I’m on holiday and have killed my xt 10 speed rear mech. No chance of getting new mech here. A work around is to use a top spare 10 speed pulley in place of the shagged lower one. Will it / I die? Seems to run ok. Only needs to survive another 3 days.

It’s fine. Carry on. Only difference is a bit of float.

You could try eliminating the float by using the bearing shields from the dead jockey wheel.

I have done this before. I would only do it again as a temporary fix, as the additional sideways float in that pulley allowed the chain to rub the derailleur cage. Mine eventually wore through, then the chain caught it and ripped the mech off. This was an XT 9spd long cage.

Cool. Thanks. Will carry on.

Not had any problems on mine, and find the ceramic bushes seem to last far longer than the cartridges in the correct ones.