Bill Verburg

Check w/ the tire manufacturers they all publish a recommended wheel width for each tire, Tire rack includes that info in thier tire specs.

Most 225/40x18 tires have a recd wheel of 7.5 - 9"

A couple of other comments
for max perfomance from a given tire, use a wheel from the wide end off rec.
for max comfort use a tire at the narrow end.

While a 285/30 can certainly fit in the wheel wheel(w/ the right wheels and suspension settings) the desireability of doing so is questionable, putting stickier tires in the back dials in additional understeer(in addition to the width recs from a above). Of couse it can be dialed out w/ a fully adjustable suspension. But for most n/a 964/993 225/265 or 235/265 or 235/275 is a better choice. 245/285 would be good too.

The characteristic where the 285s shine w/ a stock US g50/20 is their lower height which helps acceleration response at lower speeds.

DJF1

Bear in mind that the Toyo 275/35/18 is standing 25.6 inches tall, which is taller than a 285/30 or a 265/35. In effect it makes the gear ratio's longer, not a great thing IMO with our stock 993 gearbox. I know I'm neat picking, but I thought I would point it out. In that tire there is not much choice for our cars, but it does match perfectly with their 245/40/18 which is good.

Bill Verburg

I agree 100%, the last thing you need w/ a stock trans is taller rear tires

V

Jeff, just a little remark (which I assume you already know of). If you have a 993 C2 its not really a problem but if you have a 993 C4 you should really pay attention to the circumferance of the front vs. the rear tires when you consider changing tyre widths... Otherwise this can cause serious damage to your transmission.. Anyways you probably know this already but still.. Just my 0.02$

Bill Verburg

All 964/993 need to keep the tire radii f/r nearly the same because of ABS, As I recall the figure is something like a delta of 5% unless the wheel speed sensor rings are changed

Acropora

For folks w/ a widebody 275fr and 335r 18" ra-1's will fit w/ rolled fenders.

slvr993

Well after searching the specs it looks like I'm limited to a 225 front. So that means 275 rear with RA-1s. No budget for new rims right now.

tj90

Bill - your right - 5% difference in front and rear and youll trigger ABS warning and disable the ABS system on any 993....

DJF1

Why this tire only? Are you looking for a DE tire?
The Sport cup comes in Porsche sizes and the new Nitto NT01 which is becoming the new rage comes with a 235 front which will match better the 275 rear.

slvr993

All the specs I've checked call for an 8 inch rim for a 235 tire. My fronts are 7.5. Am I spliting hairs. Any issue with a 235 on 7.5 rims??

I haven't checked out the nitto's yet.

Jeff

Paulsha911

Don't mean the complicate things. I found out quite by accident that even if the same specs, two different model / brand tires can have very different tread width. When I'm experimenting with a new brand, I always compare with a known setup that I know, against the tread width info which can be found to TireRack or the manufacturer's web site.

Harold_C

Is that for both fenders (F & R)?

If you didn't want to roll them, what are the widest tires that would work?

A little background: I am considering selling me '03 M3 that is setup for the track. I run 275 RA-1s all around. I'm considering getting a '96 C4S and would like to run it one the track with either RA-1s or NT-01s. Considering the limited tire sizes available, what do you think?

TIA!

-Harold

Chris M.

Really? I know I've heard of people running 225s on 7X17 inch fronts. HERE is the thread I was thinking of.

allill

do you have photos running these wide tires? it must look amazing!


chris m., your 964 looks great with the orange body colored wheels. any more photos of it?

Acropora

If you dig thru my old posts you'll find pictures. Even more important than looks, the wide tires really improve traction thru the corners.

Wondering what a secondary bypass is. Have been toying with the idea of installing electric cut outs to bypass my mufflers.