Originally Posted by Steve Hellums
What is the biggest 18" tire you can run on the front with the car lowered? I have a friend that just put his OEM 225/40/18 on a 8.5 wheel and I think they are too narrow for that size wheel. I was looking at going to a 235/40 or a 245/40, 235's are only .3" taller and the 245's are .6 taller. Anybody got an opinion here? Also I'm in the market for a couple Michelin PS2's in the sizes above if anyone has a pair they are willing to part with. I'm not getting what I'm looking for out of my 255/35/19's so I think I'm just going to have them mounted back on my OEM's when my new wheels come in and just leave the 225/40/18's on the front OEM rims and get another pair, but bigger for the new wheels.
There's a lot of variables in your question... The OEM wheel, or your new wheels ? And how much have you lowered the car from OEM spec ? What's the offset of your new wheels ? These are very key to answering your question...
There are three clearance issues to deal with on the front wheels / tires (1) the upper "A" frame bolt that MMZ mentioned. This is the most critical because it can't be changed (cheaply) and if you mount a tire that is too wide on a small offset wheel, the bolt will slice through the inside shoulder of the tire before you drive out of the shop. But, this clearance will always remain constant +/- a few mm when the tire flexes and the wheel turns. (2) The inside fender well which has a knife edge and retaining bolts for the wheel well liners that protrude into the well. This is a variable because of how much you lowered the car and what the offset of your new wheels are. The compression of the front suspension during turning and braking will vary the distance between these. So if you're sitting nice and pretty in a parking lot and you have a few mm clearance, that clearance may not be enough when you're driving, especially driving hard. The fenders can be rolled by a good shop and you can trim the ends of the bolts that hold your well liners. but you won't really know what the suspensions compression is going to do unless you have a couple a fat guys sit on your fender while you turn the wheels back and forth.
So, that being said what's the offset of your new wheels ? How much have you dropped the car ?