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In last 6 years I have gone from from 9s Sram to 11s Shimano to 12s Sram to 12s Shimano.
I've been riding for nearly 25 years, and in that time I have killed one mech from poor adjustment of the limits screws, and one from running a chain too short.
And yet in the last year I have had 3 Shimano 12s rear mechs bend so badly that they had to be retired. 2x Deore, 1x SLX. It seems that the cage is very vulnerable to catching on passing rocks. The shape of the Shimano cage seems more vulnerable than the Sram eagle design. On top of that the cage is very easily bent. It can be 'adjusted' with just one hand. Is anyone else experiencing this?
I have just ordered a new Sram mech and shifter. I was tempted by AXS but that would be a bold decision based on my recent experience.
They seem to be more prone to rock strikes given the length of the cage. A work colleague is always breaking mechs.
The cages aren't as strong as the 10 speed and older stuff - weight weenie priorities.
Nope, not happened to my XTR, but then again that is made of Carbon so bending really isn't an option.
mate had this over the weekend on his Bird with 12s Shimano. Looked ok, but couldn't index it right. We threw spare mech on and within 2 mins we had it indexed and working perfectly.
I'm another who has had a suspected slightly bent 12s XT mech as the cause of some long term indexing woes. Although it hasn't been my only 12s issue. Also wore out a Deore one in about 5 minutes, which was never quite perfect shifting. Recently replaced a cassette under warranty too (Garbaruk, no quibbles, great service, weird issue with one cog). And separately moved to AXS. Currently, shifting is tickety boo but then every part is brand spankers and silly money. Let's see what happens next.
I also never had issues with 9, 10 or 11 speed and still have most of it running.
Yup same here, I bent one on Eyam moor. The bent one kept 'grinding' a funny noise in the lower gears but it indexed fine and shifted fine. Replaced with another Deore and the noise went away.
An XTR with carbon cage might be my next stop if GX Eagle is no good
The issue I have is actually the lower cage. The top and bottom jockey wheels are no longer co-planar, and it's quite noticeable to the naked eye.
Yeah, I've found that on the XT rear mech - gets bent quite easily but so far also been able to bend it back to straight by hand - thing really is made of a very warm soft cheese.
650b? I find they run big capacity mechs too close to the ground
The issue I have is actually the lower cage. The top and bottom jockey wheels are no longer co-planar, and it’s quite noticeable to the naked eye.
The top and bottom jockey wheels look a little out of alignment to the naked eye on all 12s shimano mechs. They are supposed to be like that, not saying that your issue isn’t a bent mech but bending the cage to have the jockeys wheels aligned will mess up the indexing at one end of the cassette or the other.
You do realise they are supposed to be bent. I, like most, have made the mistake of assuming they are bent and tried to straighten them. Don't!
I've just bent one too
Went with Deore as a replacement. If that doesn't last I'm ditching 12 speed!
My kids 7 speed is so solid by comparison. Maybe that's the way forward. Lol
I have a feeling if you were disappointed by the longevity of a higher end Shimano 12s mech you'll be even more disappointed by the longevity of a Deore one. I did the same thing. Mech 3 was back to an XT. Mech 4 is AXS. When put like that my record sounds disastrous, but TBF The first XT bent and the 2nd XT is probably totally fine, I just fancied a change. Deore in the middle got sloppy pivots in one summer's use.
Yeah I still have 9 speed on my old Hardtail and it's absolutely solid, never fails, never loses index and shifts are crisp.
The Shimano 12spd XTR mechs don’t give the same impression of quality as the 11spd ones did. Feel much cheaper. I do prefer SRAM 12 speed. Never had an issue with it’s longevity as some have though.
The ball bearings in the lower jockey wheel of my SLX 12 speed mech have disintegrated and fallen out in about 700 km of pretty easy use.
EDIT
then my XT 11 speed mechs didn't fare much better. Come back SRAM XO 10 speed. The pinnacle of rear derailleurs 🙂
A very timely thread. My Year old xt *looks* fine (but it’s very hard to tell because of the shape. But I’ve eliminated chain, cassette and hanger so its the only thing left. H
It’s not even showing much evidence of rock strikes (and it survived a bent hanger absolutely fine).
A bit of yanking around doesn’t seem to be fixing it do new mech on order.
Interesting video. That the bottom cage is meant to be bent and twisted makes it impossible to check for damage or repair.
So new mech arrived today and it fixed my shifting issues. Holding the two next to each other I could not work out where the old one was out of shape at all. There was *maybe* a tiny bit of movement in the cage pivot but really couldn't be sure. There doesn't seem to be a single straight line on the thing you can take a reference from.
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I did a couple of XT's in quick succession. Gentle knocks on rocks. Back to SRAM XO and no issues.
Not sure if anyone else has mentioned this. But Shimano derailleurs are supposed to be bent. Well, the cage is. It's so it aligns better with the front chainring in the extreme gears.
Of course if you've hit a rock and bent it more, then there is going to be an issue.
or search loveMTB Shimano not bent ansd twisted on YouTube.
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Not sure if anyone else has mentioned this. But Shimano derailleurs are supposed to be bent. Well, the cage is. It’s so it aligns better with the front chainring in the extreme gears.
Of course if you’ve hit a rock and bent it more, then there is going to be an issue.
or search loveMTB Shimano not bent ansd twisted on YouTube
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Someone didn't even look at the thread before posting did they.?? 😛
I've banged on about this problem for a while. I noticed it when aftermarket wide range cassettes first came out. I found 11 speed (XT and SLX) Shimano mechs much more fragile than 10 speed on the same cassettes. I posted about running 11 speed mechs on 10 speed years back when it was a new thing! You can bend and twist the cages with hand pressure, the metal is so soft (not fit for purpose IMO) and as mentioned the cages are curved and contoured, making it PITA to get them straight once bent. I've split cages and banged the two halves flat with a hammer in the past!
Those CNC'd Rad Cage mods were great on 10 speed mechs. Made a real difference to the robustness of the cage, stiffened it right up. The best most bulletproof (wide range 1x10) setup I've run to date. Only had to deal with bent hangers and corroded cables ****ing indexing up!
So, K did the cage on her XT 12s at the weekend (hooked it on a bit of fallen tree, bent cage). Did the usual hour of comparing new and old and trying to work out whether could bend it back into shape before giving up.
HOWEVER, it does appear you can now actually buy more spares for Shimano mechs than you used to be able to, and since there's no longer a constant supply of heavily discounted OEM parts it's actually economic to repair them. Cages (inner and outer separately) are listed by SJS and quite a few Euro sites, and it looks like both sides come to about £30. However, it's clearly enough of an issue that nowhere has them in stock (best I found was 'expected in c8 weeks) but I've bought a couple of sets from AliExpress £65 inc delivery and taxes.
I use a 10-45 12spcassette with 30t chainring and then use the short cage 1x mech which you can get with XT and XTR which gives quite a bit more cage to ground clearance.
Wonder if shimano will bring out the short cage 1x mech for SLX and Deore.
Agree that the quality of 12sp shimano stuff does seem to have dipped from their 10sp stuff.