[Closed] Shimano Xt M8000 Chainline Issues

Have you played about with the B screw? The setup can be sensitive to this.

Erm......don't back pedal?

Seriously.

Erm......don't back pedal?

I wasn't expecting it to take a whole 5 minutes for somebody to suggest this 🙂

The inability to back pedal in lowest gear isn't the issue, its more the overall chain line of the xt cassette and whether or not different cranks etc make a difference.

b screw makes no difference.

So...gears work fine otherwise?

Overall width of XT 11 spd is the same as XTR 11 and Sram 11.

Hanger straight?

Chain too long?

Frame out of line?

Chainline should be good on the triple in the middle position, but you could fit 2mm c/ring spacers between the spider and ring. Ditching a BB spacer (as you tried) would have a similar chainlink effect but with an undesirable effect on pedal position - like riding a poorly aligned frame.

Have you checked the above?

What hub is it on?

A few stories of xx1 doing this.
Really wide cassettes + shortish stays=shitty chainline.

Found the same issue on 10 and 11, sorted it self out on the 10 once it was worn in a bit. If you want to adjust the chainline get some I.D chainring spacers...

www.ison-distribution.com/english/product.php?part=CRIDSD06

Try a SRAM chain. Shimano chains do not work for me. I had this issue with 1x10 recently.

Brand new XT chain, brand new SLX 11-36 cassette and 32T Race Face N/W chain ring and brand new Zee mech. It would not back pedal in 1st. By chance I had just removed a SRAM chain from another bike and slung it on. It worked perfectly. Put the Shimano back on... wouldn't work. Set up a brand new SRAM chain the same length and it worked.

Pro2 (non evo) hub, new mech hanger and frame is straight. Agreed with bb spacers, don't want my crank way over to the left.

I recon I could try loosing a link from the chain will try to get some chain ring spacers tomorrow.

Cheers.

Chain line on big (40+) cogs is wrong. It needs to be 2.5mm or so farther inboard. Unfortunately no-one in drivetrain-land has noticed this 🙁 Its the same on SRAM or Shimano. Pyga noticed it but their solution is a 5mm offset wheel & back end. Great to start but a real pain when you trash that wheel. I would definitely give the the switch of 1 spacer from your drive side BB to non-drive a try, you'll probably not notice especially if an SPD user (you can adjust your cleats a bit to compensate. This will help with noise, wear and most other things.

One of the side effects of the poor chainline is back-pedalling basically doesn't work.

I'm running a SRAM chain and can't say I've noticed this?

What I am aware of tho is just how bloody sensative the shifters are, and when shifting down one gear at a time somewhere in the middle of the cassette it rolls and then engages with a clunk, I've tried all sorts but it's reluctant to stop. I'll wait and see if it meshes together a bit better over the next week.

Bit of a long shot but is the chain on the right way round, some Shimano are directional?

Squoglybob, what sram chain are you using I may swap the Ultegra 6800 for one (mine is on the right way, I think lol)
I've the same problem as the op, rides fine in all gear, pedal back and it chucks the chain down three cogs, if you drop it down one from 42 it's fine.
Off to the Apls on Friday and could do without the hassle but hopefully I wine need the 42 much.

I have the same problem with a kmc chain. Had it in the biggest 2 cogs. I removed a spacer on the bb and now just have the problem on the 42. Going to try some spacers

So ive spaced my chainring in by 3.8 ml and still have the same problem in 42. Has anyone had this issue and successully solved it? Thinking of trying a sram chain next

When you spin the cranks backwards does the jockey wheel mot meet the chain as it should? You can tell this by the clinking sound the jockey wheel makes as the chain is fed through it. It might be that the hanger is bent slightly which is along the derailleur point not quite slightly forwards

Does this make sense?

The chain / jockey wheel interface seems totally fine. The chain is falling off the top of the 42t cog. Its all quiet and non clicky, and totally fine in all the other gears

Is the upper limit screw ever so slightly screwed in too much, preventing the derailleur moving fractions of a mm towards the wheel? Also check the cable tension when if you unscrew. Start by a quarter of turns on the limit screw and the cable barrel

Thanks edward. Tried that. And also similar process with the b screw. But will give it another go. Failing that i am going to either try a tiny bit more spacing and / or a different chain

I'll have a look in the morning which SRAM chain it is that I've got on mine, a bit late if you are off to the Alps tmrw "sorry" just seen this, but it may help others.

Saying that mines clunking as it engages, in gear it's fine, say for instance I lift off and manoeuvre about on the bike then get back on the pedals it engages with a thwack as though it's half jumped out of gear. It's beginning to really piss me off now as the next thing will be snapped chain.

Just had a look at my invoice it's a SRAM 1170 11 Speed 114 link.

