XT M8000 1x11 can't line up? Is this a joke?

mudge · Apr 9, 2016

Jwiffle said:
I built a sram equipped 1x11 that initially had the chain drop problem when back pedaled. Turned out the derailleur hanger was just slightly misaligned. Put the alignment tool to it, and no more chain coming off when back pedaling. Even new bikes sometimes need the derailleur hanger checked.

Makes no sense at all, given that the chain/back pedal issue occurs on the opposite side of the cassette from the derailleur. The chainline isn't affected by the derailleur at all.

Now, shifting is of course affected, but that's a whole 'nother issue

LyNx · Apr 9, 2016

Sorry, have to agree with the others who say get a spiderless crankset. To me for proper chainline you need to be running around a 47mm chainline with the Shimano 11spd or run into this issue. Fact is on 135/142 hubs, chainline absolutely blows with a 50-51mm chainline, but it does work well on a 150/157mm rear really well, perfect chainline. Will agree on how hard the shifting feels on the new 11spd compared to the previous 10spd, just setup 3 bikes with it and they all had that stiff, hard feeling, I'll be sticking to 10spd (once I switch my main ride) for a while, testing on my 2nd ride right now with XTR RD and shifter and another with Deore RD and ZEE shifter and smooth and soft as butta.

Jwiffle · Apr 9, 2016

mudge said:
Makes no sense at all, given that the chain/back pedal issue occurs on the opposite side of the cassette from the derailleur. The chainline isn't affected by the derailleur at all.

Now, shifting is of course affected, but that's a whole 'nother issue

You might think. But I'm telling you, straightening the hanger fixed the issue. Further, if you have a derailleur way out of adjustment, it'll drop when back pedaling on just about any drive train. That's experience working on bikes, not theory based on where the derailleur is located.

thecanoe · Apr 9, 2016

GH28 said:
On top of the alignment issues, the shifting is stiffer and harsher than the 10spd setups, contrary to what their claims are about it.

Has anyone else run into this and found a legitimate solution for it?

I also felt that the 11 speed XTR shifter was very stiff. My arthritic thumb was so sore after a ride that I swapped the 11 speed drivetrain for a 10 speed XT with an 11-42 10 speed cassette.

LyNx · Apr 9, 2016

He is correct, I had a bike the other day that was dropping the chain on back pedal, pulled the RD, checked the hanger, it was bent, straightened it and then no more chain dropping when back pedaling.

Jwiffle said:
I built a sram equipped 1x11 that initially had the chain drop problem when back pedaled. Turned out the derailleur hanger was just slightly misaligned. Put the alignment tool to it, and no more chain coming off when back pedaling. Even new bikes sometimes need the derailleur hanger checked.

mudge said:

Makes no sense at all, given that the chain/back pedal issue occurs on the opposite side of the cassette from the derailleur. The chainline isn't affected by the derailleur at all.

Now, shifting is of course affected, but that's a whole 'nother issue

Click to expand...

GH28 · Apr 9, 2016

I've seen the bent hanger causing the backpedaling issues before - the reason for that (I think) is that the 10spd and 11spd chains are very prone to twisting, so it can affect how the chain meshes with the other side of the cassette from the roller side.

Good suggestions here. Just to see if the chainline is indeed the issue, I may set it up with some spacers to bring it centered with the cassette just to prove the concept, then figure out a longer term equipment solution. Still a PITA. Shimano/SRAM have been making drivetrains for what, 25 years or so now? The fact that this is even an issue after this amount of time is pretty pathetic. They're not new at this.

Thanks for the input.

mudge · Apr 10, 2016

Jwiffle said:
You might think. But I'm telling you, straightening the hanger fixed the issue. Further, if you have a derailleur way out of adjustment, it'll drop when back pedaling on just about any drive train. That's experience working on bikes, not theory based on where the derailleur is located.

You can say it happened, but can explain WHY it happened? When back pedaling, the chain/cassette interaction is already done well before the chain comes off the lower edge of the cassette and routes through the derailleur. What possible force on the chain at that point in the system could cause the chain to derail from the cassette on the opposite side?

What I'm getting at here is that you may be talking about something completely coincidental, but in no way causal. If you can't explain the forces at play on the chain as it routes through the derailleur and how they cause the chain to derail at the top of the cassette, I'm not buying it. Hell, next you'll tell me the rear derailleur alignment causes chain drop at the crankset.

