FYI:
I have 18x9s on all 4 corners and I run 275s UP FRONT and 295s out back.
I couldn't imagine having a 275 on a 10.5 wheel.
10.5s need AT LEAST a 295. 315s look bitchin though. You could even fit a 335 if you really wanted to!
Bottomline is, If you are only installing 275s, then just go with a 9" wheel.