I'm having exactly the same issue, and I'm not even running a bottom bracket spacer! I don't really have the chainstay clearance to move the chainring any further inboard, don't know what to do next!

What chain are you using ben?

Same thing happens on my xt 40t cassette. I'm using a xtr rear mech and the previous gen xtr chainset running a single ring. I reckon much of my issue is the chain is at such an angle it rubs against the ethirteen chain guide (thick thin chain rings are great until your chain drops off) so pedalling backwards causes it to drop down a few cogs. In reality riding it I did not have any issues or find this to be a problem at all.

Ride your bike mate is my advice. It certainly shifts a damn site better than my 10speed set up ever did!

nosedive- My setup is a superstar nw ring on slx tripple cranks (middle position), xt chain, xt rear mech and xt 11-40 cassette. Tbh its not unbearable, just irritating when trying to get going on a steep hill.

Same problems here. New full M8000 set up with the Ultegra chain and short (425mm) chainstays. Pretty frustrating! I'm gonna try and move the upper limit screw in a touch and swap the BB spacer to the non-drive as suggested above.

Had exactly the same issue on my Bandit,11-42 xt cassette, 34t oval ring with spacers,kept dropping off the top cog. Removed the drive side BB spacer, still the same. Switched from a KMC chain to a SRAM 1170 and now as sweet as a nut.

So, it turns out my BB spacer was already on the non-drive side. I tried fiddling with the limits and cable tension to no avail. I guess a SRAM chain is next then!

It seems a bit of a shame that brand new XT on a new frame isn't compatible. I should really go back to SRAM.

Longshot, have you made sure the NW is in place of the middle ring?

Only say this as I just rebuilt my Hardtail with 1x10 and made this error, took me a couple of minutes to figure why the chain line was so bad.

Had this on mine, short chainstay 29er, m8000 cranks, one up 30t ring, m8000 11-40 cassette and xt mech. Seems to be better after i spaced the ring towards the frame with the the shims that came with the ring. This did not immediately solve it but a play with the b tension seems to have helped.

This is all in the work stand not tried it properly yet...

Update - changed from a kmc to sram 1130 chain and its much better. Not perfect but i can back pedal 3 full revolutions before it falls off. Should be fine for riding and i think it will get better as it beds in. Sram chain has a better split link and cheaper too

Has any had the same issues as above with a new 11 speed XT cranks fitted to the set up or is it mainly to non matching cranks?

I've just got the full group set from Bike Treks ready to build a SC solo up & now having night mares !!

I'm experiencing similar problems when back pedalling in the 2 largest cogs (11-42) with a 38t zee chainset.
Ive spent a good few hours trying to get it right today worried about riding it tomorrow but everything else about the setup works fine so I'm just gonna ride it and see how it goes. Might order the Sram chain and the front ring spacers

My mate is having trouble on his 5 and lbs said the system is designed around the 148 hub spacing not the 142 he has, not sure if this is true or not tbh

and lbs said the system is designed around the 148 hub spacing not the 142

I never managed to solve this problem. Happens with or without chainring spacers. I have decided to ignore it and pretend it is fine

It's not a 148/142 thing.(they do a chainset specific for 148 with an even wider chainline). Mine does it. A bit annoying but only happens in practice when you're stopped and chatting to mates and back pedal a bit. Never been an issue actually riding! My advice would be just get out and ride...Fixes everything!

I thought this was just a known thing and people just put up with it?

It's hardly a real problem is it??

It's hardly a real problem is it??

I also remember reading somewhere that this can improve once you've put a few miles on the chain, as it will have a bit more lateral flexibility once used a bit.

I have just built up a 1 x 11 setup using SRAM 10-42 cassette, SRAM PC-X1 chain, superstar 30t chainring on SLX double chainset, M8000 mech and shifter. Haven't ridden it yet, but can back pedal forever with no dropping off the 42t.

The 30t chainring has built in spacers (2mm I think) which probably helps...

I have recently gone 1x11 too and am having chainline issues . I am using the new xt 8000 1x chainset and my chainline is worse than my friend who used his existing XT chainset , we are both using 32T Absolute black oval chainrings . I was wondering if the Shimano casette which has the 32 sprocket dished gives a different chainline to a Sram casette.Anyway my once used Shimano XT chainset and Absolute Black chainring is going up for sale this week and I am going to use my old XT chainset as it appears to give better chainline .

XT8000 2x11 Boost here and having no problems.

Ramsey Neil - just add some chainring spacers. Depth req'd will depend on chainring used. Wheels Mfg do various depths. Better than losing money on a nice chainset and chainring.

