Do you mean there is 5-10mm of clearance inside? 50-55 offset pushes wheel out 5-10mm.
On my FK8 I ran 255/40R18 on 9.5x18 +50 Weds.
" Compared to your existing wheel, this new wheel will have an inner rim which is 3.6mm further away from the suspension strut. The outer rim will poke out...