Originally Posted by David@ApexRaceParts
The 1.472% difference in diameter is acceptable, but the 225/40/18 can also be used if you would prefer a similar overall diameter. We usually recommend the widest tires that is able to fit on a car with the particular wheel size and offset, and the 235/40/18 happens to be the widest tire that would fit on the front of your e90 LCI. The 225/40/18 will be a little bit stretched, but if you are okay with not getting the widest tire on the front, it can work.
Yes, there is sufficient space on the strut side to fit the 18x8.5" ET38 ARC-8 wheel on your e90 LCI. There is adequate clearance from the wheels and tires to the OEM struts of your car.
Would the little bit of stretch be almost negligible if it's a PSS? I like idea of having extra sidewall with 235/40 but worried that 235 PSS measure like a 245 and might rub. Do your wheel and tire recommendations take into account that I'm lowered on H&R Sport springs? I appreciate your time.