offset= the relation of the rim mounting surface compared to center line of rim width. Example: 15x7 CJ rim. 7 inches is inside bead to inside bead, rim is 8 inches overall with a centerline at 4 inches and backspacing of 3.5. Backspacing is distance from the inner edge of the rim to the mounting surface. So that's 1/2 inch negative offset. Negative because the mounting surface is on the inside section of the centerline.
1975 CJ-6 304 T15 Dana20 30/44 3.73
1983 CJ-8 258 T5 300 30/44 3.31 Looking for full or half hardtop buy or trade
1986 CJ-7 Laredo 4.6 stroker T5 300 30/44 3.31
1986 TJ-7 Trail Jeep project in the works
2003 Inca Gold TJ Rubicon