[Elijah Hua]

Hi everyone, Just wondering if I should install 255 35 r18 square for track day use? I heard that 255 40 r18 might rub. Will 35 rub as well? I'm also going to buy arc 8 18*9 et30 rims.

[JDAURIA]

I think you should be fine. I currently run 255/40 on my Front 513s and they are 18x9.0 (ET29). Guess it might depend on your suspension setup. I simply have ACS lower springs on stock struts. I have no rubbing whatsoever.

[MidtownMike]

Originally Posted by Elijah Hua

Hi everyone, Just wondering if I should install 255 35 r18 square for track day use? I heard that 255 40 r18 might rub. Will 35 rub as well? I'm also going to buy arc 8 18*9 et30 rims.

Your diameter and circumference would be 4% smaller than standard, but not sure if the front tires may be too wide and rub.

[visionaut]

I don’t think you’ll gain anything going to a 35 vs 40 aspect ratio. The 35 aspect ratio is same section width and even slightly wider tread width. And the diameter is 1” too short (F3x OE diameter is 26.0).

Using Michelin PS4S as example:
255/35-18 = Tread Width 8.8”, Section Width 10.2”, Height 25.0”
255/40-18 = Tread Width 8.7”, Section Width 10.2”, Height 26.0”

[danb1979]

245/40/18 0r 255/40/18s are what's needed - 245/40s look to be the better fit IMO

That's my personal preference - 255s in some tyres look a bit too big; others look very square and should fit ok

[im_an_alien]

I just purchased 255/40/18 for my fronts, I'll put up pics when they are on the car. I've had the same size squared on the car before. Lowered on pro kit.