely disengage it from the rear derailleur, pull the housing out of their respective stops, and slide the house along the cable to find where it is binding. Lube it as much as you can along all sections where it sits inside the h ousing and then wipe it down before reattaching it at the rear derailleur. You will have to readjust the cable tension if you decide to do this.

Check both ends of each piece of housing, especially where the ferrules are, and double check that there are no sharp bends or kinking that could be binding the cable, especially the piece coming from the brifter that you suggested is too short. I know you said you did this, I am just trying to cover all bases.

It sounds like corrosion to me, except corrosion is more common "south" than "north." It could be binding. It could also be your rear derailleur hanging up (lube it at all pivots just to cover that base), but it doesn't sound like it from what you are saying. Honestly, it could be a lot of things, but I am just trying to lend a hand via a forum where I can't see the bike.

[OakLeaf]

Margo, I didn't mean to sound snippy, I'm just frustrated. They're R700 brifters, for reference.

The inner workings of brifters are a mystery to me. I've looked at the exploded diagrams and the service manual, and they're still a mystery. :rolleyes: My expertise in bicycles goes back to friction shifters and ball bearings. :eek: Lately I'm more comfortable with throttle and clutch cables (and if those are hanging up, it can kill you :eek:). Generally I'm reasonably mechanically minded if I can get my hands on something, but I'm such an abstract thinker that it's pretty difficult for me to look at a diagram and translate that into reality. If I don't have an experienced mechanic to show me something for the first time, it's almost comical how many times I'll have to look back and forth from the service manual... to the real thing... to the service manual... to the real thing... :rolleyes::o

Anyway.

Aicabsolut, YES, my initial feeling was that it was the brifter itself. When I try to upshift, if it doesn't "take," it doesn't click at all (not like it was out of adjustment), and if it does click and try to shift it's very soft feeling. Downshifting feels fine.

Could you explain more? When you say it's "starting to go," do you mean that it's going to need to be replaced and flushing it is just a temporary fix? If so, is there any way to estimate how much more service I'd get out of it if I did that? There aren't even 5000 miles on them - although half of those are in Florida, which of course is very hard on anything metal and anything moving - if it's metal and moving, fuhgeddaboudit. :( But, to the best of what I've been able to see without disassembly, the hoods have done their job, and there was neither sand nor salt inside the brifters when I replaced the brake cable housing and swapped my handlebars out recently.

I WAS careful and very clean doing that, but there's always the possibility that I scr*wed something up in one of those procedures. :rolleyes: The shifting problem didn't start immediately afterward, though. (For reference, I replaced the brake cable housing because it was too short with the new stem, not because of any sign of age or wear. It appeared to be in fine condition, no external cracks, no sign of internal corrosion, the brake cable moved freely through it. But as far as the length of the derailleur cable housing is concerned, as I said, I put the old stem back on yesterday, and there were probably 2500 problem free miles with that stem and those cable housings.)

If I were to flush it, how exactly is that carried out? Does the brifter have to come off the handlebars? Is it possible to take the brifter off its bracket (so that the bracket, and more importantly the tape, doesn't need to come off the bars) without it being more trouble than it's worth to re-install it (or a new one)?

How much disassembly needs to happen? Is it going to be much easier with Shimano's return spring installation tool, or does that not have to come apart, or is there a "regular" tool or something around the garage that can substitute for the special tool? When I re-lube, do I have to be sure that all traces of solvent/WD40 are removed first? What type of grease do I use, and where does it go?

I can see that this is the sort of thing that it's probably cheaper to replace than to pay the LBS for labor to service it (plus I'd rather not be without my bike for a week or more waiting for them), but if I can service it, and if I can gain a reasonable amount of useful life out of the brifter by doing so, I'd like to try.

THANKS!!! :)

[aicabsolut]

Yes, I do mean that the shifter could be near the end of its life such that it would need to be replaced. The thing about Shimano shifters is that they are pretty much not serviceable (not rebuildable). Don't take it to the shop unless it's a last resort, meaning you've worked on it and you've also replaced the cables and housing. Basically, if the shop works on the shifter and breaks it, you are out of luck, because they aren't really supposed to do any disassembly. It's as risky as doing it yourself. New shifters are expensive (but you may be able to find just the one you need somewhere like eBay).

