So you're getting larger tires? Because the Rubicon already has mud terrain tires on it.
Like they said, the AEV ProCal is a great tool...you can adjust your speedo for the larger tires and turn the TPMS sensor light off so it doesn't annoy you. Mine has paid for itself multiple times already.
'92 YJ - heavily modded
'96 ZJ - heavily modded
'05 KJ CRD Limited - 370 lb./ft. from a 4-cylinder and trail ready. Pure awesomeness.
'11 Mango Tango JKU Sport - Mods
'12 Dozer JKU Sport S - 6-speed - ACE rock rails - Max Tow package - Daystar spacers - 285/70 Cooper AT3s