12sp rear mechs, then

I still prefer SRAM, but that brings a different complexity of swapping of course.

are you sure it's not the hanger ? Floppy in what direction ? is the bolt tight ? is the clutch 'on' ?

What the heck is long cage "PDI" ?

Mleh, it's hard to get excited about mechs these day. Deore is a shadow mech, has a the variable clutch it's not the weight of a small boat anchor, good luck finding an SLX mech, last time I look they were like hen's teeth. XT has always been my go-to in the past, but these days I'm less bothered with what's written on the side of it, as they all seem pretty reliable - unless you crash them obvs.

Hanger has been checked with my alignment tool. It's floppy in a sideways direction. Yes, bolt is tight.

I still prefer SRAM

Me too, feels like Shimano have been lagging behind for years now. They just seem to react to what SRAM do, but without feeling like they're heart's in it anymore.

I've not had much luck with 12 speed Shimano. Been decades since I ever had gear system trouble, but the 12 speed on the bike I built in 2020 has been fiddly/finicky/untrustworthy from the start and I've had two Shimano XT mechs go bad, whether slightly bent, damaged, 'floppy' just as you describe.

SJS cyles had the best price for XT last time I replaced. Next time I'll go with Deore. I might even try thr forbidden fruit of SRAM - I think they seeem to have had more succes with 12 speed.

On the bike I built this year - I used my trusty 11 Speed XTR kit with a HG freehub, and a SunnRace 11-46 casette. And you know what - its got all the range I need, and it works absolutely beautifully - at least 6 years of use onthe mech and shifter, and they are both like new.

Colour me 12 speed cynical - I think they jumped the shark, frankly.

SLX are decent. When my XT got smashed I winced at the XT cost and found the SLX performed the same with a tiny weight penalty. Only other difference is no rubber port to adjust clutch without taking the plastic cap off. But that's a non-issue.

In stock at merlin.

Did anyone ever get excited about mechs?

I've had all the Shimano 12 speed mechs. In use, I cannot really tell the difference between them.

The Deore and XTR ones seemed to last the longest for me. YMMV.

Make sure you pinch the clutch off the old one to keep for spares.

the deore m5100 (although marketed as 11 speed 11-51) is fully 12 speed compatible and decent pricing.  I picked up 4 brand new ones for 20 quid each on and off over the last year.

I spend more on the shifter and less on the rear mech.  rear mechs get smashed, shifters really control the feel of the shift.

I was a huge Shimano fanboy but their take on 11 speed was a bit half-arsed. When it came to buying a new bike during pandemic my usual go-to Shimano XT was impossible to get hold of in 12 speed so I settled for SRAM Eagle GX. Been hugely impressed.

Nearly 2,000 pain-free miles on the GX mech and still looking and feeling like new. Chain got to 1,600 miles when it hit 0.5% wear which is around double what I'd usually get with an XT chain.

SRAM are directly compatible?

Supposedly so - https://turncranks.com/shimano-12-speed-shifter-with-sram-rear-derailleur/ - but I've not personally tried it.

We have been running GX Eagle on some bikes since they were released so back end of 2017 and they are still going strong.

Latest couple of bikes have come with Eagle AXS and I've been even more impressed.

If I had to buy new now to replace then i would bite the bullet and fir a GX Eagle AXS upgrade kit. I do have a couple of spare Eagle mechs to use up first though so it may never happen.

Although I run Saint brakes I couldn't be tempted to go back to the drivetrain

I might even try thr forbidden fruit of SRAM

Honestly, when I bought my Spesh Enduro 5 years ago I had the replacement for the SRAM drivetrain in several on line baskets for when I was sure it would just explode on me. It's been the best performing drivetrain I've ever had, and that includes Shimano 9 and 10 sp. stuff. It just wipes the floor with them in terms of longevity and reliability. The only thing I miss is the lightness of Hyperglide, and push-pull triggers on shifters, Shimano would have to bring out some miracle product to make me look at their stuff now.

They're definitely compatible. I bent a GX eagle mech and couldn't get one. Managed to find an SLX one (which was about half the cost of the GX), and works like a dream with the GX shifter and all the rest. No issues.

I do miss the little lock button on the SRAM one though, very handy for removing the wheel etc.

Deore is a shadow mech, has a the variable clutch it’s not the weight of a small boat anchor

I bought a couple cheap as spares, since they work with 11sp as well.

Was surprised how heavy they are.

The only 12sp mech I've used was SLX and I was disappointed with how easily that bent. Dunno if XT is tougher, maybe just stick with Deore if they are still under £30?

devash

I was a huge Shimano fanboy but their take on 11 speed was a bit half-arsed. When it came to buying a new bike during pandemic my usual go-to Shimano XT was impossible to get hold of in 12 speed so I settled for SRAM Eagle GX. Been hugely impressed.

I was always firmly in the Shimano camp too, had one dalliance with SRAM 10sp which exploded as expected and ended up mangled in my spokes. I bought 11sp XTR pretty much the day it came out and it lasted incredibly well, but now across 5 bikes, the only Shimano part on any of them is a set of rotors on the pub bike and maybe a few lengths of SP41.

