'05 MCS on HSport springs, IE neg. camber plates at -2 neg. front, -1.3 rear. Currently running 7x17 w/41mm offset & 215/40x17 Hankook RS2's. Opportunity to buy a good set of used Kosei's. Will the 38mm offset and 225/50x15's work? Will I need spacers? Am thinking Toyo RA1's for DE track duty. 205/50x15's are lighter but shorter. The 225/50x15 are almost = to stock height. Will appreciate input to save me time, $ and trouble.

 

Yes, they should work fine... I ran 225/50R15 r-comps for a long time on 15x6.5 Flik Blast-C wheels (+40 offset), with Bilstein SP's and H&R springs and similar alignment settings.

 

Offhand it should be OK-

The two concerns are-

1) Will the rims at 15x7 +38 offset clear the suspension parts and rear lower trailing arm? Will the rim also clear an squarish aftermarket rear adjustable swaybar? Most times it will. Less offset means the wheel is placed closer to the outside of the car. 15" rim is a little closer to the trailing arm than in the larger 17" rim. There should not be rubbing but it there is any then a 3mm spacer would work in the rears.

2) Given your 1" suspension drop, will the 15x7 +38mm offset wheel put your tire in a position that might rub the front interior wheel well or the rear upper wheel arch plastic?

Key here is to use outer tire diameters that are 24" or less like the 215/40-17 you have now. Shorter tire height helps for more clearance. While the 225/50-15 are taller than the 205/50-15 or 225/45-15 (Hoosier A6/R6) it should still have enough clearance. Spacers will not help this problem, wheel arch trimming in the rear would.

 

Speaking from experience with those wheels and 225/50-15 Yokohama A048s, the rears may rub very slightly on the inner edge of the plastic wheel well trim. They did for me, but I may have been a little lower than you at the time. The rubbing was never audible (at least not with the Magnaflow ), but I could see little bits of plastic on the outer shoulder of the tires. It didn't hurt the tires at all, and stopped after they were about half worn out.

In front, no rubbing on the wheel well or trim, but the tires dragged very slightly on the body of the PSS9 dampers. A 5mm H&R spacer fixed that, and still didn't cause any rubbing anywhere else. The 225/45-15 Avon Tech Rs on the same type of wheel didn't rub with or without the spacer. I leave the front spacers installed all the time, using the above mentioned combos plus my stock X-lites with 205/50-16 Artic Alpins or 16x7.5 Koseis with 215/45-16s or 205/50-16s.

Scott
90SM