ccaarmerciill

I had the "old" Dunlop Direzza Star Spec ZI's on my E36 M3, which was a great tire. Daily drove amazingly, did well enough in the wet, and kept me very competitive in STU class for autocross in a good squared set-up. I made the mistake of not reviewing the SCCA rules before jumping into replacing tires for my 996 (Tires PO had on were horrid). I jumped into getting the new Dunlop ZII's, and was really excited about trying the new tires out on the road and in autocross. Read the rule book, and apparently there isn't even a street tire class the 996 is allowed in (oops). So, to even think about competing in A-Stock, I guess it's time to go for a dedicated autocross tire/ wheel package. I think the Kumho V710 is my best bet, I'll take the slightly slower times for vastly increased longevity... it'll push me to perfect my runs even more so than on the Hankook A6's.

This really wouldn't be much of a problem if it wasn't for the new ZII characteristics. I found the ZI's to be very road friendly, road noise was bearable, stiff sidewall but not crazy, and lasted a decent amount considering how well they performed. These ZII's are a step above the ZI's, noticed instantly from even the little road driving I have done. The sidewall is much stiffer than the ZI's, and on the highway there is some very evident "howling" from the tires... they also seem harsher as well. I wouldn't be so upset about all of these qualities if I was going to use them for autocross as well as street (espescially knowing they are a faster tire than the predecessors). Now I have tires that I'm stuck using just on the street, that aren't very good street only tires. (I guess I could do a few autocross events for fun, but knowing I won't be able to compete will kill it for me a little)

If I could do it all over, I'd get a more "luxury" summer tire, and obviously get those V710's for autocross duty. Lesson learned, read the rule book before doing anything to the car.

sjfehr

It's odd you say that; I've been driving on ZIIs on the street for a couple days now and have heard no noise at all. I've got nothing but great things to say about them as street tires, actually. Thanks to schitzophrenic VA weather, I've gotten to drive warm, cold, wet and dry and grip in all conditions has been fantastic. No road noise, no slipping, and very comfortable. Night and day over the well-worn star specs I replaced, HUGE increase in performance. The rear tires felt a little soft during some hard cornering, but there's no evidence of any rollunder. I figure I'll have much more to say after this weekend's autocross.

I think you're going to be unhappy with V710s- they're 2nd tier compared to the A6 and ZII will probably be just as fast- or so close to it that you'd not notice except that it's going to take you 4 runs to get them up to temp. You'd be better off just running your ZIIs in AS, I think. Why aren't you running in RTR, does Hawaii region SCCA not do that? You should petition them

ccaarmerciill

I haven't actually done an autocross since last year, so unless it was added recently... I wouldn't know about it. RTR sounds good to me!

It's odd how you have zero sound. At certain highways speeds (50-70 mph) the tires make a very audible high frequency howling sound. Wonder what the difference could be, maybe the wheels I am running? Similar thing happen with my ZI's, I had a newer set that had maybe 1,000 miles on them on a set of wheels. Ended up selling/ trading the wheels with the tires still on to someone before I sold the car. He complained that the road noise was unbearable on his car... I never noticed it on mine (on the BMW) any clue?

Thanks for the heads up on the RTR class by the way.

sjfehr

I'm running slightly different sizes in my Boxster S than you are. Could just be something with harmonics in that size tire, or something unique to the way some roads are surfaced, I don't know; I've never had droning in any of my tires at any depth.

Easy fix: drown it out with engine noise and tire squeal, that way you won't notice!

Last year was the first year for RT* (RTR, RTA & RTF) as an official SCCA class. Turnout at nationals in RT* was fantastic, even as just a provisional class, and it's spurred a lot of local regions that had not previously done so to adopt either RT or their own version of it for this season.

ccaarmerciill

Just checked the results from recent solo events, and it doesn't seem like they are running RT classes yet. Still have the usual STU, STX etc classes. What's funny is there isn't anyone running in A-stock class, so either way there's a chance I'll be in a class on my own. There are a few people consistently competing in A-street prepared, so may have to play with them.

I'll petition for RTR though, I'm sure a few people will join in.

Earlydays

Just run in the PAX indexed Street Tire class......

sjfehr

Friend of mine had his new (to him) C6 Z06 corvette at a local autocross test & tune yesterday. It was shod in PSS, which he referred to as "complete garbage" and said he hated them on the street just as much as for autocross, complaining they had no grip and were downright awful and dangerous in the cold, breaking loose in 3rd gear going through intersections with just moderate acceleration, etc., and he couldn't wait to take them off and put on some "good" tires.

Guess a lot of is is just a matter of perspective?

knfeparty

yeah RTR should be an option. I got r-comps for the 996 and while they are cool, it is such a pain with the trailer and whatnot.