coreseller

Yes I have already run a search. I've been to the Tire Rack site and wanted to hear from those who AutoCross their 993's. I would be mounting the tires on 18" stock size front and rear turbo twists. Thanks in advance........Mark.

lopro

Im most interested in this thread aswell.

Martin S.

18"??? Go to 17" for the track/autocross and save yourself a lot of $$$, or Loonies for those in the Far North. Let's be real here, there are street tires, and there are track tires….a manly man needs two (2) sets of wheels, at least two (2) sets.

A lot of it is all about how hard/soft the tires is. It's the DOT UTQG rating system..tires are graded by the manufacturers (Apparently DOT trusts them) from 40 to about 400. Generally a rated less than 140, is not recommended for the street even though it has a DOT approved rating. And don't think that a 140 tire will last long…pretty soft.

Your will note on the sidewall of these tires, at least the ones I have seen rated from 100 down to 40…the Mfg. makes note in raised letters, Recommended for for competition use only. This is a sort of liability release for them….and….Why not the street? Tread: Generally these tires have minimal tread depth, 6/32, that soon goes away. Some guys shave the 6/32 tire to 4/32 for optimal performance out of the box. Lacking any sort of significant tread, they would be hell to drive in the rain. Remember, the lower UTQG the number, the softer the tire. They will pick up all sorts of debris. A stock street tire will have 8/32 of tread, maybe even 10/32. Tires with this much tread depth may over-heat under autocross/track conditions, and possibly fail.

Best bargain tire that you can drive to the track, and wears like steel, is the Nitto NT-01 tire. About $1,000 a set for 993 cars. There are Toyo 888, most have stayed away from these.

The bestest (Not really a word but I like it) and cheapest approach, run 17" wheels, and run recommended Porsche sizes, 205 on the fronts, 255 on the rear. You can get away with 225, some times even 245 on the front…and 275 on the rear. A 245 should really be mounted up on a 8" wheel. There are Boxster 8 1/2" wheels that work great..be certain that the off set is about 55mm front and rear.

I bought a set of Cup 4 Chinese wheels from Tire Rack. Cheap, straight and true, and the fronts are 7 1/2" wide, allowing me to sneak a 245 tire up there.

18" wheels….for the track, you pay a premium for the tire, and they are heavier, more unsprung weight, not a good thing. And if you have 18" wheels/tires and think that by going to 17" they are 1" shorter for a lower gear ratio…this is not the case. Tire height is about the same.

Martin S.

3,628 posts, please, you already know all this stuff. You could write a book!

nile13

Mark, are you looking for a street tire? If so, you might already know that the minimum street tire rating for 2015 is 200. Are you in BS or Street Touring of some sort?

As far as tires themselves, there are 4 contenders for autocross. Dunlop ZII, Hankook RS-3, BFG Rivals and Toyo R1R. The first three all have their idiosyncrasies. ZII seems the most all-around tire. Rivals work well, but, apparently, don't like limited slip diffs, they tend to like sliding a bit. 'Kooks absolutely, positively need heat to work well. Out in Midwest you'll get enough heat in the summer but not in the spring or fall unless you have a co-driver. Finally, my favorite tire, Toyo R1R, unfortunately will not work at all as it is a 140 treadware tire as currently mark. Toyo is
working on 200 treadware R1R" and there's a lot of discussion as to when and where it'll be out, but it wouldn't help you if you need it now.

I personally ended up with Dunlop ZI as ZII was not available 2 years ago. The tire does well for occasional autocross and street. I did like the previous set of R1Rs better.

Regarding what Martin said above - if you run 17", the right combo would be 225/255 for autocross. This will, of course, depend on the suspension swaybars and alignment, but the rule of thumb seems to be that 225 will take cars of some of the inherent understeer.

PS. The above was about street tires. Those 4. There's simply nothing else of any consequence for autocross street classes. Oh, if you'd like, have a look at the nationals going on this coming week in Lincoln, NE. They show which tires people use in stock and Street Touring classes. I think that's all you'll need to know - unlike Tire Rack this is real world info without much politicking involved.

lopro

This is my first time sweetie I swear, That's my story and im sticking to it

Martin S.

I was giving your the overview, he drilled down to the specifics.

nile13

I also want to add that there's some significant difference in tire preferences between the autocross and track use. My experience is with autocross only, Martin can fill the blanks on track tires much better.

What I would suggest first and foremost is to decide what class you are looking to run at autocross and proceed from there. Plus, I'd think, you'd want to decide which is more important, whether you'll be driving to events on these tires or swapping them at events and a few other important nuances.

Vandit

BF Goodrich g-Force Rival

DJN

Tirerack: Dunlop Direzza ZII up sized sizes 235/40/18 and 285/30/18 $1030 per set.

Grip like glue, wear like iron! My purpose is full-on track use.

Enjoy!

uscarrera

If you are looking for track only tires I have been running Hankook on the race 993 for 4 years now very grippy and wear like iron, don't be scared off by the cheap price. Only downside is availability.
Rich

e9stibi

Here is another way to look at it: If you do not have any experience with performance driving, stay with a normal street tire to learn it. If you can comfortably operate them at the tire limit (not your limit), think about a more sticky tire.

cgfen

dual purpose AX and street = yoko AD08R
hard core AX = Nitto NT01
slicks = hoosier A6

go wider in front and narrower in rear if you want a car you can point and catch easilly.

coreseller

Some Great Responses so far guys, I really appreciate the input. I do have some experience with auto-crossing, but not in a 993. I've been running a Miata and have run the Direzza Star Spec's and currently have a set of Direzza 2's on it, also have a set of Hoosier A6's mounted on PanaSport wheels.

Since one of my sons will likely take over the Miata at the local SCCA events I was toying with the idea of running the 993 too instead of running the Miata as a two driver car. The reason for 18" wheels is that I already have the extra set of OEM Turbo Twists here. I guess I gotta decide if the 993 gets to have some fun too.....

nile13

Absolutely excellent, albeit a bit more expensive, tire. But... 180 UTQG rating means it isn't legal as a street tire next year.