I upgraded from a 9 speed setup to a 10 speed setup on my hardtail this weekend. I read that the 10 speed cassette needed a 1mm spacer on the backside but when I put the spacer on there didn't to be adequate room to fit the cassette and get the lock ring threaded in. I pulled the spacer and it went together fine but seems close to the spokes (but not touching or rubbing). Hub is a WTB SpeedDisc XC and the cassette is a HG-50-10 11-36T. Any insight?

You don't need a spacer on a mtn bike hub.

oh, ok great thank you - been a roadie for a while but my first MTB