Well it depends on the width of the rim. I have 18x9' on the front, and I run 265/35/zr18's. On the rear I have 18x10's. I have 295/35/zr18's there. If it's an 18x8 rim I'd go with probably a 245 or 255 all the way around. The stock rims on my Cobra were 17x8. They came with 245/45/r17's, so245's would be like stock.
__________________ C&L 80mm mass air and True Flow pipe, Mac CAI, BBK 65mm tb, Steeda non-piggy back ud pulleys, MGW shifter, RAM HD clutch and aluminum flywheel, 3:73 gears, 2.5" Dynomax o/r x pipe, 3" MAC cat back system w/ 3 1/2" tips, Kenny Brown(front and rear strut tower brace, caster plates, subframe connectors,extreme matrix brace,jacking rails, torque brace, lowering springs), Bilstein shocks, 03-04 Cobra(side scoops, rear bumper cover, top), 6pt roll cage, white FR500's, FMS 2000 Cobra R air dam. | 
What size of tire fo my rims? 
