Repair, replace or upgrade…what would STW do?!?

So….as seems to be an annual event (sometimes shorter) I’m sitting here with an SLX M7100 12sp derailleur that has eaten itself once more…

I have bought spare parts for this and repaired it several times (plus replaced once when I couldn’t work out HOW to repair) and feel it’s getting a little much

Thinking of options I’ve come to the conclusion I have three…

– Repair (again)
– Upgrade to another Shimano derailleur that’s compatible with my current M7100 shifter (but to what)
– Replace altogether and look at a SRAM NX / GX (or other) groupset but this will be probably be used due to budget and all that funniness

Getting a bit tired of polishing the turd that is an SLX derailleur but it’s always the cheapest option…

VERY limited experience with SRAM group sets as I’ve never had them so feel a little bit blind, what is the opinions on these over Shimano?!

WWSTD?!?

Thoughts, comments, suggestions…throw them at me

SRAM works, but it apparently doesn’t have the die hard longevity that Shimano does (or doesn’t in your case). Would moving up to XT be an option? I’d assume that was even better for longevity.

I swapped my SLX mech for SRAM GX when it died, keeping the Shimano cassette. Works better than the SLX ever did.

I do prefer SRAM though & have had no issues with GX or NX, so was an easy decision.

Shimano Deore RD-M6100 Deore rear derailleur; 12-speed; Shadow+ SGS long cage

Pop a Deore on?

Before doing any of the above I’d work out why it keeps having problems.

Alignment issue? Dodgy hanger? Chain run too loose/tight? Do you keep bashing it on rocks? Zero maintenance and it rusts itself solid? I think I’ve broken about three mecha in twenty five years so my first thought is that there is something wrong somewhere and unless you can rectify that too it will keep happening

Fit a rohloff.  Thats what I would do

@tj, if you can source a Rohlof for me at SLX prices I will be very happy indeed.

Main issues with the mech are the same as what many people, after reading and posting various threads on here, suffer from, mostly cages being made of butter and bending too easily or just breaking, also chain jumping off of the jockey wheels when back-pedalling or changing gear too quickly and getting mangled within the cage, it seems these are inherent issues with this mech

I’ve had my chain length, hanger and frame checked for abnormalities I’ve had the mech checked for anything untoward and each time coming back with nothing to report,

New chain fitted a couple of times just in case it was an issue with running new cage / old chain

Re: maintenance, I like to think I keep on top of it well, wash down after and full check before any ride. Full strip down, clean and re-grease 2-3 times a year so I’m not sure that’s my issue

As said, just SEEMS to be an inherent issue with this particular derailleur

It was mentioned last time I had the issue on here that I could use a “better made” deore (MIGHT have been XT, I’ll have to double check) cage and jockey wheels but couldn’t find any in stock at the time so went back to ordering the M7100 specific version

just getting a bit bored of the same repair job time and time again hence consideration for the change

if I’ve got this right…

XT mech would be a step up from what I have

Deore mech also worth a look

GX / NX generally no problems other than possible longevity issues

if you can source a Rohlof for me at SLX prices I will be very happy indeed.

I reckon they pay for themselves over time.  5 – 10 years depending on milage.  Chains last a lot longer, no mechs to break, no cassettes to buy just a small cog.  took us around 5 years to be into savings on the tandem

As you’ve not got longevity then SRAM would be fine. I’ve not had longevity issues with SRAM, so unsure what issues are there.
If the cage is failing, can you get an aftermarket stronger one and fit that? Xt should last longer, but suspect it may also have a cheese cage – I’ve no idea.

Fit a rohloff.  Thats what I would do

Done that and it was expensively shit for trail riding. Ruined the handling of a nice bike at speed

Removed it again

If the cage is failing, can you get an aftermarket stronger one and fit that?

id also had that thought but I’m not so great at working out what’s what or what would be suitable / fit, that’s why STW has been my saviour many times over ha ha

unfortunately Rohlof is well off the table as it’s just too expensive for me right now, I’d also loath to get rid of my Supadrive hub, bombproof and that sound…makes the most wonderful racket ha ha

going to look into XT mechs I think and keep a loose eye on used SRAM group sets, I figure, at this point, can’t get much worse, right?!

Done that and it was expensively shit for trail riding. Ruined the handling of a nice bike at speed

have also heard this many times…

Just a cursory glance at the images on Shimano’s website. The only differences I can see between the cages for M6100, M7100, M8100 and M9100 are the cutouts and profiling to make it lighter on higher spec models. I’ve often used jockey wheels off lower end versions, including Road, even though they are not shown as compatible. The only difference being the cutouts and bearings for XTR!

It MAY (I don’t know for sure) be possible to fit a cage from XTR, XT or Deore assuming they are not just as bad! I have bought the front and back plates that make up a cage from SJS and JE James before now.

Before one of the forum smart arses pipes up there is a caveat here. It’s obviously not possible where mechs are a completely different design between spec levels or have a different tooth count, as was the case with some of the older designs. You could probably get to the bottom of that by looking at Shimanos schematics.

Doesn’t the m5100 also work?? Seems to be 35gbp.

