How often do you replace your rear derailleur cables/housing?
Thanks to this board, earlier in May 2010, I was able to figure out what the problem was with my rear derailleur (at this thread) and I replaced the cable and housing and everything worked well for a while.
It's more or less six months later. I've been riding almost every other day or at least once a week since that point. It occurred to me recently that new bikes are usually returned to the store for a free mini-tune up after a few weeks of riding, so I figured my shifting problems were due to a stretched cable. So I tightened it up and things sort of worked again for a while.
Anyway, today, finally, I was trying to get rid of the problematic shifting. I have to double shift to get from the 3rd cog to the 4th cog/5th cog. That's the biggest problem. After messing around with the limit and B screws and barrel adjusters for a while, I finally got the chain to shift from 1 through 7 perfectly, for the first time in months. (By the way, my bike shifts differently when I'm actually riding, which I just read on these boards may be caused by some other problem?)
The downside to this perfect 1–7 shifting was that I could not shift *back* from 7 to 6 or 6 to 5, in single steps. I had to crunch shift all the way back to lowest gear. I almost settled for this, lol, that's how tired i was of messing around.
Anyway, then I got to thinking, maybe it's just time for a new cable and housing? So... instead of asking WHAT the problem on my bike is, because it's probably nothing new, I was curious as to how often a rear derailleur cable should be changed out.
The lifespan of cable and housing is highly dependent on the conditions I ride in. If things are really sloppy, the life of my cable housing is measured in weeks not months.
Full length housing, sealed ferrules, nosed ferrules with shield, and other things can help prolong the life of cable housing in bad conditions. And of course, even in good conditions, it does not last forever. It's hard to put any number on it, but "a few months" sounds about right.
The stuff is cheap enough so it's not hard to justify replacing it often.
If cable / housing is not the problem, derailleur hanger alignment is the next thing to check.
"derailleur hanger alignment"
Hmm. Good suggestion, I'll run out and check that while I still have some daylight.
I had something similar on an old bike, and it turned out to be burrs on the ends of the cables where they went into the ferrules. If the cable is cut improperly, it can leave a burr that will grab/rub the cable and can cause very inconsistent shifting.
You should be able to pull the ferrule off easily and look into the end of the cable. If there are burrs or the end of the cable housing bends in, take a dremel and cut it off flush. Wire cutters, diagonal cutters, etc can easily leave that burr.
Just one more thing to consider and eliminate.
Regarding the hanger, everything is in excellent condition, straight and not bent. I just tuned the rear and front derailleurs using the SFMTNS videos on YouTube and the front derailleur works better than before.
Out of curiosity, I slid the housing up both cables and the front derailleur cable is essentially a rope of rust. Considering it probably hasn't ever been changed since I bought the bike, it makes sense.
MightyDingus, you make a fair point. I never did have the proper tools to cut the cables. So in fact, my rear derailleur, when I switched out the cables and housing last spring, were probably done just a touch sloppily (I knew i had the wrong tools but I was sooo careful to do everything as properly as possible with my Leatherman). But now it's undoubtedly come back to haunt me.
I think if I switched out both derailleurs' cables and housings, I'd be a happy man. I just need to get some tools.
Go for stainless cables next time too.
Originally Posted by cinderscopia
Originally Posted by cinderscopia
How was this checked? If just checking by eye, it can appear straight, but looks can be very deceiving. To properly check the derailleur hanger, the Park Tool DAG-1 is required.
Have you measured the chain wear and checked for worn chain? Unless you smash them derailleurs and the cables last a long time. If you're having shifting problems, it likely means the chain has worn and worn down the cogs.
Originally Posted by cinderscopia
If you want your drive train to last, buy inexpensive chains, a chain wear gauge and replace the chain when it starts to show any wear. Once the chain wears "or stretches", it starts wearing the cogs and you pretty much need to replace both to get shifting working again.
If it's been 6 months and you've been riding much at all, you should have replaced the chain at least once. If you're riding in conditions that would gunk up a derailleur cable in that time, I'd guess you'd go through at least 2 chains.
- Booker C. Bense
I don't have a schedule for cable replacement, except that if they get a bit funky in the late fall or early winter, I try to keep them until March so the new ones don't get aged quickly by road salt.
I have a quick diagnostic for cable friction, which I use as a guide for replacement. Usually the first problem will be sluggish upshifting when the RD return spring can't overcome cable friction.
I confirm the cause by plucking the bare wire at the downtube like a guitar string. If that pulls down a bit more wire and corrects trim, it's time to re-lube or replace the housing. In my experience the rear always goes first, and depending on my mood, I'll either replace both cables, or try to skate by on the front until next time.
Obviously, if a wire frays, it gets replaced. And whenever I replace wires, I replace the housing at the same time.
The key to solving any problem is to understand and address the underlying cause.
I'd say 6 months is a good run if you are riding offroad and in occasional mucky conditions.
Sometimes I don't even get 6 months, sometimes I can go longer.....but I usually change my stuff out every 3 or so months. Oh the joys of working in a shop....= )
I would mark your housing runs with a tab of masking tape, and number them for later referance.
Bring your old housing into the shop with you, and let them know you need to buy some housing and cables.
Then nicely ask if they wouldn't mind cutting the new housing to match the ones you brought in.
It shouldn't be that big of a deal for them, as it's only like 4-6 cuts.
Be sure to buy new ferrules with the new housing, and if they have the option, buy the stainless cables.
Stay away from the galvanized/basic cables as they won't last for $hit.
It may be a good idea to just buy yourself a set of cable cutters, now that you realise you will be using them a few times a year.
If you can't spring for it, do as I suggested previous.
When you get home, match up the correct length pieces with the ones you marked and numbered and you'll be good to go.
Look, whatever happens, don't fight the mountain.
Nice ends on the housings are important. If the shop doesn't use a bench grinder or something on them, do it yourself. A hand file works too, but it's annoying.
With the rear housing section, if it's a very short loop and makes that 180 turn older-style and road derailleurs require, hold it bend when you touch up the ends. Can be a bit of a pain with a hand file, but c'est la vie.
Finally, I'm with the poster who says check on your chain - my experience is that shifting problems that only show up on my favorite cogs are a worn chain or cassette.
"Don't buy upgrades; ride up grades." -Eddy Merckx