I notice the stock rear tire size (285/18/30) is only available from a few tire companies.

Has anyone come up with a good street/highway 18" combo that uses a narrower rear? Or would Dr. Porsche want me to stick to the stock sizes?

I don't plan on tracking or AutoXing my future 996 - so would a 285 rear tire be overkill?

 

The 3.4L 996's came with 7.5" front wheels, and 10" rears with 265's.
The 3.6L 996 has 8" fronts, and 10" rears with 285's.
Going to a 265 on the rear of a 3.6 would decrease rear grip somewhat and make the car more neutral and with less understeer, but with less overall rear grip.

Have you decided which model (3.4 vs 3.6) you're going to buy?

 

Stick with the stock size for the 996 you are buying (Mk I vs Mk II). The tires of a car are probably the most important part of the suspension and can define how a car behaves.

There are few choices in this size, but they are good choices so it's OK.

Don't go to a smaller tire just to save a few bucks. Believe me, if you can't afford the tires for this car you can't afford to own the car considering the prices for all other parts and maintainance.

 

I hear ya. I just didn't want to buy a car, spend $900 on tires, only to find out I should have gone with a different choice for basic street use, etc.

Not sure which car I will wind up getting. I'd like an '02, but also like the '01s that are nicely loaded. So I guess it will come down to which car has what I want.

 

I asked this question about Michelin PS2's because that is what I have and they appear to be no longer available in this size. I really don't want to mix tire models and I know I will need to replace the rears long before the fronts. The suggestion here is that the 295/30 18 size, which is still made, will work in place of the 285's without difficulty except that, understandably, you might have just a bit more understeer.

 

Note that the stock rears on the 3.4 were actually 255s. (205 up front).

I was able to pick up a pair of rear tires for $420 or so. SO2s.

 

Those are tire sizes for the 17" wheels
The previously mentioned sizes are for 18's.

 

Simple question:

On a 10" wheel you run a 285/30 tire with 38 psi. On the same wheel you switch to run a 295 tire with 38 psi. Which tire will have more contact patch? The answer is neither. The contact patches will be the same size, just different shapes. The only way you can gain grip/contact patch with a wider tire is to reduce tire pressure. This means increasing the problems with the extra sidewall flex you just added from the extra width of the tire. This isn't a problem if you are just concerned with going in a straight line, but a big concern for the corners. The only way to fix this is to use a wider wheel which eliminates the sidewall flex. If you ever wonder why Porsche uses a 285 on a 10" and a 295 (less than a 1/2" wider tire) on an 11" wheel? This is the reason why.

To follow up from Kevin:

The base wheel and tire package on a 996 Carrera was 17x7.0" front wheels with 205/50 tires and 17x9.0" rear wheels with 255/40 tires. Since most of the cars we see have the optional 18" wheels, we tend not to think about the 17's.