Interesting because i’m going something similar with the same derailleur!

Son’s bike came with SLX and a 51 tooth cassette. Worked fine until it didn’t. Spent an age trying to get it right then gave up and bought a new one.

6 months later same issue (he doesn’t ride a huge amount so it’s not much wear). Specifically, it will change up the cog fine, but won’t drop down from there … all screws are set up perfectly, hanger is straight, cage is undamaged, cable checked (if i push the gear up manually it will drop back down). If I loosen off the clutch completely it will change so I’m assuming it’s something there… but when i pull the cover it’s absolutely mint.

But … i’ve put the old one on my hardtail with 11-speed 46 tooth cassette and it works great!

GX on two bikes, oldest is from 2018. Brilliant groupset IMO. I used to be a big Shimano fan (still have it on my road and gravel bikes), but would need some convincing to away from SRAM GX.

Shimano rear mechs were notorious for weak springs in the past, maybe that could be the case here too?

The only differences I can see between the cages for M6100, M7100, M8100 and M9100 are the cutouts and profiling to make
it lighter on higher spec models

They may look similar, but they’re not.

SLX & XT are made from 7075-T651 Aluminium Alloy, XTR is alloy inner & carbon outer

As for the OP, bang an XT on there, they’re pretty good. Personally I’m on XTR and mine is currently 4.5years old and as good as the day I got it.

Well, I’ve used XT rear mechs since the early 90s and never had a single one break. So get an XT.

I do have an XO on a 12 spd bike and that is quite a nice thing. But no doubt a lot pricier.

That said, I’ve got a STX-RC on an old bike that’s still going ok. See if you can get one of those. It is 8 speed though.

I fitted the Deore (steel) cage to my SLX 7100 and cured the issues – which I think was flex in the cage allowing chain to chew the inner plates up a bit – then it was only a matter of time before it jammed.

I would just buy a Deore mech – seem bombproof.

Starting to think a new Shimano mech Will be the next best thing to repairing the old one

Because I’m not as au fait with gear and gubbins as I probably could be, is anyone kind enough to share any links to any recommended 12 speed mechs (deore & XT specifically) that would work with my current M7100 shifter please? just so I know what I’m looking for / at…

@donslow, this is the Deore one to look for:

https://bike.shimano.com/en-EU/product/component/deore-m6100/RD-M6100-SGS.html

I’ve got the same SLX M7100 12sp on two bikes – bought SLX before I was aware of their cheese-like quality – and have a spare Deore for when the inevitable happens. I’ve been OK with them both so far though.

Deore M6100

https://www.merlincycles.com/shimano-deore-m6100-shadow-plus-rear-derailleur-12-speed-202413.html

Deore M5100

https://www.halfords.com/cycling/bike-parts/gears-drivetrain-and-cables/shimano-deore-rd-m5100-11-speed-rear-derailleur-sgs-long-cage-432374.html

XT M8100

https://www.bikeparts.co.uk/products/shimano-deore-xt-rd-m8100-xt-12-speed-rear-derailleur-shadow-43-gs-for-single

As someone mentioned above the M5100 is the same as the M6100. Compared in the video below

Previous threads about SLX mechs

https://singletrackworld.com/forum/topic/are-12s-slx-mechs-a-bit-rubbish-or/

https://singletrackworld.com/forum/topic/12sp-rear-mechs-then/

^ that XT at Biketart is a GS cage for 43t cassette.

My Rise came with an SLX mech which I bent on a rock. Swapped the cage which I then bent on a rock. Got an XT in a sale somewhere. I bent that on a rock and it went into the wheel, removing a spoke. Bought new inner and out plates. Next time, I’ll just buy a Deore.

To me, they’re so flimsy that they’re basically a consumable now so I’ll just go with the cheapest. Never had problems with 11sp

Cheers all, appreciate the help, definitely some bits to mull over until pay comes back around…

After 3 xt mechs to my one sram XO my son decided to to give Sram GX a go. All he did was change mech everything else worked fine. Also he had to run chain device on xt to stop repeatedly dropping chains never had that issue on spam.

I went through a few SLX mechs too, now I just stick a Deore on for £45 odd and replace it when it needs it. I can’t say I notice a difference in shifting between Deore and SLX, possibly a bit more chain slap on big impacts with Deore but could have been there on the SLX too and I don’t remember.

I have been running SLX M7100 derailleurs for a few years now and went through the cage eating issues. Found that the cure is to replace the jockey wheels. I have XT M8100 ones on one bike and Hopes (bling!!) on another and have had zero issues with either ever since.

Still regulary check them. Oh and SJS Cycles usually have the cage parts (Deore/SLX/XT/XTR are all interchangeable) & jockey wheels available

XT Jockey wheels
https://www.sjscycles.co.uk/gear-spares/shimano-deore-xt-rdm8100-tension-guide-pulley-set-y3fw98010/

Deore Inner cage
https://www.sjscycles.co.uk/gear-spares/shimano-deore-rdm6100-inner-plate-sgs-type-y3hk26000/?sessionid=5193cab1fe7809f8245b6323eda6bb2f3ee4d762