sjfehr

Dunlop Star Spec or Hankook RS-3 are my recommendations right now for an autocross street tire- both are extremely fast and as good or better than other more expensive tires; the big difference between the two being the temperature range. Star Specs like it cold- they'll give excellent grip on the first run (and right out of your driveway as a DD); RS-3 need to warm up for a run before they're fast. They're not as bad as Kumho XS or r-comps with warm-up time, but they're slick when they're cold and dangerous when it's near freezing. [Do not even consider Kumho XS if this is a DD and you have to drive in the rain or the cold!] Both the Star Spec and RS-3 are good in the rain, but Toyo R1R and Continental DW are the best rain tires for autocross right now. If you're running a lot in the rain and competitive enough to justify the cost, then you may want to consider Conti DWs for the wet and r-comps for the dry. If you're in a cold climate and they're DD/autocross, get the star specs. If you're in a really hot climate and track a lot, RS-3 is probably the better choice. Note: the sidewalls of the RS-3 are soft and though they give excellent peak lateral grip, the star spec is better in transitions. So, the type of autocross your local club(s) do might impact this as well- star specs love tight courses and slaloms while RS-3 like more open courses with long sweepers.

NT01 and R888 make for good track tires, but poor autocross tires- they need higher temps than you can get in autocross to make them sticky.

FWIW, I run Star Specs and have done 3 seasons on them in street tire class, doing extremely well in my region with them. I'm still running them for DD, but I finally dropped for a 2nd set of wheels with Kumho 710s for autocross.

Yomi

I see I never did a followup to this in this thread.

I went back and forth on race tires for a long time. I ended up not doing it for both cost and space reasons (no easy way to carry them). Too bad because basically everyone in our region runs race tires and there are no handicaps or street-tire-index classes. Hard when your competition is sporting 335 Hoosier A6's.

I bought some Victor Innsbruck stock-width wheels with Yokohama AD08 tires, sized 235/40-18 in front and 295/30-18 in the back. Interestingly the 235 fronts are just a little narrower than the 225 Pirellis that were on the car before, so there is plenty of room. I bet with a very small spacer there is enough room for the 255/35s in front, which would help for autocross. Next time

I also found my car has a maxed out camber of -0.3 / -0.6 in front, and caster is just a little below factory minimum. I was really hoping for -1.3ish and expecting at least -1.0. Depressing for shoulder wear.

Impressions on the street: they're stiffer than the Pirellis and more tire noise. Not obnoxious, but more.

Impressions at the autocross: holy sticky rubber, Batman! Based on percent of top PAX from 4 events on the Pirellis and 5 events on the AD08s, they're about 2s per 60s faster. Obviously comparing new tires to old ones. The Pirelli PZeros feel ok and are very forgiving -- they start sliding and keep gently sliding. The AD08's are much different in that they grip, grip, still grip, then slide much more suddenly. I could explain it better using some force vs. slip angle graphs ala Haney's tire book. They're no V710 or A6, but dang they're better than the old tires. 9th overall in PAX at first event on them (still factory stock 2004 C4S - only changes are wheels, tires, and alignment) and only car in top 10 on street tires. My last event was on a very slippery asphalt lot, and I missed top PAX by 0.056 seconds, and again only car in top 10 on street tires. Fun trading off the class lead with a C4S daily driver vs. a trailered, Hoosier A6 wearing, Corvette with Tire Rack stickers. I doubt I'll get that happening again on street tires, but it sure was fun.


Based on what I've heard from national events and what the ST people are running (and changing to with wet vs. dry), I think sjfehr is right on. I would have liked some RS-3's but the sizes for 18" C4S are definitely not optimal (would put tall 285/35-18s in back and 245/40-18s in front). We get lots of runs each day (6-12) so getting heat usually isn't a problem. The AD08s seemed like a good compromise given that I'm basically losing a huge amount vs. everyone else on R compounds. Optimizing the street tire would be important if I were in a ST class or using an 0.975 handicap, but I'm not.

utkinpol

>I also found my car has a maxed out camber of -0.3 / -0.6 in front, and caster is just a little below factory minimum. I was really hoping for -1.3ish and expecting at least -1.0.

it can`t be so. mechanic has to undo 3 bolts that keep upper mounts then use crowbar and move upper mounts all the way inward. that is how you get -1 deg of camber. it should be possible.

Yomi

We did undo the three bolts on each upper mount, and it certainly looks like they're as far over as they go. We tried pushing and pulling, but nothing dramatic like a crowbar. I would dearly love to get more front negative camber, but also want to stay in stock class. So no slotting, no GT3 top mounts, no camber plates, no GT3 LCAs (I can legally use the replacement LCA with an eccentric, but that just adjusts caster), no camber bolts that I'm aware of (local parts dept. indicated no factory ones, and it's still 2011 rules).

Earlydays

My experience also...I've been running AD08's for 2 years on my 964 C2 in Street Tire and they are outstanding with excellent turn-in and grip. I ran Hoosier and Kumho R tires for years and I feel the AD08's are equal in initial turn-in, though of course ultimate cornering grip is not at "R" levels.
Another interesting thing I found was that after comparing specs of the "hot" street tires in my sizes, the AD08's were significantly lighter.
225/50-16
------------
AD08 23lbs.
RE11 27lbs.
Star Spec 26lbs.
RS3 25lbs.

Auto-X-er

Gotta hope Hankooks eventually rolls out more sizes for the RS3. This time last year there werent that many out so maybe they arent done. They are very impressive tires and in the porsche sizes I would assume they would end up being way cheaper than other similar tires.

silvermoon

anyone tried 19 inch wheels?

kpl

I ran Falken 615K's on my 4S's stock wheels. You have to go up to 235 and 315, but they fit well. I thought they were slightly better than the Yok's all around (grip, wear, price, etc.). I didn't have any rubbing, but was running 7mm spacers on the front.