964 Wheel and Tire Selection

[iamtheari]

Information on acceptable wheel and tire choices for the 964 cars is spread around a few sources, including Mr. Verburg's compendium of 964 vs. 993 differences, Porsche TSBs, aftermarket catalogs, and so on. Recommendations are even more spread out. I for one am dizzy with all the options, suggestions, and so on. My hope is that this thread will at least answer my own needs and also live up to my good intentions of having one repository of the information rather than just adding one more thread to confuse people in my position in the future.

What wheels and tires are out there for the 964 cars? What are the pros and cons of each? For example, for wheels, which of them will severely limit your choice of tires?

To start the thread out, my 1990 Carrera 4 has the stock Design 90 wheels:
Front: 6x16ET52 with 205/55R16 tires
Rear: 8x16ET52 with 225/50R16 tires

The largest Porsche recommends appears to be:
Front: 7x17ET55 with 205/50R17 tires
Rear: 9x17ET55 with 255/40R17 tires

The largest that Bill Verbug mentions in his compendium thread, with some fender rolling required for this wider end of the scale to fit the car, is:
Front: 8x18 (offset maybe 50?) with 235/40R18 tires
Rear: 10x18 (offset maybe 47?) with 265/35R18 tires

TireRack.com suggests (and mostly carries, as they have no 16" wheels and only the Sport Edition Cup 4 17" wheels available as of this writing):
Front: 8x18ET50 with 225/40R18 tires
Rear: 9x18ET43 with 255x35 tires


Does anyone have anecdotal or other evidence of good wheel choices and good tire choices for summer, winter, all-season, and track driving, respectively? I might relegate my Design 90 wheels to track or winter use, or may retire them completely. But I don't want to spend a dime on wheels unless I know they will suit me well. I'm sure others are similarly situated. Thanks in advance for anyone who can contribute to the topic.

[iamtheari]

I should point out one piece of advice that has come up in my searches for information: Increasing front tire contact patch reduces understeer in the C4. So maybe putting the widest possible fronts and slightly narrower than the widest possible rears is the way to go?

[djantlive]

i would not change the width of the tires. you can get larger rim with lower profile tires if you want to get better feel of the road. you can easily get dent or crack wheels with low profile tires though so be sure to get forged wheels, not cast wheels. i would look into either OEM ones or iForged.