[0w40X1]

I like your idea to run out tires on a wearing vehicle, and a non wearing tire aging vehicle.

When rear 9" is worn it could go to front on other vehicle (if it fits) where my 8" doesn't wear much.

I have saME car X1 s28i M sport, and rears barely get traction since 258 torque isn't split to front like the x models.

What would be alot of fun would be 9" in both vehicles all around with 255/35r18 smaller diameter 25" instead of 26", and more likely to fit.

Just keep wearing out rear of X1, and moving to non wearing car.

My idea gives you 1/2 inch more clearance for front, and 12 mm spacers on front can keep it off strut if necessary.

Front spacers might be better anyway to make track more square./

Front track is 1.1 inch more narrow than rear, and if front is too narrow cars sways at high speed.