Kika

Keep in mind, different makes and models of tires will be slightly different.

There can also be variations from car to car, recall that the 993 was also partially assembled by hand. The 993 was the beginning of Porsche's transition to Japanese auto manufacturing, hence the increased production numbers in the subsequent 996.

Vq-1

Understand, what are your thoughts about tire size/height when running stock suspension on a 1995 993?

Kika

I am running 225/40 and 285/30 Sumitomo HTR Z IIIs on 18s. RoW M030 springs and Bilstein HD shocks. If I were to go with a different tire, I would probably go 265 in the rear as that will probably be more neutral, although I like the way my car currently handles.

I am not sure what you mean by performance issues, some combinations will be more under steer or oversteer than others, but where you want to go depends on where you are now.

If you search, there is a really good oversteer/understeer listing that tells you all the ways to increase one or the other. I used to have it bookmarked, but all got deleted when we got a new Mac at home.

Vq-1

Thanks for the feedback, performance issue such as decrease 0-60 performance, increase fuel consumption, decrease top speed. Because I was thinking about going with 235/40r18 front and 275/40r18 rear or 225/40r18 front and 275/45r18 rear for a different look with the taller side wall profile.

Martin S.

The taller the sidewall, the better the ride. I was running 285/30/18 rears with the proper front tires....shook the fillings out of my teeth. Git rid of the tires and upped the side wall size (%age of tread width). For the track....I use the lowest profile tires I can mount up.

A nice street set up, track too for that matter is:
Front: 225/40/18
Rear: 265/35/18

The track junkies may stay "nay-say" on this...but also remember that these slightly smaller tires could very well be lighter, they for certainly be cheaper.

porschemikeandnancy

The tire pressure page from my 993 owners manual: My question is why would a small increase in tire size create such a large decrease in rear tire pressure? Even though the manual recommends 36 rear (44 with 16's) on my 17" wheels (optional factory 17" wheels), I've been running 44 psi for my 6 years of ownership.

What I can report is that both front and rears have worn evenly across the entire tread. One reads that if you have too much pressure, the center tire wear indicator will be reached before the edges of the tire. That has not been my experience. Also, I don't notice any difference in handling with 44 rear vs. 36 rear.

Again, why the OEM recommendation of only 36 with the 17" vs. 44 with the
16" wheels?

Kika

Higher tire pressure will help fuel consumption due to lower rolling resistance, so I would think a narrower tire would have the same effect. I wouldn't set my pressure based on it however, I set my tire pressures for handling concerns.

0-60 and top speed are probably more affected by tire diameter, but the difference is so small %wise, that again, I doubt it would be a noticeable difference.

Martin has it spot on with regard to ride comfort, although I have 285/30 s on the rear of my car, and I do not find it harsh at all, but that is just my opinion. The 993 is far more comfortable than my 911 SC was.

Tires have a great affect on handling and comfort, I would focus on your needs in those categories first. Realistically how critical is 0-60 or top end speed on the street? If you are seriously tracking the car, then you shouldn't be looking at street tires anyways.

Mike J

A lot of this is really subjective - I am running 30 series on my 19's on the turbo - great ride, not jarring at all, use them all over town and on longer highway rides - but then again I am also running KW Variant 3's as well, which have a really nice ride and are good at dampening ride impacts.

The shock/damping system can have a great impact on the ride quality as well, so the tires/size/shocks/springs/sways all have to be considered since they all impact feel of the ride. When I went from the stock shocks to the new shocks with exactly the same tires/wheels, the smoothness of the ride improved quite a bit. The stock shocks of course were totally shot.

Cheers,

Mike

irule

just found this thread. my tires are not in that pdf file.

i thought Michelin Pilot Sport PS2 was recommended for 993 models. Am i wrong?

(i have PS2 N3 in my 95Carrera)

irule

And i've read that pressure in back tires must be 44 (and not 36). Anyone confirms this?

Martin S.

The pressures are posted on the driver's door and spelled out in detail in your owners manual. 17" and 18" TPs are different.

mpruden

^^^ agreed. They're also posted in the PDF discussed in this very thread.

geolab

hello, every TSB has a date of publication, on the top right.
When this particular TSB was issued, the PS2 was only spermatozoa

last year's TSB has the PS2 recommended here:

irule

mine has 17 inch wheels. so 36 psi all around.

but i read somewhere that 44 psi is better in 17inch wheel too.

irule

thank you. where can i find that document? where is it released?