New 11 speed mech hitting cassette – what am I doing wrong?

I’m putting a new 11-speed drivetrain on my old hardtail. XT M8000 rear mech, GS – it’s good up to 46T at the rear – and a Sunrace 11-46 cassette.

I’ve attached the derailleur and run the cable to it; but when it gets to the lowest 2 gears the jockey wheel hits the cassette. Not great photos below, but basically when the mech body is at its default angle the jockey wheel doesn’t clear the 46T sprocket; but if the mech’s angled backwards it clears them with ease.

What am I missing here/ what am I doing wrong?

Is the b tension screw pushing against the rear of the hanger?

When there’s no tension on the mech it’s probably not going to sit right. Get the chain on there and it’ll be hunky dory (maybe)

Try with a chain. It normally needs the tension of the chain to pull it forward so it will clear the cassette.

Also play with the B tension screw.

Remove cable, cut the chain to length and fit, move the mech by hand to the extremes while (gently!) pedalling to adjust the limit screws, them fit cable, index as required and adjust b-screw as necessary.

Refer to the park tool guide as I’ve ridden single speed for 90% of the past 15 years. ;)

It used to be that the top jockey was much closer to the cage pivot. These days, the distance is greater. Having a chain of the correct length fitted will put the cage forward and allow it to clear the cassette.

You need to get the chain on and tensioned as it changes the geometry of the mech. The top jockey wheel isn’t concentric to the cage pivot point so as the cage pivots forward as the chain ‘pulls’ the cage forwards in the lower gears and the top jockey wheel is pulled down and away from the cassette.

Yeah chain needed :-)

What am I missing here

A chain. Then the b tension screw.

Move the cage into the position it will be in the lowest gear with a chain on.

Does it still hit the cassette? It probably won’t, but if it does then B tension.

That combo will definitely work. Have done 3-4000k with the same model parts (2nd cassette).

What am I missing here

A chain

:D

Great, thanks! The Shimano manual doesn’t have a huge amount of detail, and depending which installation guide you watch online, some recommend cabling first, others chain first.

Chain length should be… run chain round largest sprocket, chainring + 4-5 links, right?

I’d be careful, as I’ve found Shimano 11spd to be really particular about chain length. Go a bit longer than needed, just in case, as you can shorten the chain if need be.

I normally thread the chain through the mech while it’s in top position, loop it around the chainring, and pull to tension. Then work out visually (count links) how much you need to take off, erring on the side of caution.

Which Shimano document are you using? There’s various types and the dealer installation one is required for detailed information.

Chain length is big sprocket to big chain ring – not thru derailleur + 2 full links ie 2 outers and 2 inners. These days, most people use a quick link which counts as an outer.

It can be easier to set the limit screws without a chain but everything else needs the chain on

Which Shimano document are you using? There’s various types and the dealer installation one is required for detailed information.

Dealer manual for the rear mech, which is broadly fine, but not entirely clear – and also says chain length should be big ring to big sprocket +2 links…

You’ve probably got the answers you need above, but…

When I updated the gearing on my Shan, I needed to install a Goatlink.

It looks like you already have something similar, but is it possible a bigger one is required?

Thanks everyone for the feedback; I’ve finally had time to get back to working on the bike. Everyone who said it needs a chain, have a gold star. Measured up the chain (wrap big sprocket and chainring + 4 links), added quick link, threaded through mech. Cable length was fine; screwed the B-limit screw most of the way in and voila.

Indexing is pretty much spot on with the exception of running down the cassette (ie to higher gears) I can’t get it to drop into the second largest sprocket – all the others are fine. A bit of finetuning and it should be good to go. Also in shot (but out of focus) is the new just-fitted Ascent II dropper too

Excellent!

You might want to turn that watering can around before someone trips on the spout.

The bottom of page 17 of this manual shows where the upper jockey should sit in relation to the largest sprocket. Adjust with the B tension screw to get it to where it needs to be. Couldn’t get it to insert as a linky

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://si.shimano.com/en/pdfs/dm/RD0004/DM-RD0004-09-ENG.pdf

Shimano linky

https://si.shimano.com/en/pdfs/dm/RD0004/DM-RD0004-09-ENG.pdf

You might want to turn that watering can around before someone trips on the spout.

hehehe.. will do!

And thanks STR, will double check that; pretty sure it’s right, but always worth a final check.

The indexing adjustment in that manual is confusing af; something about ‘the chain should be just about ready to shift 2-3 when the shifter lever is released’. For now the indexing works pretty well with the bike in the stand (apart from 10th/ 40T when going down the cassette), but will take it out for a fettle and tweak

For now the indexing works pretty well with the bike in the stand (apart from 10th/ 40T when going down the cassette), but will take it out for a fettle and tweak

It’s less critical than 12 speed, but 11 still benefits from having the hangar alignment checked and your issue at one end of the cassette could be due to it being a bit bent.

It’s less critical than 12 speed, but 11 still benefits from having the hangar alignment checked and your issue at one end of the cassette could be due to it being a bit bent.

This also ^^

Albeit 12sp, I was having all sorts of shifting issues the other week – hanger ‘looked’ fine. Thought I’d give the hanger alignment tool I’ve had sitting in the bike bits box for ages a go

It was miles out of alignment and made a big differrence straightening it up

It’s less critical than 12 speed, but 11 still benefits from having the hangar alignment checked and your issue at one end of the cassette could be due to it being a bit bent.

Anything from the change to 9 onwards is all but impossible to eyeball as straight enough.
Over 30% of new bikes need a tweak these days, including your 10 grand superbike frames, and anything that comes for a service on the gears gets it looked at as a matter of course.