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Changing chain and Derailleurs

2K views 28 replies 6 participants last post by  sinfony78 
#1 ·
What order should I change and do adjustments to them in when changing all at one time?
 
#4 ·
They really have minimal effect on each other.

However, before considering replacing a derailleur, I'd start by looking at the cheap parts that can really screw up shifting. It doesn't matter how expensive your derailleurs are if your chain is nasty or worn out or your cable housings suck. Front shifting is also heavily influenced by quality and condition of the chain rings. And the shifters are the brains of the operation, so if they're messed up, they'll mess up the whole thing.
 
#5 ·
some background. bike is 2005. rear cassette and chain changed last year. shifters changed 2 weeks ago to shimano slx (left had crapped out). have had front derailleur issues for a while. going to upgrade rear just because i can but have no issues with rear shifting. New cables and housing with shifters. read about all the different types of chains on park tools so i want to get the same chain bike came with, i don't know what it was changed into last year.
 
#7 ·
Could be anything from just bad adjustment to everything being worn out. You need to take a systematic approach to identifying what is worn and what is just poorly adjusted. Front derailleurs tend to last almost forever so I would hedge my bets that it is some combo of worn chainrings and adjustments.

Keep in mind that depending on how much you ride, chains and cables often need replacing more than once per year. That is why it's better to look at maintenance intervals in terms of miles or time ridden and not in terms of absolute time
 
#10 ·
i've checked my adjustments myself several times; had it serviced at REI earlier this year (prior to getting back into biking), and had shifters changed by another LBS...on the stand, it shifts fine, when i'm on it, it is does not shift consistently...sometimes it will be fine, other times it has problems going to smallest chainring, on some trails with lots of roots, the chain will jump off the rings...it's a pretty new development that this started happening

so here's the timeline:
- end of last year, beginning of this year (about 50 miles no bike since then), changed chain and cassette - done myself
- REI - serviced bike (silver tune)
- 1 month ago - changed all 3 chainrings (they were obviously warped)
- 3 weeks ago - changed shifters (front shifter stopped working)
- on trails, shifting in front still not consistent - followed adjustment procedures on parktools and youtube (i think from bikeradar.com), works fine at times, especially on pavement; once on grass/trails, does not shift well again

so everything's been switched out other than the derailleur, so that just tells me that's the problem
 
#11 ·
not necessarily. It could still be something else that we can't pin point because the bike is not in front of us, and there could be a detail that we aren't getting. For instance, when the shifters were changed, was the housing changed as well? Was the chain changed? ( not sure if you said that or not). It could be a compatibility issue as well, where the new chainrings aren't the right chainring for your cranks, chain, gearing etc.

If I were you, I'd bring the bike to another shop. Tell them what is going on shifting wise, and then let them actually fix it. I almost guarantee that there is something going on with atleast one of the possible things I said above.
 
#12 ·
i bought a raceface chainring set, same number of teeth as was stock (44/32/22)...and chain was changed less than 50 miles ago

so here are some observatinos after doing some adjustments today

- bikeradar.com's youtube video says to make sure the mech height is 2-3 mm above the teeth...parktool.com's website says 1-2 mm...i went with the shorter measurement this time
- in order for the bike to shift somewhat back to normal, i had to misalign the mech with the teeth...if it is straight on, it won't shift to smallest chainring
- on middle chainring, there is some rubbing of the chain on the mech when on the most extreme cogs on the cassette, but not too bad...on bikeradar.com's video, this should be fixed with barrel adjustments...if i fix this, it will cause rubbing on largest chainring

so right now, i can't get perfect adjustments, i have to get the best adjustment possible

going to a derailleur adjustment class at the LBS tomorrow...hopefully they can use my bike as an example
 
#17 ·
I have always preferred the Park tool guideline of 1-2mm from the teeth. that's more similar to the mfr recommendation sticker that comes on a new derailleur and it works well when done right. IME, it is super rare to get your drivetrain set up so there's no chain rub on all gears in the middle ring. you really shouldn't be shifting your chain to extreme angles, anyway. if you are at the bottom of your cassette, you need to be in the big ring. middle of the cassette, middle ring, top of the cassette, small ring.

what do you mean by "misalign"? in the front, the derailleur cage kinda has to go past the ring you want to go to a little bit just to make the chain move how you want. going to a bigger ring, you can give a little extra push on the shifter to do that, but going to a smaller ring needs just the right adjustment. if you mean you had to rotate the derailleur so the cage isn't parallel to the rings, then something is off.
 
#13 ·
I like the Park Tool repair instructions better. Nice pictures and I can read them at whatever pace I want to.

Also, if you didn't finish the ends of shift cables yourself, you can't assume it was done correctly.

One of my teachers several years ago had a funny comment about one of the sound designers, who'd been entrusted with making our haunted house sound spooky with the cheap and chewed equipment the school had. He said the guy had done too good a job with it, and we'd never be able to get a donor to give up some nicer stuff.

On bikes, if there's not actually play you can feel in the derailleurs, the shifter housings are a really key spot to get good performance. But it takes an extra step to do it really right.
Cables

The other thing that's really important is your ongoing maintenance habits. I try to wipe my chain after every ride, relube as needed, and pay attention to things that aren't functioning as well as they could. When you ride bikes off-road, things just change too quickly, get too dirty, get hit too often, etc. to take your bike to the shop every couple months and think you're maintaining it. It's not like I spend a ton of time on any of this stuff, in general - the extra wipe only takes a minute or so, including hitting my fork stanchions while I'm at it, a lot of the minor adjustment is stuff I do without even stopping during a ride, and the big stuff was probably going to require a shop trip in the near future.
 
