I went 1×9 on a 10 year old xtr rear mech – so no clutch – just bought new cassette – 12 to 36, new chain and a thick thin Hope chain wheel. Total cost 70 quid.
Had zero problems so far. No dropped chain, and I’m doing a lot of jumping. Love the simplicity of it all. Strangely liberating not having to think about shifting front rings. Simplifies the riding experience.
Def need to be fitter for the big hills – no hiding on the granny ring.
Without doubt best thing I’ve done since I got a single speed road bike.