A bit of advice please…

The bike is a 2015 Specialized Crave XC 29er HT

I want to go with a single crank,converting from a SRAM (GXP BB)2×10 SRAM S-1255, 2pc 10-speed crank which i would replace probably with a Shimano XT

Already fitted is a XT rear derailleur and a SRAM PG 1030, 10-speed, 11-36 cassette which i would like to retain.

Is it as simple as just replacing crank and removing front mech,cable and left hand shifter??

and would i need to shorten chain?

Cheers guys

You can most likely keep the cranks, though I’m not 100% on those particular ones. You need to check the BCD -bolt circle diameter. But the new ring will most likely be a direct replacement.

Get a narrow wide chainring, bolt it on and shorten the chain accordingly.

Chainline can often be optimised by spacing the bottom bracket cups a little, sometimes even with shims behind the chainring.