earossi

I would like to mount some 17 inch wheels in place of the 18's on my 98 993 wide body car. I'm after improved ride comfort in my old age on these terrible Chicago roads. I noted that the 95 993 narrow bodies had 17's but much more narrow than my 18's. Specifically, I am currently running 225 and 285 widths (F to B) on the 18 inch rims. The 95 993 narrow body cars ran 205 and 255 widths on 17 inch rims.

So, I am wondering how much I will give up in handling running the smaller and more narrow tires than the stock 18 inch wheel and tire combos? Has anyone done this before?

race911

Well, you're not going to run a 205/255 combo, no matter how a base 2S was equipped. Handling in a street scenario is a non-issue.

Ultimately, a half inch of extra sidewall isn't going to make much of a difference. I'd just go for more of a comfort tire. I'll leave it to others to suggest what might work best.

95_993

Ken has a very good point. Tire selection can have as much to do with ride comfort at wheel diameter. A softer sidewall tire like the Conti or Dunlop may get you what you are looking for. Going to a 17 inch Dia and then ending up with a very stiff sidewall not make a difference. Now go to 17 in with a softer sidewall tire and you'll notice a difference and you'll likely notice a little mushiness.

What suspension are you running?

Martin S.

as Ken mentions, the stock sizes in 17" are 205/255. I have run this combo with street tires...much improved over the 245/285 in 18". You just wonk feel the bumps and pot holes so dramatically. A sporty 17" size, and still a higher profile than what you have, is 225/275 combo. I have run this on the track and a little on the street, this is a great combo.

Another advantage of the 17: over the 18", the tires are lighter AND they are cheaper too.

Self promotion: I am putting up some beautiful 996 7" front and 9" rear 17" wheels shortly. Check out my ad...and would possibly be interested in your 18" wheels. Potentially a win/win for both parties.

P-daddy

Ernie- like others have said, tire selection is key here. However if you still prefer to go 17s, my 2S came stock with Cup 2s with tire sizes you'd mentioned, and drove fine. In my experience, Dunlop Direzza IIs are very stiff. The Sumis have softer sidewall.

earossi

I've got a PSS9 suspension on the car, which I really like.

earossi

I replaced my 18's with a set of 17" Cup wheels fitted with 205/255 Conti Extreme Contac DW summer tires. I've had DWS's on my sedans for years and really like the ride quality except for the turn-in which is a little mushy.

The current 17" 205/255's give me the comfort I wanted, but they are not even close in grip to the Michelins I have on the 18" wheels. I fully realize the Michelin is a better performance tire. But, I like the softness of the Conti's.

So, how much better would a set be of 17" 225/275 Conti Extreme Contac DW's than the narrower tires currently fitted? Is it worth the effort to get a fatter set of the same tire? And, would there be much sacrifice in ride comfort going to the wider tires?

CaptainGSR

I swap between 17" Cup 2s (205/255) and 18" BBS Lms (225/285) all the time on my NB. I even have some 16" with snow tires (205/225) that I use mostly to store the car.
I have Pss10s.
I have tried Pirellis, Continentals (DW) and now PS2s on the 17s, and Bridgestones RE050 and Yokohamas AD08r on the 18s.

I can tell you that the 17s are my favorite wheels by far. The car does not handle as well as with the 18s (corners like it is on rails), but it is an absolute blast to drive: comfortable, quieter, significantly better acceleration... The limits of the car are much lower, and I find myself having much more fun with it, especially while taking corners.

The 16s with snow tires are a complete riot in the rain, but I would not recommend them... :-)

To each his own...

David993S

I would second the suggestion of trying Sumi's on your 18's. For street driving they are fine (not to mention inexpensive and long wearing) and you'll notice an improvement in ride quality over more of a performance tire with a stiffer sidewall.

Cheers.

95_993

I run the Conti DW on my Merc C300 and they are on the cushy side.

CaptainGSR

Changing tires on the 18s won't make enough difference in ride quality. You might as well keep your tires (if they are still good) and simply run them at lower pressures.

On California freeways, I could not run 36/44psi on my 18s (225/285) without needing to see a chiropractor after each drive. That's why I ran 34/38psi or even 32/36psi sometimes. Just watch out for nasty potholes. The rims are less protected in case of impact (I've never bent one.)
In the Alps, on smooth roads, 36/44psi is a blast. The car is a go kart!

I'd suggest you try and drive a 993 with 17s (36/36psi) before spending any money on anything. I run my 17s at 36/38psi in the Alps.

BTW: +1 on the Continentals (DW) in the USA... not as good as the Ps2s IMO, but very close in grip/comfort/weight, and so much cheaper!
In Europe, I would buy Ps2s (can't get the Continentals DW here anyways.) Sumis are probably awesome, but too heavy for me...

I hope it helps...

JDB1

Your car looks great with 18s. I suggest you simply get a seat cushion.

pirahna

I had Cup II's with PS2's and switched to 18" BBS's and Sumi III's. I much preferred the 17" + PS2 combo, more comfortable and seemed to be more confidence inspiring. I hated the flat spotting with the Sumi's. I am currently running Pilot Super Sports on my 964 and really like those but I don't know if those come in your prefered 17" size.

Bill Verburg

You get a comfier ride by using the narrowest wheels and the tallest side walls that you can fit, of course at the expense of performance.

Also remember that as tire height goes up acceleration ability goes down.

Drisump

Everyones expectations are different but I find my set up offers a reasonable ride and a good handling package. 18" twists, Sumis, stock tire size and running 40 psi in the rears (not the 44 listed in the owners manual) and PSS9's set to euro height ( and 2/3 hardness). I have driven this car on many >1000 mile trips and I never have felt beaten up with the ride. Good luck with your choices.