tacomaworld

I have a 1991 C4 with stock suspension - aside from a Rennline strut brace - that I intend to add coil-overs to down the road.

I confiscated a set of 17" wheels off my 993 that sold last fall. I believe they're referred to as "Cup 2" wheels.

I took them over to a friend's shop last night so I could remove the old, dry rotted tires (using his slick new Snap On tire machine, with all kinds of hydraulic arms that made it a minutes-long process even for a person that had never used it - definitely an addition to the dream garage). I was somewhat surprised to see that the stock front tire size from a 993 is 205/50/17, while people that track their cars seem to mount 225/45s. This, even though the "official Porsche" PDFs show 205/50/17 as the recommended size for both 964 and 993.

I'm curious if this is true (the 225/45 part), or if I am just pulling this information from a few searched threads... I like the steering assist that I get and feel that the car has no lack of traction in the C4 guise. I certainly don't want to run up against rubbing in the front end, especially if I end up dropping it a bit.

Finally... thoughts on Michelin Pilot Sport PS2s ??

boxsey911

We fit 225/45 for the track to give us more grip and reduce understeer. With many R compound track tyres (e.g. Toyo R888), you can't get them in 205/50 size which is another reason for using the 225/45.

Bill Verburg

There's stock fitments then there are oe optional fitments then there are aftermarket fitments
964 n/b oe fitments were
7 & 8 x16 w/ 205/55 & 225/50 tires
7.5 & 9 x17 w/ 205/50 & 255/45 tires
8 & 9.5 x17 w/ 205/50 & 255/45 tires

993n/b oe wheel fitments were
7 & 9 x16 w/ 205/55 & 245/45 tires
7 & 9 x17 w/ 205/50 & 255/45 tires
7 & 9 x17 w/ 205/50 & 255/40 tires
8 & 10 x18 w/ 225/45 & 265/35 tires

Much wider wheels and tires have been fitted aftermarket w/ custom o/s

C24FUN

On the front I use Yokohama 225/45 R17 A048 R-Comps for the track, mounted on a set of Mille Miglia Cup 2 reproduction wheels (rears are 255/40 R17). The difference in my setup is the Mille Miglia rims are 1/2" wider than stock on the front so they accommodate the 225s better.

Also with the 225s on the front I was getting some rubbing on the inside of the tub where the rear of the front tire made contact. I solved this by installing the thicker steering rack shims.

For street use I have a set of factory Porsche Cup 2 rims and use Yokohama S-Drive 215/45 R17 fronts and 255/40 R17 rears.

Hope that helps!

Jim G.

jellonailer

I run fikse wheels with Ntto Nt01's on the track in 225/255. Also have a set if Cup 1's with the same tires. (See avatar pic)

Try Hankook RS3's they are very good, and cheap too.

s4magman

You'd be happy with 225 in front but unhappy with 205.

964George

I'm very happy with 205's up front
I found that the 225's tramlined and made the steering very heavy
Switched to 205's and cup 2's and the car feels a lot my pointy, precise and nimble
Try both before you make a decision...

Goughary

For normal street driving, you have to be driving pretty fast and hard to have a really big difference in feel between 205, 215, and 225 up front unless you are using a very hard compound tire.

I am going to change from 205 to 225 only because I am due for tires and I like the look. But, with 205's the car handles great as it is. I never drive anywhere close to the car's limits on the street...so the tire width doesn't make much difference. Track is a whole other world of a balancing act. And I'd likely start with 225's and work the setup around the most rubber on the road.

boxsey911

For those considering using a 215/45 it's worth considering that you're making quite a large change to the rolling radius. A 205/50 has a tyre wall height of 102.5 mm. The 255/40 rears have a height of 102 mm. Changing to a 225/45 at the front is not much different as the height is 101.25 mm. But a 215/45 at the front gives a height of 96.75 mm.

964George

As boxsey states ^^^^^^^ you need to pay attention to rolling radius and especially as you have a C4 as I believe it can affect the PDAS...

Goughary

That's a good point.

ccamut

C24fun

Where are you buying the yoko's ao48 in the 255 size?

Thanks

louanneyis

I like the look. But, with 205's the car handles great as it is.

Railmaster.

Bump, i know!

I have noticeable problems with tramlining on poor roads with my 225 PS2 front tires, street use only, will 205s cure a little of that (993 Carrera 17 7 cup2 wheels in front).

PAOLOP

standard fitments 964 C2 or C4 are
front 7J 17 ET 55 205/50/17
rear 8J 17 ET 52 or 9J 17 ET 55 both with 255/40/17

964 RS
cup 1 magnesium
front 7.5J 17 ET 55 205/50/17
rear 9J 17 ET 55 255/40/17