Rear derailleur at limit, chain still rubbing I gave my bike a thorough service recently by pulling it apart and cleaning/re-greasing everything. Now everything is back together and I just can't get the rear derailleur to work properly.
The H limit screw is already fully backed out and the derailleur is at its mechanical limit, but the guide pulley just doesn't move out far enough to eliminate the chain rubbing against the 2nd smallest cog.
During service the rear axle and cassette stack was removed, however I took care to measure the position of the cone nuts beforehand and they should be in the right position. The stack is also bolted together (except for the last 2 small cogs), so couldn't be a missing spacer.
What could be the cause of this?
PS: The bike was never in a crash, so I guess the hanger is not bent. In any case I have no derailleur alignment tool at hand if it were.
The model is a Simano Deore XT (2013)
If aligning the hanger doesn't work, it's not a tweaked derailleur, the guide pulley isn't slopped out, and it behaves the same with zero cable tension, the fix is then to put a spacer under the RD mounting bolt. In shops this would be a 1mm M10 axle spacer, but you can improvise with whatever.
It's unusual to need to do this on aluminum bikes, so I kind of suspect it's something else, but in a pinch the spacer may be a solution of sorts anyway.