I have a 2015 Genesis CDA as a ‘gravel’ bike. I’m toying with the idea of getting a second set wheels for the road which are lighter and take thinner tyres which I can interchange with the existing wheelset.

Questions are around compatibility. The existing wheels use Deore / M475 hubs which are MTB size (135mm). My existing set up is 8 speed (Claris) but I may upgrade to a 10 speed group at some point (I know the hubs will not take a road 11 speeds cassette). When looking at new wheels, are road hubs 135mm or am I going to have to be careful to find a wheelset with compatible hubs (135mm / 8/9/10 speed driver body)?

Road is 130, mtb 135.

Get a set built for you if it’s a concern.
I’ve built a few sets for friends using mtb disc hubs and road rims, most for disc braked CX or touring/training bikes.

Thanks, that helps prevent me from making an accidental purchase.

Assume a 10 speed road group will still work fine on the existing hubs (I know I can’t go 11 speed)?

Yeah, should be pretty much plug and play. Might be best buying a complete shifter/mech/cassette bundle to guarantee compatibility. Or at least the same generation stuff.

FWIW the latest generation road disc wheels are now 135mm OLN as well. If you can get a pair of those it’ll be 11 speed and disc, so you can use 10 speed OR 11 speed road stuff.

Very helpful, thanks ghostlymachine.