Hilton

Pre-S4 have 16x7 all round. All of them have 225/50/16 all round. (other than some early auto phone dials with 15" wheels)

These all have 225/50/16 front, 245/45/16 rear:
87-91 S4: 16x7 16x8 (forged)
90-91 GT: 16x7.5 16x9 (cast)
CS/SE/89GT: 16x8 16x9 (forged)

mickster

That's why I'm confused...the car is an 89 S4...with optional platinum wheels from the factory...guess they are 225 all around.

Hilton

They should be S4 size rims - the platinum option is just a change to the anodised finish, underneath it they're the same 16x7 and 16x8.

Unless someone replaced them with a less-scratached set from an earlier car (platinum metallic wheels are way more common on the 928S).

MFranke

You can still put a 225/50 16 on the 8" rears if you want.

James Bailey

the difference between the 255 and a 245 is 10 mm as that is the unit of measurement. Or the difference in inches is .393701 to be exact.

mickster

I'll check the markings/part numbers when I get it up on the lift. The Porsche option code calls out 225/16 in the platinum description.

Hilton

No need.

You clearly have the 16x8 rears which should have 245/45/16 tyres on them

The shape of them is different - the flat part is inset, unlike your 16x7 fronts. The option code info is a throwback to the early cars (where they are 16x7 all round).

upstate bob

the reason for asking is that it would seem that the fronts would have a greater side load in a turn even with a 50-50 weight distribution. they are angled more than the rears. I'm discounting any accel/decel factor. -I don't consider a 928 a serious drag car so big rears would not enter here either. fwiw I consider toy (fake) muscle cars with teenie fronts and humongous rears an abortion.

mickster

Thanks-see it now! Derp!

Jfrahm

I would not recommend 225s on an 8" rim but as I said 245/50-16 fits great and is a common enough size. I bought a car which had 225s on 8" clubsports and the curb damage was quite dismaying.

kmascotto

Mr Bailey you are correct...that said, even within a manufactures brands there are width differences, see below. i made my original comparison between # 1 and 3... I should have made it between 2 and 3. (as 2 and 3 are comp 2's)

1)The BFGoodrich 245/50R16 g-Force Sport has a diameter of 25.7" and a width of 9.6", it is mounted on a 16" rim with 785 revolutions per mile.

2)The BFGoodrich 245/50R16 g-Force Sport COMP-2 has a diameter of 25.7" and a width of 10", it is mounted on a 16" rim with 810 revolutions per mile.

3)The BFGoodrich 255/50R16 g-Force Sport COMP-2 has a diameter of 26.1" and a width of 10.4", it is mounted on a 16" rim with 798 revolutions per mile.

Here is the link where I've pulled this info from...http://tire-size-conversion.com/tire-size-calculator/

David Klink

I have driven on these on a number of MBs, and liked them just fine. I actually won't be needing them for quite a while, but they were so hilariously cheap for such a "correct" tire set that I had to get them. From Tire Rack, $550.00 grand total at my door. They are on "close out" status, so if you think you may want a set you may want to act soon...