I am currently building up a new hardtail and the final piece i need to fit is the chain. The bike has a 2×10 setup with a medium cage rear mech. I’ve bought a sram pc 1091r hollow pin chain, is it a case of just fitting the chain or will i need to shorten it?

big – big + 2 links.

The usual way is to fit the chain to large and large (without going thru the mech) and add 2 rivets (1 complete link).
This works with a hardtail.
Use same technique with a full-suss, but with the suspension set at the point of max chainlength (which may not be at an end position).

PaulD

Thanks Paul

And don’t forget to allow for chain device, if you have one.