[Closed] Rough-running 12 speed

Everything was new in January and is not very worn.

Have you actually measured the chain?

Just done that now. It's just over 50% worn, but as I say, it has done this from new.

May be unrelated but GF had this on her FS recently and turned out to be aftermarket jockeys I had fitted for her. Roughness was only in largest couple gears and only under load. New OEM plastic jockeys sorted hers but I think issue may have been jockeys not handling chainline extreme maybe?

Back in the day (26″, 3×9)

Hey, for some of us it's still that day...

But, yeah, my thought was chainline and mech clearance.

Chainline? Guess there's not much i can do about that without going back to a triple chainset.

By chainline I probably meant is the BB/crank set up correctly with any appropriate spacers etc in the right place, so the chainring isn't sitting too far inboard/outboard?

Or maybe chain/cassette compatibility? Again, BITD, top-end and normal Shimano stuff didn't always play too well together, XTR was often different for the sake of it.

I'm grasping, admittedly...

Check whether the screws holding the mech hanger are tight as well as alignment - quite a lot of new bikes out the box need realigning IME

When everything is clean and dry, i have no issues, but in moderate mud, the drivetrain is extremely rough under load, making a loud graunchy sound, particularly towards the larger end of the cassette

So when your cassette/ chainring / chain are clean and dry they're quiet and when they're not / have a decent coating of organic grinding paste intertwined with them the heavily machined, closely interfacing component surfaces with minimal clearance between them sound rough and graunchy and the very same thing happened on your homebrew 10 speed CX bike when that was caked in shit??

Or maybe chain/cassette compatibility? Again, BITD, top-end and normal Shimano stuff didn’t always play too well together, XTR was often different for the sake of it.

I’m grasping, admittedly…

Yup you are, Shimano HG 12speed is readily interchangeable as the chain, chainring and cassette tooth profiles are machined to interact nicely with each other across the board, much like it's been for ages, well at least since the dawn of Shimano 10 speed in my experience.

Yeah I posted that Farage pic on the wrong thread, sorry

I have the same issue with 11spd xtr setup. Fine in the dry but as soon as it gets a bit wet it vibrates like crazy. Havnt diagnosed yet as it only happens under load but suspicion is the jockey wheels.

steve. My point was that my 1x12 set-up seems much worse in the mud than old 9 speed was. If this were simply how it is, i can't believe anyone would buy 12 speed, i doubt anyone would consider it acceptable. I therefore do not believe it is normal and wondered if people could point me to a particular problem.

also, i'm not talking about when it is "caked in shit", i'm talking about normal amount of mud, "moderate mud" i said, basically how it is after an hour of riding anything other than dry dusty trails.

Simon, chainline is totally stock, as i say, it's happened from new. Boost 148 rear end with the appropriate chainset. will check rear mech alignment. Can't be an issue with chain compatibility as it also happened with the stock low-end chain.

Simon, chainline is totally stock, as i say, it’s happened from new. Boost 148 rear end with the appropriate chainset. will check rear mech alignment. Can’t be an issue with chain compatibility as it also happened with the stock low-end chain.

Fair enough, Like I said, grasping...

(and FWIW, I thought Steve's reply was slightly, and unnecessarily, pissy too...)

Grasping as well but is chain on correct "way" - Shimano 12 speed chains have specific fitment. No idea what happens if fitted wrong way around

Thanks, but yes, it's the right way round, writing to the outside, plain on the inside.

Was kind of hoping someone would give me some justification to spurge on an XTR set-up. 🙁

Well way didn't you say!

It's definitely to do with the mix and match set up you've got, the only way to get it fully silent is to run a full XTR setup. Whisper quiet, they are, even in the most horrific of conditions.

You're welcome.

I experienced this on a new XT 12spd setup, as did a friend.

Perfectly fine in cleanish conditions but really, really noisy in mud, particularly sandy mud, which is what we have in our main rising area.

SRAM doesnt do it at all and I never found a 'solution', since I took it off and sold it and put SRAM GX back on, but I assumed it was clearance between the chain and adjacent sprockets.

ugh.
Thanks.

I don't actually want to replace everything with SRAM. I was actually hoping that swapping one component, like running a SRAM chain, or a better cassette, might fix it.

