[Closed] Underwhelmed by XT 12 speed

Is your chain on the correct was round?

What front ring are you using? Wolftooth?

Try adjusting the B screw away from the guide line on the mech to see if it helps. There is a large range of tolerance in this, all bikes are diferent shapes.

I get what you mean to be honest. I swapped my 12 speed GX for SLX after the mech got tired of life when pedalling on a flat bit of ground.

Shifting under load is great... when it works (which is about 1 in 3 times). Any other time is seems as clunky as anything else.

For the most part it robust and fuss-free, but it started complaining slightly in the wet yesterday. Tried skipping gears a few times and didn't sound great. That could have just been mud/grit though.

On the plus side, consumables are cheaper and overall I think I prefer it.

Have you checked the gear hanger for alignment? In my experience, the bigger the cassette gets the more correct alignment is critical.

Is your chain on the correct was round?

What front ring are you using? Wolftooth?

I believe the chain is on the right way up. Using a Northshore billet HG12 compatible ring - seems quiet and is retaining the chain perfectly. It’s a boost bike and boost spaced chainring.

It was working fine when clean - it just seems more susceptible to skipping when a bit muddy. Not talking biblical stocky mud - more quite runny / flicky mud.

Maybe I’ll play with the b screw a bit and see if that helps.

On XT here since May on a new bike and I have had a similar sense that it's just not quite right. Done all the normal things but I also had a slightly sticky link which it is worth having a careful check for. It didn't do it all the time and felt free enough in the hand, loosening it off made no difference so I replaced it.

I've never before had an issue with indexing but on this kit it just seems really sensitive and never quite right. B tension has to be right, as is well documented, and I'll have another try to see if moving it a little one way or other off the guide line improves things.

Got some Putoline residue on the cassette now having just done that job, which could maybe do with a really good scrub, but that's never been an issue before.

On chain orientation I'd understood that it just had to have the printing on the outside. It should be up/down symmetrical? Printing isn't consistently one way.

Admittedly I'm using a deore mech and slx shifter with an nx eagle cassette but I noticed if I set the mech as per the curvy line on the back of the cage, mine struggled to shift into the higher gears(lower down the cassette) with a bit of trail and error with the b screw and shifter tension it turns out my bike works best when the line overlaps the teeth on the largest cog ever so slightly.
Set this way, my gears work perfectly both up and down the cassette... Even so far as I'm having to look down to see if it's even shifted its honestly that smooth in some of the gears.

Mine's not on the line, it needed more b-screw to stop it skipping on the 10t under power.

Still shifts better than SRAM, clean or dirty.

Mine’s not on the line, it needed more b-screw to stop it skipping on the 10t under power.

Exactly the same for me - I nearly gave up on it on the 10t but going another few turns on the b screw made all the difference, (hardtail btw).

Have you tried any chainline adjustments? I don't know why SRAM doesn't suffer from this, but 12-speed Shimano does seem to suffer from noise and the back-pedalling issue when in the bottom few gears. Are you able to move the chainring left a bit see if it helps?

Check rear mech hanger alignment or that mech hanger retainer screws are tight - absolutely critical with 12 Speed. Even new bikes out the box often need tweaking.

It was a bike I already had and I built it up myself. So it’s all definitely screws together ok with a torque wrench to finish.

I can’t move the chainline as it’s got an X1 Carbon GXP crank on a 73mm bottom bracket shell. I’ll tweak the b screw about a bit and see how it goes.

I think I was expecting it to be a game changer from my gx 11 speed and I’m just underwhelmed - the skipping about was annoying though. Guess it was only 3 days into riding it so maybe it’s bedding in and it just needs some fine tweaking.

The other bike is definitely not getting shimano 12 speed though - think sticking with Sram 11 speed is the way forward.

The only issues I had with Shimano 12 (admittedly XTR all round) was when I tried to use a Praxis chainring that the chain didn’t like. When I swapped to one that worked with the chain I had absolutely no issues through from about October to Feb, when I changed over to AXS.

Unless I'm missing something haven't you just explained why it isn't working properly? You are trying to combine a SRAM chainset with XT 1X12, which is well documented to not work very well. I changed over to 1X12 recently but it was clear that keeping my XX1 chainset wasn't going to work. With the whole drivetrain changed over it works perfectly.

