I’m running shimano XT 1×11 on my transition scout.
The drive chain is all shimano except the chain which is a Sram pc1170. The chainset suits the rear wheel spacing 142mm.
So as soon as the bike sees mud and clag the chain suffers from chain suck from the chainset.This is worse at the top end of the the cassette to the point it tries to derail to the inside of the frame.
Has anyone else suffered the same?
Is it just the mud or is there a cure.

What chainset?

XT m8000 for 142mm rear hub

UK sourced or built in Taiwan? The UK sourced ones arent proper 1x – so have a rubbish chainline. Depending on the bottom bracket you’re using you could maybe switch around the spacers to compensate .

We’ve found the Shimano chainrings aren’t quite as good at chain retention as perhaps they should be.
We’ve been fitting Burgtec instead with huge success & little/no problems.

Cranks and chainring supplied by evans so UK sourced. 75mm BB with no spacers. To resolve it if I had spacers fitted I would have to remove them to reduce the chain line moving the chainset inboard .
In the dry it’s fine just in the mud it’s like a bag of bolts getting hung up on the bottom of the chain ring.
Could it be the Sram chain?

Hmm, I guess the best route is to go back to a standard 73mm bb with spacers and then shift it over. TBH I find that even on a ‘proper’ 1x crank its much better in the mud and grime with that spaced another 2.5 over again (so -5.5 mm from your chainline).

I only use shimano chains but they are directional and cause issues run the wrong way. No idea about sram. I
How many miles has it all done? Was it all new at the same time?

SRAM chains are bobbins. Snap at the drop of a hat. Shimano are faff. Try KMC.

Have to say 1x, I’ve never had chain suck with a combination of KMC chain and narrow wide chainring. Used to get it frequently with 2x, certainly with a SRAM chain, not sure if I ever did with KMC. Though my money’s on the chain ring and I guess chainline.

Sorry,to be clear 73mm bb (previous typo )
Sram pc1170 chain and XT 1x chainset all only about 150 dry miles since new.
I thought I take the scout out in the mud for the 1st time and it suffered from really bad chain suck as soon as it got filthy.

could it be a tight freehub..?

The chain seems to be hooked up on the chain ring even with the clutch engaged?

Chain too short?

Damascus,
Maybe that’s it. I read the instructions which said big , big plus 2 links.
I have found when I ran 1×10 on my other bikes it worked out big big plus 4 links.
I will check.

1x definitely runs better with a longer (+4) chain.

Ben – why would the source matter? All single and double chainsets use the same arms, with the chainline correction being built into the Shimano single rings. Cranks are made in Japan, so don’t see why Taiwan vs UK would make any difference?

Got 1×11 XT on one bike and 1×11 XTR on another – both with XTR chains. No chain suck issues on either, and both have been ridden in (almost exclusively) filthy Scottish conditions for months.

If chain length increase doesn’t help, I’d try alternative chains.

i’m off to check the chain over.

Ben – why would the source matter? All single and double chainsets use the same arms, with the chainline correction being built into the Shimano single rings. Cranks are made in Japan, so don’t see why Taiwan vs UK would make any difference?

The XT cranks sold in the UK are not the 1 by specific versions … there is actually a 1x specific version available. If your bike was assembled in Taiwan, they would likely have that crank rather than the 2x versions sold in the UK. I am not aware of there being 2 versions of the chainring, so I guess the 1x crank could run the same chainline as the 2x, but I don’t believe that to be the case.

No mention of suckling pig? Disappointed.

Never seen any mention of a different 1x crank – can you point me towards that? Not on Shimano dealer manual, nor their tech website?

Id like to see what evidence you have of this Ben, as i havent seen anything from Madison or Shimano on what you are saying.

XTR single and double are the same cranks with the single chainring correcting the chainline. I’ve got both and so know this to be the case (same part numbers on the arms).
Would be odd for XT to be different.

I have just read my own post title and your right no suckling pig 🙂
Bloody predictive text, the next predicted word was duckling 😀

I haven’t actually got any from the factory yet – I will be able to confirm it either way when they come in. The reason I believe they are different is from the OE ordering list – on the OE list it has way more stuff than you can buy in the shops, and they break down assemblies into their individual parts so you know what you’re ordering (useful for things like Deore brakes where there are a zillion versions made up of various series parts and only 1 is the one you buy in the shops). The 1x crankset assembly for the XT8000 lists a different crank arm part code than the 2x. That would be odd if they are the same… not to say that when they arrive I won’t be scratching my head saying ‘why are these a different code for the same cranks?’. Wouldn’t be the first time I’d been left confused by the shimano specs 😉

… I should also add that I really should have just measured the chainline! My thinking is somewhat influenced by having fitted these cranks and thought the chainline was just really wide. We run a special OE only (I think) BB on our SRAM stuff that takes the chainline all the way down to 48 or thereabouts, which is pretty much awesome. And thats on an XD cassette which should run a wider chainline than XT anyway due to the cassette position on the freehub.

Madison’s part numbers are different too. The single ring cranks are sold on their own whereas the doubles come with rings fitted – different part numbers, same crank arms.

Yes, but the part numbers I’m referring to on the OE are listed as [arms only (no rings fitted)] + [ring 1] + [ring 2] +… etc. as you don’t buy them like you do in a shop.

Like I say though, just because they gave the arm a different part code doesn’t mean it won’t show up and be the same as a 2x.

The fact that they don’t list alternative single rings points to them being the same. I understand your take n chainline, (but it is easily adjustable to go narrower), and narrower than RF’s chainline with Cinch rings (unadjustable chainline).

Yeah – we’re rethinking the RF cinch line up we supply since XT 11 came into stock – at the moment we’re tending to push people towards the Aeffect as that runs a 50 chainline (which still isn’t the best it could be – but its easily fixed up on ring #2 like a shimano crank, and the most comparable to a shimano crank in terms of weight, BB setup etc.).

Having said that – 50 vs 50.4 vs 51? About the same when in reality you need <49. 0.6/0.4mm is just messing about!

The adjustability is the key part to me. I’ve adjusted mine in. Wouldn’t like to not have that option.

I’ve no problem at all with my XT 1×11 setup, but running an old SLX crankset with Absolute Black Oval 32T and SRAM chain on a 2011 Cube Stereo. No spacers either, as press fit, so the chainline is how it came from when it was sold with a triple.

jimr80 – Member
I have just read my own post title and your right no suckling pig
Bloody predictive text, the next predicted word was duckling

Did you hear that the guy who invented predictive text died recently?

His funfair is next monkey.