Thanks for the tip sillyoldman but I don't expect to lose any money as I got the chainset at trade price . I am pissed off however that the dedicated XT 1x chainset gives a worse chainline than "bodging it" by converting a double to run as a single .

Pivot Mach 6, 1x11 XT M8000 ultegra chain. same problem.

If you put your bike on the stand and pedal back slowly you should notice that it drops on the shift ramps of the cassette.

Its got better as the chain has worn, but IMO its just poor design on the crank. Chainline on mine is straightest when in 8th gear, should be straightest in 6th. I'll try a different chain next time, hasnt really been an issue as I dont tend to back pedal. 🙂

Ramsey Neil - have you tried it with the XT ring? Any better?

Replacing SRAM chain fixed this problem for me. Also moved the spacer from the drive side. 2012 SC Tallboy LTc. New m8000, full group, 2x cranks. No backpedal problem with big or small chainring anymore. Thanks all on this thread!

Ramsey Neil - just add some chainring spacers. Depth req'd will depend on chainring used. Wheels Mfg do various depths. Better than losing money on a nice chainset and chainring.

On the M8000 crankset the chainring bolts to the outside of the spider so spacing it would make the chainline worse not better .

Ramsey Neil - have you tried it with the XT ring? Any better?

I don't have an xt chainring as the chainset comes without one .

I wouldn't say it's necessarily the chainset. I've just built a 1x11 on my santa cruz using XT for the back end with raceface aeffect cranks and a hope bottom bracket and a 28t chairing and I'm having the same problem. 😕

Ramsay Neil - the chainring doesn't bolt to the outside of the spider - I have one. It's also pretty clear from pictures that it mounts to the inside of the spider. I used spacers on mine to alter the chainline.

Turbo1397 - RF uses the widest chainline out of all the options out there (except Boost specific jobs).

@sillyoldman.. what would my options be?

Worth looking at alternative chainring brands - some make a point of "correcting" chainlines. I find around 48mm works best for reference. RF is 51mm.

See http://www.wolftoothcomponents.com/collections/chainrings/products/direct-mount-race-face-cinch for an option.

If you've got a threaded BB, you can take the cheaper route of moving a BB spacer from DS to ND, but then your pedals are offset to the ND side... Guess you could adjust cleats to correct.

Sillyoldman you are correct , I may try some spacers.

Turbo1397 have you adjusted the spacers on the cranks? I think they come at their widest setting out of the box. You can pull them in to 50 using the spacers on the cranks.

Also Shimano now supply BBs with variable sized spacers which allows a little more fine tuning.

I'm using a threaded hope bottom bracket.. my LBS has assembled it.. It looks like there's a spacer in there..

The cranks have spacers too (incase you didnt know).

Going to look into this today.. so what is causing the chain line issues, will it be the cranks. As I'm only running XT stuff at the back would it make any difference if I ran a sram rear cassette?

It is your chain line.

You can measure the chain line of your bike (google how) and you'll find that it will likely be around about 46mm. Depending on if you run a 3x, 2x, 1x crank, the crank will offer a different central placement of the front chain ring in relation to your rear cassette. Some manufacturers do state their chain line on cranks, which is handy but you still need to calculate the rear cassette chain line and then align the two.

The goal is to have the front chain ring align to the centre of the rear cassette (you can't accurately eye ball this, so measuring is required). If you get it bang on then it's sweet shifting, back pedalling nirvana, if you get it really close you'll be good, not close enough and you'll have exactly the same result that folk are referring to here.

Shimano make their new 1x cranks with a 51mm chain line (i recall) which is plain useless. Some NW chain rings have 2.5mm spacers fitted. If you then offset one of the spacers on your BB, or the only spacer on 73mm BB shells (don't remove them) to the non drive side, you will gain 2.5mm (5mm with the ring) towards your ideal chain line.

Note, the B screw needs to be backed off a lot, way more than you might suspect but it does/ will work out, regardless of the branded chain being used.

😀

Cheers binno. I removed the spacer on the drive side and it is better.. not perfect, but better. I'm going to ride it a bit and see how it is.. as everything I new.. chain and all.

As I'm only running XT stuff at the back would it make any difference if I ran a sram rear cassette

Yes, but not so much I would bin a Shimano cassette/Freehub just for the slightly better chainline. I would to get the 10T cog though 😉

Sram Chainline is 48mm, Shimano 50mm, Raceface 51mm, and a lot of aftermarket ring makers go for 49mm.

They are all a compromise. Some bikes require a chainline of 50+ to work with a 34T+ ring size, hence Shimano and RF going for 50 and 51. No point in a better chainline if it doesn't fit. I saw a Cotic Soul today with a 34T XT set up which didn't have much room between the ring and the DS chainstay.