I have Shimano 12 speed on 3 bikes now.
Shifting is superb but the longer chain lengths makes it noisy as hell when going through the rough stuff. Combine that with the 2 bikes with 8100/9100 4 pot brakes and I've never had such noisy bikes.
(All chainrings are FSA megatooth in non-boost position)
The only mechanical issue I've had was on my Solaris.. cleaned, lubed and put away after wet winter/spring riding (now hanging in my office) and the roller bearing in the clutch rusted solid. Had to wet sand the axle and swapped a bearing in from an old Zee mech and it's good again but I've no idea how water got in there in the first place.

Might have to try shortening the chain but the shifting so good as it is, I should probably just ride with earplugs.

Sram chainrings aren’t said to play well with shimano 12 speed but I’m not running a Sram chainring. I’m running a Northshore Billet chainring that has Sram direct mount figment but has shimano 12 speed profiled teeth. It plays lovely with the chain all the time - it’s at the back I’m getting some skipping about when it gets a bit mudddy.

When swapping over to Shimano 12 speed, did quite a bit of research and the sram rings don't play nicely with the shimano chains.

I'm running a OneUp chainring (as have raceface cranks) with no issues, drivetrain is super quiet, both when peddling and also from chainslap. Sram 12 speed clutches arn't the strongest and found they give up the ghost after 6 months.

IMO, 11 speed from both Sram and Shimano was really good. Ran a mix of X01 to GX with no issues, you could pull the pin from the clutch preloader and add more clutch tension. Sram 12 speed is not nearly as durable, cassettes seem softer as getting half the mileage out of them.

I found I preferred SRAM eagle.

Some mech hangars are SRAM/Shimano specific*...not that they won't work but means more fettling.
Based on that I reckon even when they aren't specific they may have bias to one or the other.

*My year of T-130

fwiw I've got full SLX 7100 minus chainset, which is a repurposed non-boost double with chainring in the outer position and it all works fine.

12 spd slx / XT on two bikes here with sunrace 11-50 cassettes. Shifting is pretty good and I don't get the skipping so generally a fan.

But both do suffer with sometimes missing the shift back from 3-4 tallest gear to an easier one, quite often not shifting on one click then going two with the next. Haven't spent much time fettling to try and solve it but do keep meaning to buy a hanger alignment tool.

Can't fault mine - best drivetrain I've used (inc M960, M970, M980, M9000, M9050 Di2).

I demoed a bike last winter with new SLX.  The bike was brand new (I was not aware of this at the time) but during the ride it sounded like a bag of spanners once it got muddy, I thought the BB was totally shot but once the grit was off it was fine again.  Was the noise from the drivechain, if it was like that every muddy ride I couldn't live with it, it was horrible.

I'm on 11spd GX myself (despite new frame, wheels and cockpit in the last year).  I can still live with 42T as use a 30T front, which is fine for most of my riding, and rarely spin out going down unless on road, it just works. The Shimano shifting was not significantly better.

Can't see me shifting to Shimano any time soon as would need a new freehub and I use Code brakes and a Reverb 1x so the cockpit set up is nice and clean.  I guess it will be GX Eagle when the current drivechain wears out.

@razorrazoo - that was the exact setup I was running before - 10-42 with a 30t chainring. My trail bike weighs about 33lbs as it has 140mm Lyriks / Code R’s etc.

Your experience of Shimano 12 speed is the same as mine so far. As mentioned above I’m going to tweak the b screw slightly and see if having it a little closer gives it a bit more chainwrap and less skipping in mud.

I’d like more range on the other bike when my frame arrives so think I’ll keep gx 11 speed and the 30t chainring and just pick up that Sunrace 10-46 they’re doing and see how that goes.

When I moved from a Shimano 2x9 to a sram GX eagle 1x12, I found that I had to set the bscrew closer than the tool advised before I got clean shifting. Weirdly their no tool adjustment advice seems to set it closer than the tool and gave a better result for me......
Not sure why this is so apart from maybe my bike is sub optimal for a 1x12 and so optimal settings don't apply. Same could be true for you.