talon95

Hey guys, I've read most of the threads on the forum, but I'm still not sure which way to go. The deal is, I'm a long time SCCA Solo competitor. I've always run on R tires, but with the cost, I'd really like to run something cheaper at local/regional events.

So, I've tried running the street tires I have now (Firestone Wide Ovals), but they're pathetically slow. I'd say there is a good 3 seconds between them and a reasonably fresh set of A6's on a 50 second course.

Question is, would moving up to a better street tire, like the Kumho XS's make up for a significant amount of that 3 seconds? Like a second or more? Or should I just bit the bullet and buy an additional set of A6's??

I haven't owned any of the newest top street tires, so I don't have a good feel for how much might be gained over an older generation tire like the Wide Ovals.

Thanks,
Dave G.

rasrboy

What kind of car and mods do you have?

talon95

Oh yea, it's a C5Z that I run in Super Stock. So no mods other than alignment and Koni 3013's.

Dave G.

Solofast

I was at the Cen-Div solo seminar a couple of weeks ago and the guy from the tire rack was saying that they were getting really great grip from the latest generation of STS tires. They are supposed to be so good that they don't give up a lot to R rated tires. Look at what it the hot tire in STS and go there. They got almost a full season on a set of (I think it was) Dunlops and drove cross country to their events. Wasn't a total daily driver and the tread life isn't great, but it's in a different league than R rubber, it's really dual use stuff. In STS there's a min treadware limit, but in reality the tire manufacturer puts any number on it that he wants to. Those tires would probably overheat on a track day, but they are the hot setup for dual use autocross.

Also not sure if the hot tires in STS are available in Vette sizes, but it's worth taking to the national level STS guys to see what works.

avizandum

I've run Kuhmo XSs and Bridgestone RE 11s on my C6 Z51. They'll blow away the Firestones. The XSs hold better in super hard cornering, but they don't grip accelerating or braking as well as the Bridgestones. Plus they like a little heat where the 'stones grip cold as well as warm. I am currently running big, fat A6s on wide CCW rims - more fun and can drive the car like it's built...

Omaha02Z06

The XS's do well with heat and aren't so good cold so you may be better off with some Nitto NT05's. I have the Nitto's and love them. Since your in the MiDiv region you'll know who I'm talking about on this one. On Christy Carlson's STU STi which Pat Lipsinic co-drives they have found the XS's to work great for Pro Solo's since it's a fast pace event and they can keep the heat in the tires but for Solo events the Dunlop Star Specs work better with lower temps. No idea on how the NT05's or XS's compair to A6's on the same course time wise.

TMyers

Been running the XS for the last 2 years. Stock is not in the same class. I have been running stock class, no R-compound tires and I am within 4 seconds of the guys in full race setups, and consistintly beating the stock Z06's with my F55 C6. I have 48 runs plus around 4000 miles on them and still have tread left. On cold or raining days I just run my normal tire.

I am looking at running the RE11 this year because of the good things I hear and I can upsize. I also am looking at the R888 possibly.

talon95

Yea, I've been following the ST classes for a while. I'm just trying to get a feel for how much I might gain by replacing the Firestones. You've given me an idea though. I might shoot an email to the TR guys. I know both of the guys running in STR from my days of running a Miata in stock classes. Obviously this is a difficult question to answer though.

In response to all of the comments about some of the other top ST tires, the C5Z has been somewhat left out in the cold when you're running stock rims. The only companies making correct sizes are Kumho (XS), Nitto (NT-05), and Falken (615K).

Dave G.

rws.1

I did not think the XS was available in stock C5 Z06 sizes.....

talon95

They don't. I was looking at the 295/315 combo which is the same sizes I run in A6's. Might not be quite ideal, but better than getting stuck with a 275 on the rear like Dunlop and BStone offer.

Dave G.

TheNick

Dave here is the deal on ST tires - this is coming from experience with a high power (relatively speaking) STR S2000 on narrow tires and will be more applicable than the data from Chris and Woody (especially considering they haven't tested the Toyo or Hankook yet as far as I know)

Toyo R1R - best longitudinal grip and turn in out of the whole group. Slightly sloppy feeling sidewall but this can be tuned out with shocks. Works great on Lincoln concrete. Dual compound tire that goes away at the wear bars, we could get 50 runs out of them on the Honda after starting from full tread. Phenomenal in the rain and cold weather. Easy to overdrive because of the sidewalls and margin for error with slip angles.

Hankook RS3 - best lateral grip, really soft sidewall. Expect to run a full degree more camber than any of the other tires. Not great under power. We got about 150runs and 6000 street miles out of them last year, but they were really really dead at Nationals (our biggest mistake). Works well in the rain and cold (contrary to popular belief)

Dunlop Star Spec - crap. vague, horrible turn in, no grip anywhere compared to the R1R or RS3. Works well in the rain and cold.

