Rear mechs - do the...
 

[Closed] Rear mechs - do they wear out

Posts: 4785
Full Member
Topic starter
 

I've got an XT (10 speed) thats probably 4-5 years old.
The bike (it's on its second bike actually) gets thrashed as much as my skill level allows.

Despite new chain and cassette and chainring and jockey wheels (15-20 rides ago), the shifting is still sometimes a bit off, catching on the next gear, refusing to go down, ghost shifting.
I dont think its the cable, as it seems to run smooth at least some of the time, and behaves perfectly when fiddling at home.

I also drop chains occasionaly despite having a top guide and a relatvely new narrow wide ring. I'm tied to raceface due to cranks sadly, I like the look of the tall toothed sram offerings.

Do mechs get baggy, tired, sloppy whatever? Is it repairable or terminal?

For reference, similar set up, of similar age on my hardtail which sees more miles, far more mud, but far less gnar and due to terrain, probably less shifting per mile; is perfect and buttery smooth in comparison.


 
Posted : 09/04/2021 12:29 pm
Posts: 43882
Full Member
 

Well, they can.... but have you checked hanger alignment?


 
Posted : 09/04/2021 12:30 pm
Posts: 584
Free Member
 

4-5 years?! Yeah time for a new one, they get sloppy and while it may not have bent out of shape on one knock it has probably seen lots of small impacts that bend it out of shape in all directions

The clutch is probably completely knackered as well, those 10 speed ones were never great

Mine usually last about 6 months


 
Posted : 09/04/2021 12:33 pm
Posts: 990
Free Member
 

I had an eagle mech develop play in the parallelogram after ~2 years of use which resulted in poor shifting, so I'd say yes they can. However, none of the other ones I've had ever lasted long enough to develop it before getting smashed off by a rock...


 
Posted : 09/04/2021 12:34 pm
Posts: 21632
Full Member
 

Do rear mechs wear out? To yes, if you look after them. If you don't, they'll normally get destroyed before then.


 
Posted : 09/04/2021 12:37 pm
Posts: 13850
Free Member
 

My XTR 11s sas on its' third bike, had it since 2013 or thereabouts, but let me down for the first time last weekend. Serviced the clutch and got it back to 90% of former glory. Only just took it off to fir 12 speed. Not a bad innings.


 
Posted : 09/04/2021 1:11 pm
Posts: 3642
Free Member
 

Some more than others. But all will get sloppy at the end of that (equal to a piece of string) length of time.

I’ve always dismantled and cleaned the jockey wheels from time to time. Clean and grease the mech if was clogged. Never had one wear out as such before changing bikes. I’m sure someone with even moderate engineering p/mechanical skills could make a basic derailleur last almost indefinitely with regular servicing/replacing jockey wheels etc.


 
Posted : 09/04/2021 1:13 pm
Posts: 45988
Free Member
 

Have you changed jockey wheels?
Have you given it a wobble? (Shimano are usually pretty 'solid' feeling, SRAM have a 'deliberate' wobble from new...)
Is the clutch/tension spring still strong?


 
Posted : 09/04/2021 1:16 pm
Posts: 4785
Full Member
Topic starter
 

Not checked the hanger (dont have the abiltiy to check, but have a spare I can try)

New jockey wheels last summer - fancy hope ones, no play

Serviced the clutch and got it back to 90% of former glory

Is this simple-ish to do, or is it a full garage workshop type endeavour?

Clean and grease the mech if was clogged

Is this dissassembling, or just spraying/lubing the obvious moving parts?

Is the clutch/tension spring still strong?

Notable differnece between clutch on and off, but probably not as strong as others I have seen.


 
Posted : 09/04/2021 1:27 pm
Posts: 13850
Free Member
 

ayjaydoubleyou

Is this simple-ish to do, or is it a full garage workshop type endeavour?

2mm allen key, some brake cleaner, some grease. You don't want drop the little screws and lose them, so don't try doing it on a gravel driveway or a deck with slots in it:) Video below.

Notable differnece between clutch on and off, but probably not as strong as others I have seen.

Sminao clutches are adjustable, so you can make it firmer, video will show that also


 
Posted : 09/04/2021 1:32 pm
Posts: 1609
Full Member
 

GMBN Tech show (youtube) did a recent video on servicing your mech (including clutch) - maybe worth a watch?


 
Posted : 09/04/2021 1:32 pm
Posts: 43882
Full Member
 

Not checked the hanger (dont have the abiltiy to check, but have a spare I can try)

Your spare is just as likely to be bent. A proper tool is one of the best investments you can make.


 
Posted : 09/04/2021 3:49 pm
Posts: 2590
Full Member
 

Ghost shifting, if it is on a full sus, might be that the cable is too short and tension changes as the suspension compresses. You might want to add a little slack in the cable and outer length to sort that out. Also worth looking at B-screw adjustment to ensure enough clearance on the cassette


 
Posted : 09/04/2021 4:14 pm
 Aidy
Posts: 2977
Free Member
 

Mine usually last about 6 months

You have a new mech every 6 months?!


 
Posted : 09/04/2021 4:16 pm
Posts: 0
Free Member
 

If it’s an early 90’s Deore DX rear mech, then no, they don’t wear out, ever. It’s not possible. 😃😃😂


 
Posted : 09/04/2021 4:19 pm
Posts: 10933
Full Member
 

2mm allen key, some brake cleaner, some grease. You don’t want drop the little screws and lose them, so don’t try doing it on a gravel driveway or a deck with slots in it:) Video below.

