They should be 16x7" with a +15mm offset, which is about 4.59" of backspacing. An 8" rim with the same backspacing would stick out one inch farther. An 8" rim with an inch less backspacing (3.5") would stick out two inches farther.Roger Mac said:
So if I understand your question correctly, you want an 8" wide rim with 3.5" of backspacing.