wont drop onto the 10 speed cog, cable slack limiting screw backed off anything else I should check?

Sure it is the right screw? B-tension is the middle one

Ignore – half cut and read XT, not X1 😳

The limit screw has to be set so that the top jockey centre line is just past the 10t sprocket centre line which is unlike any other mech I’ve used before. The SRAM instructions will give more detail. The other issues are that the spring is pretty weak so it is worth giving everything a good clean out and relube if it is pretty well used

As above have the bottom stops so that the jockey wheels are past the 10t cog when you have pulled the mech over, the weak spring means it never actually gets this far in reality but it means you can get enough tension in the cable. Also slackening the b screw seemed to help up to a point. Had this on my friends bike and just sorted it for him. Glad I am still ten speed seems alot easier!

Hi there, had this problem myself last year, make sure you clean out all crap (airline good for this) especially the spring as the coils are very tight, then lube it all up regularly, the thing that seems to have stopped it happening again though is to make sure you leave it in 10th cog whenever left for long periods!