Jwiffle · Apr 10, 2016

mudge said:
You can say it happened, but can explain WHY it happened? When back pedaling, the chain/cassette interaction is already done well before the chain comes off the lower edge of the cassette and routes through the derailleur. What possible force on the chain at that point in the system could cause the chain to derail from the cassette on the opposite side?

What I'm getting at here is that you may be talking about something completely coincidental, but in no way causal. If you can't explain the forces at play on the chain as it routes through the derailleur and how they cause the chain to derail at the top of the cassette, I'm not buying it. Hell, next you'll tell me the rear derailleur alignment causes chain drop at the crankset.

Whatever, dude. I'm not a physicist. I'm telling you what I actually experience working on bikes every day. (Which has been backed up by others' experiences as well, as they've already shared)

But try this little experiment: shift into a low gear. Then with everything stopped, shift a gear or two higher. (Don't move pedals, just click the shifter). Then back pedal. The chain will drop down the cassette. Because the derailleur because is shifted over. A misaligned hanger causes the same issue. Because the chain is getting pulled by the derailleur when back pedaled, even though you may not think so.

Now go learn to actually work on bikes instead of theorizing.

mudge · Apr 10, 2016

Jwiffle said:
Whatever, dude. I'm not a physicist. I'm telling you what I actually experience working on bikes every day. (Which has been backed up by others' experiences as well, as they've already shared)

But try this little experiment: shift into a low gear. Then with everything stopped, shift a gear or two higher. (Don't move pedals, just click the shifter). Then back pedal. The chain will drop down the cassette. Because the derailleur because is shifted over. A misaligned hanger causes the same issue. Because the chain is getting pulled by the derailleur when back pedaled, even though you may not think so.

Now go learn to actually work on bikes instead of theorizing.

Funny, but it doesn't do that on my bike. Yeah, I just tried your experiment, didn't happen. What DID happen was that as the chain came off the bottom of the cassette, it no longer lined up with the upper pulley and thus wouldn't run through the derailleur smoothly, causing the chain to go slack between the cranks and the cassette. It did not drop down the cassettes as you suggested it would.

Jwiffle · Apr 10, 2016

mudge said:
Funny, but it doesn't do that on my bike. Yeah, I just tried your experiment, didn't happen. What DID happen was that as the chain came off the bottom of the cassette, it no longer lined up with the upper pulley and thus wouldn't run through the derailleur smoothly, causing the chain to go slack between the cranks and the cassette. It did not drop down the cassettes as you suggested it would.

And after it goes slack, it drops down the cassette.

uzurpator · Apr 10, 2016

noapathy said:
Um, no. I just demo'ed a bike with a SRAM "native 1x11" setup and had zero issues with backpedaling in any gear. As I'd heard of this issue I checked for it specifically. I'm sure some have issues, but not ALL.

I tested approximately 200 drivetrain setups before I started making chainrings and then tested some more. What is your experience on that front?

_ALL_ native* 1x11 have this issue, because all run on extreme chainlines - some of them register deflections higher then cross-chained 3x9 did.

This is done because we need to extend the cassette to the spokes, because there is no room otherwise, and on the other hand, the front the ring is not dead-center on the cassette but offset some to the outside because there is a big fat tyre in the way, and people want short stays anyways.

Anyhow.

Any chain gear will experience this issue if the cogs are not planar. The more planar distance there is, and subsequently, the higher chain angle in respect to the cog planes, the more likely it is to happen. In a well engineered drivetrain you might not notice it right away, but once wear and chain stretch accumulate, it will start happenig. The best an engineer might do is to ensure that it happens as late into the drivetrain life as possible.

Bikes with long stays will have less of this issue, bikes with short stays - more. Some hub/chain combos will experience it more, some less, on some it is going to be neglible, but essentially - it is possible to make it happen on all of them.

*with the exception of, maybe, combos of 150 hub and regular chainset

92gli · Apr 10, 2016

GH28 said:
I'm curious where your chainline aligns on the cassette then?

I just looked. My 30t ring is a race face 104 bcd on an older xt triple crank. So the ring has a little extra inward offset (2-3mm I think). The chainline lines up with the 6th or 7th cog on the cassette. I think the chain looks straightest when it's on the 7th cog.

I'm switching cranks to a sram XO with their direct mount ring later this week. Curious to see how the chainline ends up then. Right now, the distance between the inner face of my chainring and the face of the BB is 3/8" (including the one spacer on the BB).