Kumho XS - horrible longitudinal grip. Only works well on certain surfaces and requires a lot of heat. BAD rain tire

Falken 615k - probably the best compromise of all of the above. Haven't run them yet, the only person I know who has is Hollis.

Nitto - Doesn't compare to anything from the above. Probably most comparable to the Kumho though where it requires a lot of heat.




Find the right tire in the right size is the most difficult part. I'd probably run R888's or RA1's if I was looking for a streetable tire that lasts a long time. That being said, you should be getting 80-100 competitive runs out of a set of HooHoo's before they cord or you are doing something wrong. Dave O'Maley won the Toledo Pro a couple years ago on 110 run A6's against Braun and the like. Shock valving can have a lot to do with tire wear...but you also run on concrete fairly often compared to Dave.

talon95

I'd probably go with the 615k's except no-one seems to be running them, so it's unclear how they compare to some of the other top ST tires. Maybe I can bug Hollis at some point. I always loved the original 215's on my Miata years ago.

If the XS's are that bad longitudinal, then that's the wrong tire. That's my #1 complaint with the Firestones. Can't put power down to save your life.

As far as wear on the A6's, I used to get 80+ runs out of them when we ran on a lot of asphalt, but now I run mostly abrasive concrete, so that # is definitely going to be lower.

Part of the reason I was looking at street tires was so I could run in whatever street tire classes and maybe make the June event down at Mineral Wells.

Dave G.

Han Solo

Recently tried the Nitto 555 Extreme Performance Radials in hopes they would be decent for autocross and also safe for rain on the street. Gonna go back to race tires next event. Just not the same going 3 to 4 seconds slower.

Granted the tires I bought are not considered an autocross street tire but I need my race tire fix bad after two events.

NealB

TheNick has it right. Toyo R1R or Hankooks are the tires to have in STS. Heavier cars seem to like the Hankooks, and some have tried the Yokohama AD08 with limited success.

I'll be at the MW event. Decent grip asphalt surface, and only a 40 mile tow.

talon95

Unfortunately, neither the R1R or the RS3 is made in Z06 sizes. Well, thanks for all the responses guys. I think I'm sticking with just running the purple crack.

Edit: well unless I switch to the blimp tires...

Dave G.

Omaha02Z06

Too bad some of these other good street tires don't fit our stock wheel sizes.

Another person's brain you could pick on how the Kumho XS's perform is Mark Jorgensen's. He has ran them on his Viper in the past.

Gordy M

If you are running a stock C5, the Hankook 615's will work very well. 255/40/17 and 275/35/18 sizes will fit the stock wheels. I have a 4+ year old set of 615's I have run on occaision, and have had the fastest ST time in AS and SS, though I do have an occaisional problem with pylons this year. The rear tires don't like cold weather.

wanabgts

I have been running the xs's on my C4, and have been very impressed with the grip all around. Puts down power way better than the g-force sports i had before and they build heat quickly.

I have run almost every st tire there is, and if its dry and reasonably warm i choose this almost everytime. Especially because the outside tread blocks are massive so they wear MUCH better than alot of the other tires if you car doesn't have a alot of suspension.

That being said, pretty much any of the recent street tires will blow yours out of the water as far as speed. Alot of the time I settle on which one of them feels the best to me, since street tire times come from driving consistantly past the traction limit more often than not.

zack

justkickin

How did I miss this thread the other night in my searching.

I too am looking for a decent autox tire for a C5Z06. Currently have Firehawks on the car and was at an HPDE and they are brutal, especially in the wet. Accelerating was a simple no, and braking was entertaining to say the least. The second, set of wheels are still arriving in boxes and they will get a decent set of tires, just can't decide which ones.

Been leaning toward the XS as this is not my daily driver, but the RS3 is half the price. Is the RS3 that much better longitudinally that it can give up 30mm and still beat the XS longitudinally on a Z06?

I may try the RS3 or the skinnier Dunlop and see what happens.

As for the new 615K, for that money, I would rather get A6's, but the surfaces here would kill A6's in nothing flat.

Omaha02Z06, do you have contact info for Mark? I would like to hear his thoughts on the XS's. Please PM or email me if you don't mind. Talon95, if you contacted Mark, could you let me know what the outcome was? I don't want to bother him with the same questions if you already did.

Never thought getting good tires for this car would be so problematic.

Edit: Forgot to mention, a friend up here with a supercharged Mustang advises against the Nittos for autox. Street they are fine, just not enough grip for autox.

Tim

talon95

No, haven't talked to Mark. Figured I'd run in to him at Lincoln at the end of the month.

I think the only real option is the XS. I personally couldn't bring myself to put less than OEM size tires on the car. Just seems wrong.

Dave G.