Also be aware that the 2mm hex screws are easily rounded off by hamfisted people using old tools trying to rush the reassembly in poor light. Allegedly.


 
Posted : 09/04/2021 4:22 pm
Posts: 584
Free Member
 

You have a new mech every 6 months?!

Well, every 3 on average. I have 2 bikes, although admittedly the trail bike might do 9 months while the big bike will do 4-6


 
Posted : 09/04/2021 4:31 pm
Posts: 165
Free Member
 

My 96 Deore LX is still going strong, thousands of miles through everything on it and it works no issues.

my 19 Deore on the other had is toast.


 
Posted : 09/04/2021 4:33 pm
Posts: 2222
Free Member
 

Well, every 3 on average. I have 2 bikes, although admittedly the trail bike might do 9 months while the big bike will do 4-6

You're doing something very wrong then!


 
Posted : 09/04/2021 4:59 pm
Posts: 3783
Free Member
 

Try a new inner and outer cable first before you replace it.


 
Posted : 09/04/2021 5:29 pm
Posts: 7935
Free Member
 

I'm bemused someone even asked this question, the answer to which is 'Duh, yeah!'


 
Posted : 09/04/2021 5:45 pm
 Aidy
Posts: 2977
Free Member
 

I’m bemused someone even asked this question, the answer to which is ‘Duh, yeah!’

Well, yes - nearly everything wears out eventually. It's a question of timescale.

Pivots and springs in a rear mech will obviously wear over time. The 3 months above is fairly absurd, though. I'd expect to need to replace suspension bearings several times before you got to the natural lifespan of a rear mech.


 
Posted : 09/04/2021 5:55 pm
Posts: 3527
Free Member
 

Yes they develop slop (Shimano) where the jockey wheel cage is attached to the rest of the derailleur and some of the other pivot points. It can be difficult to feel when the whole thing is under tension! Depends where you ride and how much of beating your mech gets. Mine usually look pretty battered after a few months riding!

Something that is rarely mentioned is the fact the jockey wheel cage get's bent/twisted (11sp XT are soft as shite) so the upper and lower jockeys end up out of alignment.

Most bulletproof setup I've had featured a CNC'd cage. It was a lot stiffer than the Shimano one it replaced (got bounced off a lot of rocks round the lakes and peaks) and I got a year out of it with only 2 hanger realignments, 1 cable inner replacement and 2 adjustments for the new cables when stretched.


 
Posted : 09/04/2021 6:36 pm
Posts: 3527
Free Member
 

With Shimano clutches try to not lose the:

- The housing seal (grease it)
- The housing bolts
- The tiny metal clip thing
- Tension adjuster port cover (if it has one)

All have potential to fall on the floor and go missing! Also a tiny bit of loctite on the clutch tension bolt gives it a bit of resistance to undoing. I like a thin coat of moly driveshaft grease (NLGI 2) for the clutch wheel itself!


 
Posted : 09/04/2021 6:56 pm
Posts: 13594
Free Member
 

I'd change the cable before looking at the rear mech, they can fray at the shifter which causes shifting problems.


 
Posted : 09/04/2021 7:00 pm
Posts: 812
Free Member
 

Jees 6 months for a rear mech! I just sold an XT from 2005ish. Done thousands of miles. eBay buyer was chuffed to bits. I would go with hanger alignment.


 
Posted : 09/04/2021 8:44 pm
Posts: 1240
Full Member
 

Not sure I’ve ever had a ‘new’ one and they all seem to work fine. As a couple of folk have said, got some much older ones which do seem to have weathered better. But that could also be because I don’t rode the 9speed bike as much these days. In fact it’s currently in SS mode


 
Posted : 10/04/2021 6:55 pm
Posts: 5043
Full Member
 

My money would be on either cable needing replaced or hanger alignment.
Mechs can get sloppy of course, but I noticed (while cleaning) that my mech could be moved side to side (a lot) so I checked the hanger bolt, it took 2 full turns to tighten it up.
Shifting while it was so loose was still absolutely perfect.
That was on a 2015 xt setup on my Ebike.


 
Posted : 10/04/2021 7:14 pm
Posts: 4785
Full Member
Topic starter
 

<embarrassed admission>
It was the b-tension screw. Not correctly set when I changed from a larger cassette to my current one.
Similarly, chain is a link or two too long hence the dropping.

Shifting massively improved, will see if the dropping is also fixed or if I will be taking the thing apart to up the clutch tension.

Will be giving it a decent clean tomorrow too.


 
Posted : 10/04/2021 7:35 pm
Posts: 5043
Full Member
 

Excellent, at least it didn’t cost you a wheel.


 
Posted : 10/04/2021 8:40 pm
Posts: 0
Free Member
 

A new mech every 6 months? 🤣🤣🤣🤣🤣🤣


 
Posted : 10/04/2021 10:10 pm
 irc
Posts: 5332
Free Member
 

Your spare is just as likely to be bent. A proper tool is one of the best investments you can make.

My tourer got the hanger properly bent by airport handlers. After a LBS straightened it using the tool(steel frame) it was actually better than it had been before it got bent. Guess it must have been a few degreees out without me noticing.


 
Posted : 11/04/2021 1:31 pm