Davide · Apr 11, 2016

GH28 said:
...

Second thing I noticed is that even with no spacers on the drive side BB, the chainring still can't center up with the cassette. It centers up with gear 7 or 8. So this is really a 2x crankset, just labeled as a 1x...gotta shim the chainring now and find longer bolts.

Alignment is a problem with 1x, and it happens with SRAM or Race Face as well, my experience is here http://forums.mtbr.com/drivetrain-s...derailleurs-cranks/garbaruk-oval-vs-race-face-chain-line-993888.html?highlight=. Although my XT/XTR derailleur/shifter work perfectly the angles at the extremes of the range are still much more than they would on a 2x.

Extent of the problem depends on your rear triangle geometry and partly, when it comes to deraillement, on adjustment of the derailleur. It is a bit of the elephant in the room for 1x ... 2x never has problems like this.

TwoTone · Apr 11, 2016

Just wait til the Eagle lands. Can't wait to read all the *****ing that'll bring.

Ogre · Apr 11, 2016

LyNx said:
Sorry, have to agree with the others who say get a spiderless crankset.

Totally agree here. Shimano makes great stuff in general, but their cranks are seriously out-of-date at this point. The direct mount cranks from SRAM or RaceFace Cinch are much lighter and more suitable for 1x use. Also, the spline mounts they offer are much nicer than chainring bolts.

Ogre · Apr 11, 2016

Davide said:
It is a bit of the elephant in the room for 1x ... 2x never has problems like this.

A very small elephant over next to the micro-pig. It's on par with figuring out which kind of front derailleur you need (high mount/ low cable, high mount/ top cable, direct mount/ top cable, etc etc) or a million other component compatibility issues you have on bikes.

I've managed to bungle through this 5 times without issue as have millions of other people.

Certain combinations of components just don't work well together. That's not exclusively a 1x thing.

GH28 · Apr 12, 2016

I've put in a couple of rides on the setup now, and while the shifting feels fine and it feels smooth when riding, the inability to do uphill starts at all in a low gear is a real problem. Pretty much a complete fail when it comes to an "all-mountain" drivetrain.

CRC is being a PITA about returns, so probably the last time I'll make a purchase from them except for small consumables. Guess I'll just run this drivetrain until it wears out and then switch over to something else, or just sell it pretty soon if I find good pricing on something that's known to work right.

As far as Shimano's stance about shimming the chainring inwards - F them. They engineered this mess and they offered no solutions when asked, so their opinions mean nothing at this point. Shimming coming up next.

Ogre · Apr 12, 2016

GH28 said:
CRC is being a PITA about returns, so probably the last time I'll make a purchase from them except for small consumables. Guess I'll just run this drivetrain until it wears out and then switch over to something else, or just sell it pretty soon if I find good pricing on something that's known to work right.

CRC is solid, but returns are a PITA, particularly since you can't get a refund on customs and pay return shipping depending on the situation. Shimano is kind of crap about returns and warrantee, they want you to go through your retailer so if it's CRC then you have to deal with mailing stuff across the pond.

Between the two it's really a mess, I just use CRC when I know exactly what I want and the savings is significant.

GH28 · Apr 12, 2016

Yep, figuring that out the hard way now. Oh well, lesson learned.

mudge · Apr 12, 2016

GH28 said:
As far as Shimano's stance about shimming the chainring inwards - F them. They engineered this mess and they offered no solutions when asked, so their opinions mean nothing at this point. Shimming coming up next.

FYI, the Wolftooth n/w ring for the M8000 reportedly moves the chainline in about 1.4mm. Don't know if that's enough to solve your problem, but it's worth considering.

I had initially looked at the Wolftooth rings to get their specs to see what's what, as I have one of their rings on my SRAM cranks and don't have any issues at all. Turns out the ring I have has a 50mm chainline spec, the M8000 stock ring is at 50.4 according to the Shimano website, and the Wolftooth ring for your crank would take it to 49, unless you're using the 36t ring. I don't know if it's a function of the particular cassette/chain I'm using, but with the 50mm chainline I don't have any issues on my bike.

Maybe that extra 1.4mm is all you need??

XT M8000 1x11 can't line up? Is this a joke?

mudge

LyNx

Jwiffle

thecanoe

LyNx

GH28

mudge

Jwiffle

mudge

Jwiffle

uzurpator

92gli

Davide

TwoTone

Ogre

Ogre

GH28

Ogre

GH28

mudge

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