31/10.50 do make a difference to the 30/9.50's. Doesn't sound like much, but side by side, you can tell..Good luck.
Nothing to it but to do it.
SIMPLE AS THAT.
'04 TJ RUBICON, 4.0l auto
2"BDS coils, Rubicon express shocks, 33/12.50/15 Dick Cepek Mud Country tires yellowed out, on Black steel D's.