Derailleur having trouble shifting to largest rear sprocket.

JamesHavill

I have an XT RD-M8000 1x11 full drive train with 11-42 XT cassette
The problem is that i can get it to shift into the largest sprocket but it is very hard to and jumps down most times. My limit screws are not making contact with anything, so it should be able to shift up. The top pulley is half inline with the 42t and 37t and i cant allign it any better using limit screws or b screws. When i try to adjust it by using the barrel adjuster, it can shift up alot easier but then has trouble downshifting. The cable tension is very tight. Just to clarify it can shift up but has trouble staying there or else will not go up at all.

ed1973

Hi
Did you convert it into a 1x11? I only ask as I did the same with mine (but to 1x10) and I needed to get a hanger extender. I bought a goatlink, but you can get cheaper copies from eBay but a word of warning, I bought a cheap version first and it didn’t fit my hanger as MTB hangers are different from road bikes. Anyway as soon as I put this on my shifting worked like a charm and I didn’t need to mess about with b-screw much.

The Rookie

It does sound like the L-screw is impeding it, can you push it further towards the spoke by hand?

Unless you have a whacky frame (hanger location) and wheel combo I've never heard of a mech doing as you describe.

By the way I think you have your terminology out (or it makes even less sense), shifting 'up' is up (numerically) through the gears towards the smallest sprocket, shifting down is towards the largest sprocket

JamesHavill

Ed1973 wrote:

Hi
Did you convert it into a 1x11? I only ask as I did the same with mine (but to 1x10) and I needed to get a hanger extender. I bought a goatlink, but you can get cheaper copies from eBay but a word of warning, I bought a cheap version first and it didn’t fit my hanger as MTB hangers are different from road bikes. Anyway as soon as I put this on my shifting worked like a charm and I didn’t need to mess about with b-screw much.

Nope i did not convert it, it has the stock drivetrain used to work fine until a muddy enduro race. I cant remember the name but most shimano derailleurs come with a goatlink type piece already attached and most bikes have then unless the hanger already has an extension. I may try swap the spacer around to be on other side of the shimano goatlink thing so it will push the derailleur further towards the wheel so it should be able to align better and be able to make the shift. Thanks

JamesHavill

The Rookie wrote:

It does sound like the L-screw is impeding it, can you push it further towards the spoke by hand?

Unless you have a whacky frame (hanger location) and wheel combo I've never heard of a mech doing as you describe.

By the way I think you have your terminology out (or it makes even less sense), shifting 'up' is up (numerically) through the gears towards the smallest sprocket, shifting down is towards the largest sprocket

Nope the wheels, frame, hanger, shifter and cassette are all stock as a rock on my giant reign. The screw is not making contact so it wont be impending it. I can push it up a tiny bit but cable tension is as tight as i can get it. Thanks

JBA

JamesHavill wrote:

I may try swap the spacer around to be on other side of the shimano goatlink thing so it will push the derailleur further towards the wheel so it should be able to align better and be able to make the shift. Thanks

Why do that?
If the gearing worked fine before the muddy race the spacer is in the correct place.

Suggest you disconnect the gear cable from the mech and do a complete gear index. Plenty of guides on the web/YouTube.
If you have no adjustment left on the barrel adjuster it is possible that the gear cable has slipped a bit.

cobba

JamesHavill wrote:

I cant remember the name but most shimano derailleurs come with a goatlink type piece already attached and most bikes have then unless the hanger already has an extension. I may try swap the spacer around to be on other side of the shimano goatlink thing so it will push the derailleur further towards the wheel so it should be able to align better and be able to make the shift. Thanks

Shimano calls this 'goatlink type piece' a bracket axle unit, it's also commonly known as a b-link.

The bracket axle unit can rotate clockwise on the derailleur hanger if knocked, if this happens, you will need to turn it anticlockwise to the position where it is supposed to be. If it's been knocked out of position, it can affect the shifting.

Page 8 of the Shimano dealer manual shows what I'm talking about:
http://si.shimano.com/#/en/DM/RD0004

JW599

JamesHavill wrote:

The cable tension is very tight. Just to clarify it can shift up but has trouble staying there or else will not go up at all.

I had this problem, cable tension was too tight, there was not enough slack to make the full range of movement from the shifter.

Can you get to the biggest sprocket by releasing the cable from the pinch bolt and pushing the rear mech by hand?

The Rookie

Either as cobba describes or maybe there is a lump of dried mud or similar inside the paralellogram acting as an early Low stop.

jw599 you seem to have missed that when he says 'up' he means 'down' to the biggest sprocket.