Just bought a 2011 JKUR with <20k on the clock. It appears the tires weren't rotated, or at least not often enough. Also, the spare has never been on the ground. I measured the tread depth, spare is at 19/32, next best tire is at 15/32 (R/F). I plan on putting the spare on the L/R and the next best on the R/R, in order to put the new spare on the rear, and reverse direction on the next best. There is uneven wear on the tread lugs front (of the lug) to rear and want to even them up a bit to smooth out the ride. See below tread wear and (new position).
15/32 (to R/R)---------13/23 (to L/F)
14/32 (to R/F)---------11/32 (To spare)
--------------19/32 (to L/R)--------------
Does this look correct? Also, the biggest difference across the same axle will be 4/32. That won't cause diff issues, will it? After that, future rotations will be based on reversing direction, but I want to try to keep the 11/32 tire as a spare till the others catch up a bit. Then go to your typical 5 tire rotation. Thanks for any input...