Essentially yes, if the offset remains the same and all you are doing is increasing the width of the wheel, the inner and outer location of the wheel edge/lip will increase the same amount.The center of the tire doesn’t move in or out, it stays in the same spot. Going from 9” wide wheel to 10” wide, same offset, would “let out” the tire some- perhaps about .4” (10mm) so only 5mm “wider” each side for the tire. Was this what you were getting at?
Going from a 9" wide, -12 offset to a 10" wide, -12 offset will cause the outer lip of the wheel to stick out 1/2" (13mm) more, and the inner lip to come in 1/2" (13mm) closer to the strut/shock.
That remains true regardless of the width change. Going up a to 12" wide wheel from a 9" wide wheel will increase the poke by 1.5" and the inner clearance from the strut/shock will be 1.5" less.