Maybe the solution is to have a bottle on the bike and squirt water on the cassette every few minutes. 🙂

Another grasping at straws... what model is the mech?

A bunch of people (including me) have trashed the inner plate on the SLX 12 spd mech... chain seems to pop off the top jockey under certain conditions and eats the plate. No marks on inner plate around that area?

Currently running 1x12 SLX cassette, XT rear mech, XTR chain and XTR 34t chainring.

I don't get these issues. It's not quite as smooth when mucky but certainly not grinding like you describe. Now when I had a Burgtech chainring (supposedly shimano 12s compatible) it was a different story, that thing caused all sorts of horrible issues that you wouldn't normally put down to chainring.

Just done that now. It’s just over 50% worn, but as I say, it has done this from new.

At 0.5?

Replace the chain.

@gingerflash, I've been having the same problem. SLX chain and cassette, very grumbly in easier gears. I made some tweaks today which have got it back to normal in mud.

- reduced the b tension, so much that it's actually less than the marking on the back if the mech suggests

- replaced the jockey wheels but yours are probably ok at that age (mine are 2.5 years old)

- made sure the mech is as straight as it's designed to be

- put of more chain lube than usual.

The chainline is totally rubbish and I think that's the real cause. Mines a boost bike with a non boost chainring and I can't imagine how bad it would be with a boost ring. The chain is scraping off the wide teeth as it leaves the ring already. But there's nothing I can do about that.

Was going to mention the b-tension.. I've found with mine that it's noisy unless you have the b-tension at the exact right spot (per the marking on the rear of the cage)

Also if you are checking the mech for bends, be aware that the cage is supposed to bend slightly towards the wheel rather than being completely straight.

For what it's worth, it's not supposed to be noisy like that, mine has been pretty much silent it's entire life (XT chain, XT cassette, XTR mech), that's including nasty mud soaked days, long days in the winter through 12"+ of snow and frozen mud, it's just kept on truckin' with barely a complaint. Cassette and chainring are at 18months old now, mech is getting on for 3 years I think (transferred from old bike where it performed flawlessly on a SRAM GX cassette), and it's the 2nd chain I've run which is still well below .5mm. I've used exclusively rock'n'roll extreme on it which I am sure helps as the chain stays very nice and clean, just a fresh application before every ride.

thank you, will have a look at b-tension.

i do think the chainline and tall teeth on the jockey wheels might be an issue.

i had similar problems with dura-ace 9100. the new design mech wraps the chain round the cassette more, so the upper jockey wheel is much more forward. this means taller teeth are needed to make the shifts. the taller teeth then cause rough running at certain chainlines. i did try jockey wheels with less pronounced teeth. it ran more smoothly but then the shifting was rubbish. it got a bit smoother after 1000 mjles or so, i guess as the teeth wore down and lost their sharper edges.

interesting that an XT/XTR set-up doesn't do it. wonder if it really is just set-up, or whether the better components just play more nicely in the mud, as was my experience of old 9 speed XTR.

12 speed is just crap in the mud. Fine in teh dry but if you actually ride in the rain and get crud everywhere it just performs poorly. the tolerances for setup for real world use, and abuse, are so fine its stupid. any little knock or twig or debris and it just doesnt work properly.

when my current cassette fails i'm going back to 10speed. my 10speed kit on all my other bikes is a few years old and running fine. i get less than a year out of 12 speed drivetrains.

Its 100% emprerors new clothes and marketing bullshit.

i had similar problems with dura-ace 9100. the new design mech wraps the chain round the cassette more, so the upper jockey wheel is much more forward. this means taller teeth are needed to make the shifts. the taller teeth then cause rough running at certain chainlines. i did try jockey wheels with less pronounced teeth. it ran more smoothly but then the shifting was rubbish. it got a bit smoother after 1000 mjles or so, i guess as the teeth wore down and lost their sharper edges.

I had issues with slightly slow shifting and a generally noisy drivetrain with Ultegra R8000 Di2 for a while until I did a bit of reading on chain length.  Everything you pointed out about the increased chain wrap is correct and tallies with my experience and research, but I came across a number of articles looking at chain length with the new style mechs and after following the advice on the articles and essentially running the chain at the longer end of the range specified by Shimano, the problems and noise all went away.  Basically the advice is that when you measure chain length as per Shimano instructions (wrap the chain around big-big and add either 1 or 3 links depending on where the ends of the chain meet), you should always add the 3 links rather than 1. ( I think I'm remembering that correctly).

