Rigged up a bike with a Zee crank (which worked flawlessly with a Praxxis 10 speed and Shimano 10 speed cassettes on the same bike before) with an 11 speed 11-42 cassette, 11 speed chain, 11 speed slx shifter and single Gammut 32 chain ring which says it’s rated for 11 speed. On the 42 and next cog down there is a clacking noise and if you back pedal the chain falls off down onto a lower cog.
Just out of interest I tried doing the same thing on an 11 speed slx double equipped bike. On the granny chain ring it’s fine but on the 36 outer, back pedalling on the same two innermost cogs results in the same thing happening with the chain tumbling down onto cogs lower down.

I guess twisting the chain across like that on the 11 speed double system is asking for trouble but if you do it on 10 speed doubles it doesn’t derail.

I’m more interested in knowing what is going wrong with the zee crank. I can’t see how it can be a chain line issue but maybe it is, or I’m thinking there must be another compatibility issue and maybe you can only operate Shimano 11 speed with Shimano 11 speed specific single ring cranks. I’ll get onto Madison in the week and ask…but in the meantime….does anyone know what the problem is?

11 speed is wider so it does seem to happen on some set ups. Don’t pedal backwards is one solution.

It happens on most I’ve seen with a 42t. It can be a mare if your bike is loaded up, you’re in the hills and stopping and starting on techy sections in first gear. A slight back pedal and it’s derrailed, so you can’t put any power down straight away to get going as normal.

I’ve had the same happen with the 11-42 cassette on my old bike, the chain would drop onto the second sprocket when backpedelling. I think it must be chainline related as I’ve just bought a Whyte t129 with a 11-46 cassette and it doesn’t do this but it has a single ring chainset while the old bike had the single ring mounted on the outer tabs of a double chainset. It does get better once the chain has worn in a bit though.

I’ve just tried to replicate this on a 2×11, 11-40T XT setup. On the inner ring, there was no problem. On the outer ring, the chain would fall down the cassette. I checked the chain and it was at 80% of wear (i.e. needing replaced). With a new chain, it doesn’t fall down the cassette in either front ring.

Cheers Scotroutes and others.

With the Praxxis 11-40 10 speed cassette and another Gammut ring on this Zee crank the bike was bombproof.

I’ll report back on what Madison reckon.

1 x 11 does give you a terrible chain line 😐

Madison say…… this is normal.

Alker…..you’ve lined yourself up in the 1 x ranks.

Are you sure about this?

it does seem to be the norm!

Mine does this, xtr shifter, m8000 medium cage mech, m8000 11-42 cassette. Ive tried different chains, different chain rings and variants of up to about 4mm of spacers to move the chainring in further (its sat on the middle tabs of an old shimano triple). It still falls off the 42 ring when back pedalling. Sadly i have learned to live with it

If only there was some way of fitting a second chain ring on the crank to avoid these issues…

Tillydog

I think you might have something there

A third would be even better, and what if we only had seven sprockets at the back, we could widen the hub flanges for a Boost-type advantage without needing a new frame.I think we may be onto something here.

Is this connected to using 2x cranks, as I’ve not had any issues with either 3x cranks or a direct-mount crank – this is across a number of different bikes going first 1×10 (plus expander) and then 1×11.

I’d also check that your hanger is correctly positioned and you’ve the H/L screws right (I do this without the chain).

Mine does this with both of my bikes, it’s the only flaw in the otherwise excellent XT 11 speed setup.

b r

Everything was triple checked because we were trying to work out why it was doing it. We even tried spacing the chain ring in a fraction using washers. We were using a Zee single ring crank that was perfect on a 1 x 10 speed system on the same bike running with an 11/40 Praxxis cassette. You could back pedal it as much as you liked in any gear and it would not budge, and there was no hint of disquiet from the chain in any gear. We moved to a 1 x11 speed system with an 11/42 cassette and it growled a little on the two biggest cogs, and derailed when you back peddled on them. It would go half a revolution before doing that, so I guess if you were very careful you would be ok – most of the time.

I tuned out the “growling” with the B screw.

I know what growling you mean Scotsroutes- it wasn’t that…maybe clatter is a better word- I equate it with stressed chain/dodgy chain line

My Segment with a full XT 8000 drive train was the same,chain would drop down the cassette when I back peddled,fitted a One up 45T expander and a new XTR chain and it does’t do it anymore,old chain was an XT

Now for weird….. We decided to go with the potential nuisance value, made a promise not to back pedal too far, and refitted the 1 x 11 speed system to this bike. The only thing that was different was that the Gamut 32t chain ring was no longer brand new, it had had about 100 miles of vigorous thrashing with the old 10 speed chain/Praxxis cassette.

Now we cannot get the new 11 speed chain to derail when back peddling and there is no longer that clatter in the two biggest cogs on the back that there was before.

The most likely conclusion I can think of is that the chain ring needed a bedding in period!

Bicycle mechanics is easy!

my XT 1×11 setup works flawlessly. I can back pedal all day if I want and it still doesn’t come off the 42t. I didn’t change any spacers etc moving from 2×10 to 1×11 and chainline looks okay. Luck of the draw?

How long are your chainstays? There’s a school of thought that it’s a problem when they are short.

the bike concerned was a Kona Process

the bike rigged up with the double was an Onza Jackpot…..they say it’s a single ring only frame but it works fine with a front mech provided you fit a cable anchor point band

I’ve fiddled with my XT M800 11-42 plenty and it still falls off the top cogs if I back pedal. It’s always at the same tooth in the pattern. It would seem it’s the tooth that helps the up-shift which knocks it down too. I wonder if it’s not so much the chainline but the cassette? A couple of mate have found changing the chainring to a non-shimano one helps so I guess it depends on the bike and setup quite a bit.

I can back pedal all day if I want and it still doesn’t come off the 42t.

Weird 😕