Hi all.

Just fitted new 42t XT cassette, mech, chain and shifter and all works fine apart from when back pedalling in the 42 the chain lifts and drops to the 37.

I am using old XT triple with Race Face 32t n/w

I have tried 5 – 0mm of bb spacers on drive side and it still does it. Anybody else had this problem or know how to solve it.

Thanks

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…

http://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 1×10 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 1×10 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

A little sceptical that the entire drive train is designed around a virtually unavailable spacing and that with a bb spacer you can’t get the line right, even on a 73mm shell you should have some adjustments available.

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??