Same as you, tried mechanical GX eagle with X01 shifter, was really impressed, then got seduced by AXS when the 11 speed finally wore out.

I’ve just purchased a new XT mech and SLX chain from Biketart for £96 with priority delivery. LBS was £110 for just the mech.

Hopefully it’s here tomorrow as mine derailed itself last night.

This was after straightening to see if I could salvage the jockey wheels, they were both broken through.

You can now get wide range 10 and 11 speed setups that almost match 12 speed and should cover what most people need so there's always the option to downgrade. Cheaper parts and not as difficult to setup and keep running smoothly.

You can now get wide range 10 and 11 speed setups that almost match 12 speed and should cover what most people need so there’s always the option to downgrade. Cheaper parts and not as difficult to setup and keep running smoothly.

Good point and I've stuck with 11sp myself, but I reckon OP has a microspline hub so his options will be limited in that regard.

I wouldn't bother going to SLX - the cage is alloy and bends easier than Deore. I ended up fitting a Deore steel cage (spare parts from SJS) to my SLX mech recently after another bend issue.

I do miss the little lock button on the SRAM one though, very handy for removing the wheel etc.

My Rise has Shimano and I swear at it every time I have to put the the back wheel in. SRAM make it so easy with the lock, when don’t Shimano have it? 😢

Problem solved, by the look of it. Seems that whilst the bolt was tight; the mech had been knocked round in the crash but the bolt had held it in that position. So it was equivalent to having the B screw wound in much too far. This led to the gap between jockey wheel and cassette being too big, so shifting was less effective.

Re comment above, slx rear mechs 69.99 at merlin

Just replaced a slx with a newer slx. All good

12 sp wise I've got a Shimano XT that is new but seems to be nice and smooth + was easy to set up. Had a Sram SX which was terrible and never indexed properly.

Problem with SLX is the jockey wheels are bushes not bearings, I paid the extra £12 for the XT for this reason.

Funny how Shimano only ever had those dinner plate jockey wheels on really cheap Alivio and lower mechs. Then Sram jockey wheels were all big and now I find my new XT mech has big dinner plate jockeys! Don't half get tangled up with bits of grass and weeds don't they.

My m6100 deore mech snapped in the same way as in that pic. Shop said they’d seen a few do the same. I got mine refunded under warranty.

I wouldn’t bother going to SLX – the cage is alloy and bends easier than Deore. I ended up fitting a Deore steel cage (spare parts from SJS) to my SLX mech recently after another bend issue.

IIRC the Deore cage is all steel, XT is all alloy, SLX is half and half.

Problem with SLX is the jockey wheels are bushes not bearings, I paid the extra £12 for the XT for this reason.

Bushes not necessarily a bad thing according to some people (see various old threads on here).

Bushes not necessarily a bad thing according to some people (see various old threads on here).

Because the little bearings seize and become bushings anyway?

Did anyone ever get excited about mechs?

I still pine for the halcyon days of Shimano Rapid Rise rear mechs, so yes 🙂

I run 10-speed Shimano on both my main mountain bikes. Affordable, reliable and enough range for my legs anyway.

Because the little bearings seize and become bushings anyway?

Bearings can wear and give excessive twisting play. This means the jockey wheel can twist and allow the chain to jam between the cage and the wheel causing an unscheduled creative dissasembly.

Bushes can get loose but don't end up like this. Better still are ceramic ones because they are as hard as the grit if not harder.

Bearings can wear and give excessive twisting play. This means the jockey wheel can twist and allow the chain to jam between the cage and the wheel causing an unscheduled creative dissasembly.

Had this last year with an M8000 mech, causing me to come off quite painfully. I was aware the bearings were going but thought I'd get a few more rides out of them as the teeth weren't too worn.

I had SLX bushings develop excessive play causing the chain to come off and jam up between the jockey wheel and cage.

Seems mostly the issues are people trying to run things for too long then without replacing them 😀

Didn't have many miles in them, hence the lack of teeth wear.

Bushed jockey wheels definitely show too much play to keep proper alignment on the big 13t versions you find on 12s mechs. But then bearings seize.

The least irritating solution I’ve found is a to pack the bearing ones with a stickier grease from nee (blue stuff hope use seems good). A little bit of faff and would probably cost me a few watts over a 10 mile tt but they last for ages- I usually wear out jockey wheels from the outside not the inside now.

Always used to be the opposite for me. The original teeth on that mech's jockeys wore right down but the bearings were still good at 4000+km.
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By contrast, a couple of sets of jockeys later, the ones that had me OTB had a lot less miles and less worn teeth, but I'd had to repack the bearings twice. Does make me wonder if they're using a lower grade of bearing now.
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XT over SLX everytime, I too have suffered with the chain getting stuck in the jockey wheels on an almost new mech. Eventually this happened and bent the mech beyond use.

Prior to 12 Speed, I’ve always worn out the teeth before the bearing or bushing.

I also regularly grease jockey wheel bearings every few months when doing a deep clean of the drivetrain.

I am planning to put Putoline on my jockey wheel bushings...