Shimano's approach means that it'll fit anything (within reason) and can be optimised using chainring spacers where appropriate/possible.

Is a simple fix for all the above to just use the middle chainring position on a triple chainset - or is it that I'm still on a 26er 😉

Not really - middle ring is only a 50mm chainline which isnt helping much and is wider than SRAM 1x (Its actually the same 49mm as SRAM 3x cranks middle too). On new XT cranks though if they fit together then a middle ring on a triple combined with the 11 spd offset ring would be an improvement. The simplest current solution for the best chainline you can get would be SRAM cranks and 10 spd or XD cassette (rather than shimano 11) or other cranks with a 49 or less chainline ring installed, and a 10spd or XD cassette.

I had high hopes that the new XT single cranks would address this with a shorter axel length or offset chain ring tabs. Fingers crossed it will happen in the not to distant future.

Just incase you mis-read my original comment, the chain line specified by the manufacturers is not the actual chain line you require in order to have the front ring aligned to the centre of the rear cassette. Which is what you're ideally looking for.

So yes, in my view, with outboard style Bottom Bracket cranks, a converted triple is still the best solution. I very much doubt anyone will tell the difference by having the crank offset by a single 2.5mm spacer, which is the best solution when running a triple. If you're on a double / single ring crank, then it's the single spacer and an offset chain ring (iE: 30T Race face NW / 32T Absolute Black with built in bolt spacers) that you need to use. Although you could also use longer chain ring bolts to shim a regular chain ring inboard.

IMO it's not just a case of getting super smooth and quiet gear changes from every cog, it's also about drive train efficiency and reducing rapid wear by crossing the chain further than intended.

I do love a perfect chain line.

So how does a rf aeffect single ring work with a XT x11 boost hub. If the optimum boost chain line is 52mm, then a 51mm rf ring seems to be ok. But if I go for a absolute black cinch ring, is this dished to move the chainline back to 49mm, so maybe not the best solution?

Dont confuse official and optimum. Official SRAM boost chainline is 52, optimum would be in the 47-48 region - so if your bike fits it then the 49mm option is a good one. Its what I would run on a boost frame.

So by that rationale if you are fitting Shimano XT M8000 1x11 to a boost rear end then you would be better off using the standard chainset not the one that's meant for the 148 rear end . I'm confused .

Anyone care to comment on the spacing at the front chainring using a PF30 BB (giant anthem). Is it the same as an HT outboard BB?

I thought the anthem was a pf82?

So by that rationale if you are fitting Shimano XT M8000 1x11 to a boost rear end then you would be better off using the standard chainset not the one that's meant for the 148 rear end . I'm confused .

Yep. Basically as covered on another thread current 1x chainline is derived from 3x chainlines, which were set based on factors other than hitting the middle of the cassette, and so [i]don't actually[/i] hit the middle of the cassette. For this reason 1x chainlines are all a bit rubbish as they are too far out now that we really do want to hit the middle of the cassette for sure. Add to that shimano 11 speed runs a cassette with a narrower chainline again and it gets even worse.

In essence a 3x Boost chainline would be 52. A 1x Boost chainline should be 49 (ish) but no-one makes a real 1x chainline for anything, although some of the aftermarket ring makers are making rings to get close. However you can use a non-boost set up to get a pretty good approximation to what a boost chainline should be on a 1x.

EDIT: I should point out that a boost chainline should be more like 47, but 49 is better than nothing.

Ideally measure the chain line with the cranks you intend to buy, fitted to a frame with the same BB standard.

Use callipers to make the measurements:

1. Measure the width of the seat tube inline with the front chainring. Divide by 1/2 and note the measurement.
2. Measure from the centre of the teeth on the front chainring (either the middle or fitted single chainring) to the outside edge of the seat tube. Keep this measurement inline and level with your original seat post measurement, taken along the the top of the chain ring.
3. Minus the measurement noted from Step 1, from your measurement made in Step 2. This will give you the current chain line position of the front ring.

The principle is the same for the rear hub, only more complicated in requiring a measurement for the width of the cassette fitted.

1. Total outside axel length hub width divided by 2.
2. Note the inside measurement of your drive side dropout to your outer lock ring.
3. Measure or google the width of your cassette and divide by 2.
4. Add Step 2 + Step 3 measurements and minus this total from your measurement for Step 1.
5. Adjust your front chain ring placement to match the chain lone number you end up with in Step 4.

Measure twice to be sure 😀

Works on any bike, single speed, 5, 9, 11 gears etc... it's the same process regardless. Get it bob on and you'll be in clean shift, long life drive train bliss.

Blimey! I just put the cassette on my wheel, took all my old 9 speed rings off my SLX crank and stuck a 34t NW Ring on the inside of the spider.

Works a treat 🙂