#14 ·
just because it shifts fine on the stand doesn't mean it will shift fine on the ground with weight on it. also, when you get stuff done like the shifters (shifters usually come with inner cables, so your cables are probably only 3wks old, too), you have to get adjustments done as those cables break in, or "stretch" (it's not really stretching, but the effect is more or less the same). and oftentimes, what appears to work fine on the stand is still slightly out of adjustment and will require further tweaking when someone is on the bike.

When I do work on my bike, I get it working the best I can on the stand, then take it for a spin where I make more adjustments with the barrel adjusters at the shifter end while I ride to get it just right. and oftentimes, it will try to ghost shift when I get to the first steep hill on the trail and I will tweak it again and finally it will be good.

the information you have given us does not suggest that anything needs replacing. chains occasionally jump off chainrings in rough stuff if you don't have a chainguide, but there's just not much you can do on a 3x system. SRAM drivetrains and the new Shimano stuff with the roller clutch drop chains less, but that's an expensive swap for a small problem. it's possible your chain is too long, but without seeing it, I can't say. you will have to check a guide regarding choosing chain length.

I still think you can solve this without spending money on it. if you still want to buy new parts "just because" there's nothing wrong with that, but until you get your issues worked out, new parts won't fix your issues.
 
#16 ·
ok i haven't given thought to cable stretch...it's a deore lx, whatever is stock on i believe a 2004 or 2005 gary fisher tassajara...and i got shimano SLX shifters installed

so to account for cable stretch, would barrel adjustment fix the problem, or should i go through the whole derailleur adjustment again?

natehawk, what do u mean by ghost shifting

i'll stick with this for a couple more rides and see if i can pinpoint the problem
 
#20 ·
ghost shifting = chain skips around and shifts on its own because it is out of alignment.

usually, barrel adjusters are enough to address cable stretch unless you've let it go for too long and the barrel adjusters cannot take up enough slack in the cables.
 
#19 ·
yes, misaligned means cage is not parallel...if it is parallel, it won't shift to smallest chainring...i just reached that conclusion today

however, it has shifted better after making this adjustment while on and off the bike than it has in the past

also as i follow the cage and measuring 1 mm to the teeth, i notice that the cage does not follow the chainring perfectly, so it is 1 mm at the top and the gap increases towards the back
 
#23 ·
why won't it get to the smallest ring if adjusted parallel? I agree with Andrw that if you get this figured out, it will probably solve your trouble. I'd like more details on these Race Face rings you put on it. which ones did you install? you have to be careful about this stuff because there's 11spd, 10spd, 9spd, and even some 8spd parts on the market and the interchangeability is not all straightforward.

yes, the gap between the top of the teeth gets bigger as you move to a smaller ring. It's supposed to do that, which is why it's better, IMO, to have a smaller gap at the big ring.
 
#22 ·
Front derailleurs are often shaped to continue working okay with the largest sizes of chainrings that show up on mountain bikes and MTB-like objects. For example, a hybrid (or MTB for a beast-man from the '80s) with a 48t large ring.
 
#26 · (Edited)
specs on the drivetrain:

Front derailleur . . . Shimano Deore Top pull, 34.9 mm/ 1 3/8" attachment
Rear derailleur . . . . Shimano Deore LX SGS
Crankset . . . . . . . . . Bontrager Select 44/32/22 64/106mm bolt hole circle
Bottom bracket . . . . TruVativ Giga-Pipe 73 x 113 (shell x axle,mm), ISIS splined axle
Chain. . . . . . . . . . . . Shimano HG-73 9 speed, 106 links
Cassette. . . . . . . . . . SRAM PG950 11-34, 9spd

----------------
the cable loosens when i'm on smallest ring...according to vid, i tighten barrel adjuster all the way, make low limit adjustments, then pull cable taught and tighten...then make further adjustments with barrel once high limit is set

-----------------

appreciate the help guys...getting late and i put the bike away, so hopefully the LBS class will show me a few things

will update tomorrow
 
#27 ·
if the cable is getting loose at the small chainring, then the derailleur is reaching some kind of lower limit. it's either the limit screw (you're sure you have been adjusting the right one?), some debris in there is preventing the derailleur from moving, or the derailleur really is at its minimum and there's some other problem like with your chainline like Andrw mentioned.

With your crankset/bb combo, your chainline would be affected by how your bb is threaded into your bb shell (is it centered, off to the left a few mm, or off to the right a few mm?) and your bb spindle length. In your case, check to make sure your bb is not off-center a few mm to the non-drive side of the bike.
 
#29 ·
i guess i meant the cable in general is slack while on the small chainring, which is how it's supposed to be, right? i'm checking the tension under the top tube..however, it is still bolted down to the derailleur pretty well

as far as crankset/bb combo, i've made no changes down there...i'll ask the shop today what they think

and this is the race face chainring set i bought -
Tree Fort Bikes - Online Bicycle Parts and Accessories, Bicycle Tools and Maintenance
 
#28 ·
Deore and LX are really nice groups. Certainly things wear out, but I don't think you're going to do better replacing those derailleurs if they're not actually worn out. Incidentally, while I have the SLX front derailleur, I've just been buying Deore rear derailleurs. I figure that when, not if, I break them, they cost less to replace. My 'cross bike also gets cheap wheels until I actually wear one out rather than damaging them in crashes. :p "Don't race what you can't replace."

Hopefully you learn something good today. If not, I think your best way forward is to figure out what, exactly, is stopping your derailleur cage from returning to a position closer to the centerline of the bike.
 
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