BUT, you can do a lot of good servicing yourself by flushing out all the gunk. The salty air where you are isn't great for them for sure, but I would definitely try to rehab the shifter before you give up.

It's unlikely you're going to get it off without undoing your tape, because the screw and bracket is covered by tape, and the bracket doesn't really loosen enough (at least on 31.8 bars) to slide off over tape. You can do a lot of work without removing it, though. I had to remove one of mine when the knobby end of the cable got stuck in there this fall after the cable snapped (that was tricky and involved 2 of us going at it with tweezers!) but I was able to do a lot of work with the brifter on the bike.

Just compress the brake lever to expose as much of the innards as possible and flush really well with copious amounts of WD-40 (using high pressure water can also work to get you started, depending on what's up there). I mean DRIPPING with WD-40 sprayed in there at close range. Then move the levers all around and get at any spaces with the spray. From what you said, I'd pay special attention to lubing things up when the inner lever is moved. You might want to take a flashlight and look at the dirt and grime that's up in there when you do this. Sometimes, I also use a Q-tip to get the gunk out of the bigger areas under the shifter.

Wipe down the levers well afterwards with water (they will be slippery with WD40 the next time you ride!), and when everything is dry, relube the shifter with something. You might have to relube a few times over the next several rides.

I doubt you did anything to the shifters when you moved stuff around. It'd be more likely that you damaged the cables then. It's probably just bad timing.

Even though it looked clean then, it could be dry and/or gunky up in there now. My shifters have gotten kind of sticky and unresponsive feeling from time to time. I've only really flushed them once, but I've used a thin cleaning lube (Prolink maybe... maybe not the best, but it's what I had) a few times with good results. Flushing them with WD-40 was a lot better.

It might not be a bad idea to investigate the cable more too. Taking the cables out of the shifter will allow you to move it more freely to clean it. Then you can look to be sure the cables aren't starting to fray or something near the end. This is where you'll run into bartape problems, though.

[lunacycles]

My hunch is, that if you aren't getting satisfying clicks with the brifter when downshifting, it is probably the brifter. As aicabsolut said, they aren't really serviceable. If her method described is deemed futile, you can often find a used version of the brifter (just a single one) on e-bay, although I would imagine the R700's are more hard to find than other models.

You can also completely disengage the brifter from the handlebar without too much hassle by completely undoing the 5mm allen bolt on the outside of the brifter beneath the hood, even without removing tape...it is getting it re-engaged that I find to be a true p. in the a.

[OakLeaf]

I ran it by the boys at the LBS and they said the same thing. Knowing it's near the end of its life, I don't want to push it and risk having it give up the ghost completely when I really want to be able to ride. They quoted me a very reasonable price (considering) for a new set installed with new cables and housings, so I went ahead and ordered them. Then I can tinker with the old one with no time pressure, and if I'm lucky, have a rebuilt spare for when the new one goes (although hopefully it'll last me longer than 5,000 miles!!! :mad:)

I ran some WD-40 through it tonight to hopefully get me through the next few days until the new ones come in - the LBS recommended some other solvent they have (I forget what it was called) but WD seemed good enough for now.

I don't have enough experience with the LBS to know how much I should trust them, and one of the guys I ride with doesn't have a super high opinion of them, so it made me feel a lot more confident to hear them say the same things you did. Thanks!!!

[aicabsolut]

I've heard of some people having great success flushing out the brifters such that the brifters now have more life on them post-service than they did before they started getting stuck. It can really bring one back from the dead. But you never know for sure how long it'll last.

I think that in your climate (I'm from coastal Georgia, so I know how different my bike parts behave when I take it back home), you might want to take extra care with the brifters in the future when you clean your bike. Maybe give them some extra lube or WD-40 and lube every few months and when you wash your bike (which you probably do more often than those without all that salt and sand), be sure to rinse out the brifters as well as you do the drivetrain. It might help your next set last longer, though it could be that your current one dying is just bad luck.