The 2012 Jeep Grand Cherokee tire size depends on trim: the Laredo, AWD takes P245/70R17 108T; the Limited, 3.6L Eng VIN G, AWD takes P265/60R18 109T; the Laredo, RWD takes P245/70R17 108T; the Limited, 3.6L Eng VIN G, RWD takes P265/60R18 109T; the Limited, 5.7L Eng VIN T, RWD takes P265/60R18 109T; the Overland Summit, 3.6L Eng VIN G, AWD takes 265/50R20 107T; the Limited, 5.7L Eng VIN T, AWD takes P265/60R18 109T; the Overland Summit, 3.6L Eng VIN G, RWD takes 265/50R20 107T; the Overland Summit, 5.7L Eng VIN T, RWD takes 265/50R20 107T; the Overland, 3.6L Eng VIN G, AWD takes 265/50R20 107T; the Overland, 3.6L Eng VIN G, RWD takes 265/50R20 107T; the Overland, 5.7L Eng VIN T, AWD takes 265/50R20 107T; the Overland, 5.7L Eng VIN T, RWD takes 265/50R20 107T; the Overland Summit, 5.7L Eng VIN T, AWD takes 265/50R20 107T; the SRT-8 takes 295/45ZR20 110W, per the factory service manual.
Factory-Spec Tire Size
Varies by trim
Laredo, AWD: P245/70R17 108T
Limited, 3.6L Eng VIN G, AWD: P265/60R18 109T
Laredo, RWD: P245/70R17 108T
Limited, 3.6L Eng VIN G, RWD: P265/60R18 109T
Limited, 5.7L Eng VIN T, RWD: P265/60R18 109T
Overland Summit, 3.6L Eng VIN G, AWD: 265/50R20 107T
Limited, 5.7L Eng VIN T, AWD: P265/60R18 109T
Overland Summit, 3.6L Eng VIN G, RWD: 265/50R20 107T
Overland Summit, 5.7L Eng VIN T, RWD: 265/50R20 107T
Overland, 3.6L Eng VIN G, AWD: 265/50R20 107T
Overland, 3.6L Eng VIN G, RWD: 265/50R20 107T
Overland, 5.7L Eng VIN T, AWD: 265/50R20 107T
Overland, 5.7L Eng VIN T, RWD: 265/50R20 107T
Overland Summit, 5.7L Eng VIN T, AWD: 265/50R20 107T