Tire size

[Dharn55]

My 00' C4 Cab came with the 18" wheels (8" and 10") and the stock tire sizes (225/40/18 and 265/35/18). I am upgrading to new 18" with 8.5" and 10" widths. I found that the new 997's have changes the tire size on 18" wheels to 235/40/18 and 265/40/18. What do you think abunt running theses on a 996?

I thought it might close some of the opening around the wheels and body without new springs/lowering. Does anybody see or know of a problem with this set up?

[Jorge332655]

I have 19inch Iforged rims on mine. The rear tire is 285 30 19 and it fits ok. The car is lowered. Dont know if thats what you were asking..

[KevinC]

My 00' C4 Cab came with the 18" wheels (8" and 10") and the stock tire sizes (225/40/18 and 265/35/18). I am upgrading to new 18" with 8.5" and 10" widths. I found that the new 997's have changes the tire size on 18" wheels to 235/40/18 and 265/40/18. What do you think abunt running theses on a 996?

I thought it might close some of the opening around the wheels and body without new springs/lowering. Does anybody see or know of a problem with this set up?

The problem is that your car was designed for equal size front and rear tires. The 997 was designed for the new sizes which are about 1" larger in diameter in the rear. The difference in tire diameters could cause problems for the 4WD system, ABS and PSM.

[Dharn55]

My 00' C4 Cab came with the 18" wheels (8" and 10") and the stock tire sizes (225/40/18 and 265/35/18). I am upgrading to new 18" with 8.5" and 10" widths. I found that the new 997's have changes the tire size on 18" wheels to 235/40/18 and 265/40/18. What do you think abunt running theses on a 996?

I thought it might close some of the opening around the wheels and body without new springs/lowering. Does anybody see or know of a problem with this set up?

The problem is that your car was designed for equal size front and rear tires. The 997 was designed for the new sizes which are about 1" larger in diameter in the rear. The difference in tire diameters could cause problems for the 4WD system, ABS and PSM.

You see alot of owners running non-standard size tires. I have looked at the relative sidewall heights as follows:

225/40=90

265/35=92.75

235/40=94

265/40=106

Many recommend 275/30 and 285/30 on the rear

225/40=90

275/30=82.5

235/40=94

275/30=82.5

225/40=90

285/30=85.5

235/40=94

285/30=85.5

With PSM and 4wd the concern is relative size. You can see that There is a wide variation of the delta in the sizes you see in postings here and on Rennlist. I believe these are all milimeters. The stock is only about 3mm, but you can see there are alot of owners running larger deltas.

Anybody out there running 275 or 285's on the rear and the standard 225 or even a 235 on the front? have you had problems?

[Dharn55]

My 00' C4 Cab came with the 18" wheels (8" and 10") and the stock tire sizes (225/40/18 and 265/35/18). I am upgrading to new 18" with 8.5" and 10" widths. I found that the new 997's have changes the tire size on 18" wheels to 235/40/18 and 265/40/18. What do you think abunt running theses on a 996?

I thought it might close some of the opening around the wheels and body without new springs/lowering. Does anybody see or know of a problem with this set up?

The problem is that your car was designed for equal size front and rear tires. The 997 was designed for the new sizes which are about 1" larger in diameter in the rear. The difference in tire diameters could cause problems for the 4WD system, ABS and PSM.

You see alot of owners running non-standard size tires. I have looked at the relative sidewall heights as follows:

225/40=90

265/35=92.75

235/40=94

265/40=106

Many recommend 275/30 and 285/30 on the rear

225/40=90

275/30=82.5

235/40=94

275/30=82.5

225/40=90

285/30=85.5

235/40=94

285/30=85.5

With PSM and 4wd the concern is relative size. You can see that There is a wide variation of the delta in the sizes you see in postings here and on Rennlist. I believe these are all milimeters. The stock is only about 3mm, but you can see there are alot of owners running larger deltas.

Anybody out there running 275 or 285's on the rear and the standard 225 or even a 235 on the front? have you had problems?

Actually on the stock set up 225/40/18 and 265/35/18 (with PS2's) the front are 829 revs/mi. and the rears are 822 revs/mi. so the rears are slightly larger diameter. However, with the 997 tires sizes, 235/40/18 and 265/40/18 this goes to 819 front and 790 rear. With a C$ the differential may be important.