Have read most posts on tires but have a specific question of seasoned autoxers. Ulira high performance street tires as appossed to the hoosier type slicks. large or small gap in performance? I auto crossed mine 4-2 and enjoyed it immencly but seemed at great disadvantage in class because of tires. ran a 52 secound run 350zs on good tires were at 47 48 sec so sol did well. VERY forgiving of my over enthousiasm. Power on auto cross course not lacking at all power spun a couple of times. anyway would appriciate a response because there is a large differance in price.

The gap between R-Compound tires and high performance tires varies on several factors: wear rating and compound of high performance tires, length of course, type of car, driver, etc. Generally speaking and all other things equal, R-Compounds would produce a time 1.5 to 2 seconds quicker than high performance tires on a 60 second course.
Dan

And i would suggest running street tires - if you are a novice - for the first year or so. Practice your driving before making the jump to race tires - it'll make you that much faster when you do go to R-tires

I was going to go with R-Compounds but primarily due to funds I'm more seriously looking into high performance tires instead. However I do have a set of extra wheels so the tires I want to get are ones I don't intend to use for daily driving. I've been looking at the Falken Azenis RT-615's since several people here and people at races I've been to have suggested them along with GRM. Those tires are also Street Tire legal if you want to do something like Street Mod Street Tire (our cars are in SM2 I believe since we're 2 seaters).

If you're looking for a high quality every day tire you plan to use as your track tire too the Eagel F1 GS-D3's are supposedly very highly rated.

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You have mentioned these so many times (and I have them written down) that I'm going to get these. Thanks

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Deep, Ebony
O Sol O Mio

I have it on high recomendations from many sources that these are excelent tires for the base wheels/car.

Also talk to LatinVenom too, he has them as well and raves about them.

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I'm solidly in the Azeni RT-615 camp.

http://img.photobucket.com/albums/v4.../BG05AutoX.jpg

Here are the results from the Camaro/Firebird reunion Autocross in Bowling Green last September. I (Art Schroeder) and Steve Heino (in my car) were on the Azenis. Note: I hit a cone on my 3rd run.

A full range of other street tires were represented and I know that Elie (bottom of the list) was on the Eagle GS-D3's.

As far as street driveability goes, our trip to Bowling Green first took us west to Alberta, then south through Montana, Wyoming, including Yellowstone Park, snow at higher elevations and heavy road construction areas, all told, a 5,000 mile round trip.

You might also want to compare price.

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Sly '07 ZOK

Yeah, I've found the RT-615 online for $150 each compared to the F1 Eagle's $210. But that's because the RT-615 only comes in the 245/40 size and not the 245/45 stock size which is a much stronger load rating size. It also means your speedo will be off slightly due to the incorrect sizing. Which is why I'll get F1's for day use and RT-615 for my track wheels.

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why didnt you go with the 255/40/ 18 in the falkens they are closer in size?

I haven't bought tires yet myself. Still newb to tire sizes, what's the benefit of the 255/40 over the 245/40, I believe that's a wider tire correct?

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240/45 R18 tires have a rolling diameter of 25.72 inches and a contact patch of 9.65 inches.

Here's the math for the rolling diameter: ((2*240*(40*0.01))+(18*25.4))/25.4
And the contact patch: 240/25.4

Now when using 255/40 R18, they have a rolling diameter of 26.03 inches and a contact patch of 10.04 inches. Also, Solstice stock tires are 245/45 R18s with a rolling diameter of 26.68 inches and a contact patch of 9.65 inches.

Supposedly you can squeeze 275/45 R18s into the wheel well but I've yet to see anyone try it outside of Mallett and his V8 conversion. 275/45 R18 tires have a rolling diameter of 27.74 inches and a contact patch of 10.83 inches.

Anybody looking at fat tires may also consider lighter rims.

Goodyear Eagle RS-A:

235/55 R18 = 29 lbs
245/45 R18 = 28 lbs

Goodyear Eagle F1 GS-D3:

245/40 R18 = 26 lbs
245/45 R18 = 29 lbs
255/45 R18 = 31 lbs
275/40 R18 = 28 lbs

Bridgestone Potenza RE050:

245/45 R18 = 27 lbs
275/40 R18 = 28 lbs

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So high, so low, so many things to know.

VIN 8694 delivered on February 3rd, 2006. Two years later and I'm still enjoying it just as much as the day I took delivery.

DDM Stage II and Spec 2+ clutch/flywheel finally installed :)