Just back from a spin and my gears were all over the place – rode on Tues and all was spot on – nothing's being modded in between.

Running a 1×9 hardtail set up; oldish XTR shifter, XT rapid rise rear mech. Newish cable and clean outers.

Problem = won't change down (to smaller cogs), needs 2-3 'clicks' of the shifter to move 1 gear. But reasonably happy changing up (rapid rise). Inspecting the cable, it seems when changing down there's minimal movement of the cable vs changing up. Further, the shifter itself seems slack when changing down.

Have adjusted the cable and adjusters but no joy. Feels like a problem with the shifter (it is an old one) – any clues what to look for if I dismantle it?

Ta

If the shifter itself is only releasing small amounts of cable them something's stuck/sticky/etc inside. As it's old, I'd suggest really soaking it with penetrating oil and see if that helps flush it through and free it up. If that works, the relube with chain spray oir or similar (I've resurrected a couple of very old shifters that way)

Taking apart is possible BUT there are a lot of bits inside, many small and some will tend to spring out as you disassemble – not one to do if you're not mechanically confident.

thanks clubber. Did as you suggested … but what it seemed to be was the outer cable by the rear mech was too long – have shortened it a little and all's well now. Odd that it's been great for months pre today?