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Admittedly, I know squat about tire/rim fitment, but I have run in to an issue.

-I bought new rims for the car, they're 18x8.5(outside) and 7.5(inside)
- Proper tires for these guys are 215/40

This set up will fin nicely under the wheel wells without needing to roll the fenders. BUT, it's damn near touching the springs on the inside of the rim and tire.

Having never run in to this issue, I'd imagine I need some kind of spacers to change the offset. I've found 15,25,and 30mm spacers to be the most common.

If I add say, the 25 in the front, and 30 in the back, I will need to roll the fender and or get flares/some kind of widebody. I can roll the fenders but do not want to allocate $ for widebody stuff.

Can I get away with a skinnier tire? If so, can anyone do the math on the spacer used vs tire sizes? I don't want the "stretched VDUB" look, but if I can get away with using a tire thats 7.5" at the least, and able to fit with the spacer, i'd like to do so.

I really don't know what the stock offsets are, the rim is an ADR M-Sport, 4x114.3. The car is a 1990 240sx.