TRWright

like the title asks, is anyone here running 235/40/18 on a 7.5" wheel?

I know that 225/40/18 is the 'approved' size up front, but I would like to know if anyone is running this and if they have had any issues.

TIA

LVDell

It won't fit and if if you could get it to fit you will still have the same contact patch as the 225 so no benefit to trying to get that rubber on there. You need at least an 8" wheel but even better is a 8.5" wheel for that 235.

springgeyser

It will mount up on a 7.5" rim but the sidewall will 'balloon'. Like Dell stated, the contact patch will be much smaller than if it mounted on a recommended size rim.

10 GT3

For the 993 Turbo and the 02'+ 996 Porsche used a 225/40-18 on an 8.0" wide wheel. On the GT2 and GT3 they used a 235/40-18 on a 8.5" wide wheel. I run this size on a set of 9.0" race wheels. Will it fit? Yes. Is it advisable? No. The primary issue isn't they extra that the tire baloons from the rim, it is the effect of the extra width. The result is much slower turn-in and some instability. The only way to compensate is to increase tire pressure, which reduces contact patch and overall grip. The bottom line is there is no performance advantage to over-tire sizing a wheel.

TRWright

Thanks guys, just wondering as a friend was going to hook me up with a brand new set for next to nothing.

LVDell

What wheels do you have?

TRWright

Dell, I have the 18" turbo look wheels. I thought they were replicas because I didnt see any numbers next to the valve stems, and IIRC all Porsche wheels have offset and width there? but the 18s are in my option codes, so I assume they are oem?

LVDell

Inside the wheel you should have a part number. Snagging a set of 8" turbo looks fronts off eBay, etc, ,would get you what you need to mount that tire.

Kevin H. in Atl..

The 18" OEM Turbo Looks do NOT have the width and offset stamped on the finished side of the wheel.
They are stamped on the backside of one of the spokes, along with the part #.