Quick search and here is similar details for 12 speed MTB chain length.  Might be worth looking into.

https://dansbikeblog.com/article/how-calculate-correct-chain-length-shimano-12-speed-drivetrain

#EDIT: And here's the link to the original information I found with regards to road groups..

https://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=152332&sid=f064d9c5928bcd6ad99977da64e6d110

I've been holding off opening this thread as I was hoping to continue in my deluded hope that Shimano 12 speed isn't shit.

I have exactly the same issues as the OP with brand new XT kit. It was so bad I just gave up riding the bike in the Peak unless the weather has been dry for weeks.
When I do go out and there's a big gritty puddle I'll either go very slowly or get off the bike and carry it. It's ****ing stupid, but if I don't then the next 2km is just a cacophony of nightmare proportions.

It's not so bad in clean water, so I've taken to driving the extra hundred miles to the Lakes instead of the Peak.

Weather outside is gorgeous, but I know I need to wait a few more days till it is bone dry to go riding off road.

I think it got slightly better when the drive chain bedded in, but can't be sure as I have just given up riding sandy/muddy trails on the wet.

My mucky ride on mine yesterday was silent after making the changes I listed above. I've changed my mind and think actually the B tension is the main reason it's now quiet. As I was fettling it I did wonder if some extra chain length would help too, as it would help wrap in the bigger cogs, so it's interesting to see Highlander's post.

I suspect a lot of people running 12 speed who build their own bikes and have done for years have built them up with chains that are too short.

I'll be sticking with Shimano 12 speed. It shifts so much better than 11 speed, and is lasting well. It also shifts a thousand times better than the Sram GX eagle set up I used on a borrowed bike earlier this year which felt like it was Shimano Tourney or something.

I suspect a lot of people running 12 speed who build their own bikes and have done for years have built them up with chains that are too short.

This was pretty much the conclusion by the chap who made the post in the second link, it seems that the rules governing chain length are sufficiently different that the old methods to determine chain length that everyone from factory bike builders down through LBS mechanics to home mechanics uses are basically wrong and resulting in noisy drivetrains with chains that are too short.  My experience resulted in me changing the factory fitted chain on my Canyon road bike which was noisy exactly as described with a fresh chain that was 2 links longer and ran silently in all gears.

Is it a boost offset chainring or crank on an otherwise non boost frame and hub?

Chain length
B tension

I binned the finickity 12 for 11 speed deore 11-51 and never looked back.

Was kind of hoping someone would give me some justification to spurge on an XTR set-up

If it helps, I have 12-speed XTR on my 2020 Stumpy and it runs very smoothly. The last few weeks have been pretty grotty, lots of mud on the ride in and lots of muddy, gritty, puddles all the way round (Swinley). No noise from the drive train, just me grunting and groaning.

The fact that it all works just fine I am attributing to this being my first complete bike for over 20 years. I've had similar sounding problems to yours over the years, usually down to my ham fisted approach to bike building (YMMV of course!)

The main reason for the grinding in mucky conditions is that Shimano Dynamic Chain Engagement+ has much more engagement between the chain plates and the chainring teeth. The chain plates are extended so as to mesh with the tooth in a way SRAM does not.

The 12speed shimano chain is quite a bit narrower than KMC and Sram 12speed.

Now you can see why if you put a sram/kmc 12speed chain on your 12speed shimano it is much quieter in the muck - lots more clearance than the shimano chain - just some chain bits i found in the shed - couldn't find any eagle bits but is similar to KMC X12. - apols for bad shadows and fluff.

see the extended parts of the shimano chain in red circles

[img] [/img]
[img] [/img]

more details here:
https://bike.shimano.com/en-EU/technologies/component/details/dynamic-chain-engagement-plus.html

as for chain length Shimano guide is on pages 13 and 14 here:

though doesn't seem to hold for those (not many perhaps) using the short cage XTR / XT 12speed 1x rear mechs that match the 10-45cassette.