Tires autocrossing a GT500
6/11/08 | 06:44 PM
#1
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From: Arizona
Tires autocrossing a GT500
I have been autocrossing for like 38 years and just bought a 2007 GT500. I know lots of people run the various forms of the GT in FS. I haven't seen anyone else run a GT500 in AS. I know it isn't competitive but it was fun. 
Of course that was on a faster than normal course.
With that lead in, does anyone have suggestions on the size make of tires to use. The OEM Goodyears were consistant if a little slippy. When I got the car the 285/40 tires were on the front and the 255/45 on the rear.
I guess that would a good setup for drifting. 
Michael
Of course that was on a faster than normal course. With that lead in, does anyone have suggestions on the size make of tires to use. The OEM Goodyears were consistant if a little slippy. When I got the car the 285/40 tires were on the front and the 255/45 on the rear.
I guess that would a good setup for drifting. Michael
6/13/08 | 12:57 PM
#2
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From: Arizona
OK, anyone know what is the largest size tire that will fit on either end? None of the 'R' tires come in the regular size but some come in 315/30-18, 315/35-18, 335/30-18, 335/35-18 or 345/30-18.
6/13/08 | 01:54 PM
#3
Hoosier A6 and R6, and BFG R1s will come in more "reasonable" widths in the 18" category.
17" tires are also plentiful, and generally less expensive.
The key concern I would have with wider tires is rubbing the front struts. The stock GT500 wheels have a 47mm offset and run the 255mm front tires, I've seen various people on here and magazines get away with 275s and even 285s on the front if you get some wheels w/ 35-40mm offsets.
Running a set of replica SN95 Cobra R wheels here...they stick out a little bit even with 255s on them, going to stick out a little more when I put the 275s in my garage on, but they are for the track only so who cares.
Where in Arizona are you?
If you're in the Phoenix Valley, check out www.clubracingaz.com for NASA road racing!
17" tires are also plentiful, and generally less expensive.
The key concern I would have with wider tires is rubbing the front struts. The stock GT500 wheels have a 47mm offset and run the 255mm front tires, I've seen various people on here and magazines get away with 275s and even 285s on the front if you get some wheels w/ 35-40mm offsets.
Running a set of replica SN95 Cobra R wheels here...they stick out a little bit even with 255s on them, going to stick out a little more when I put the 275s in my garage on, but they are for the track only so who cares.
Where in Arizona are you?
If you're in the Phoenix Valley, check out www.clubracingaz.com for NASA road racing!
6/13/08 | 03:12 PM
#4
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From: Arizona
06GT,
Thank you. Actually I am about 185 miles from Phoenix in Sierra Vista. I used to get up to Phoenix when we had the State Autocross championships. Some of my Phoenix autocross friends run the NASA time attacks and such like.
Despite my vigorous driving style, the 285/40 on the front didn't rub with the stock wheels. If I changed to 17" wheels, I couldn't run the stock class. Other than being able to spin the tires at will, the GT500 really has no vices. It is soft fore and aft so you need to manage all that weight transfer.
I still have my Miata for full time autocross duty. Running in our indexed street tires class, I can change cars and still get series points as long as it is on street tires. V700, V710 and all the Hoosiers don’t count as street tires. UTOQ wear rating has to be 140 or better. Autocrossing the GT500 is fun and gets almost as many looks as when I ran my 66 Lincoln Continental in F Stock.
Michael
Thank you. Actually I am about 185 miles from Phoenix in Sierra Vista. I used to get up to Phoenix when we had the State Autocross championships. Some of my Phoenix autocross friends run the NASA time attacks and such like.
Despite my vigorous driving style, the 285/40 on the front didn't rub with the stock wheels. If I changed to 17" wheels, I couldn't run the stock class. Other than being able to spin the tires at will, the GT500 really has no vices. It is soft fore and aft so you need to manage all that weight transfer.
I still have my Miata for full time autocross duty. Running in our indexed street tires class, I can change cars and still get series points as long as it is on street tires. V700, V710 and all the Hoosiers don’t count as street tires. UTOQ wear rating has to be 140 or better. Autocrossing the GT500 is fun and gets almost as many looks as when I ran my 66 Lincoln Continental in F Stock.
Michael
6/13/08 | 05:47 PM
#5
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Not sure what the current "tire to beat" is, but for the past few years the Falken Azeni RT615 has been a pretty consistent one. Same for the Bridgestone RE01's. I think the new kid on the block is the Dunlop Direzza, which is supposed to be a superb tire.
6/13/08 | 06:18 PM
#6
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I have the RE01R on the Miata and they are excellent but I am not sure that 265/35-18 is going to be large enough for the GT500. I have also heard that they are better on lighter cars. A friend of mine is on the Dunlop in a mustang and really likes them. 275/35-18 is their closest size but I might try them anyway.
9/10/08 | 08:58 PM
#8
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06GT,
I can change cars and still get series points as long as it is on street tires. V700, V710 and all the Hoosiers dont count as street tires. UTOQ wear rating has to be 140 or better. Autocrossing the GT500 is fun and gets almost as many looks as when I ran my 66 Lincoln Continental in F Stock.
Michael
I can change cars and still get series points as long as it is on street tires. V700, V710 and all the Hoosiers dont count as street tires. UTOQ wear rating has to be 140 or better. Autocrossing the GT500 is fun and gets almost as many looks as when I ran my 66 Lincoln Continental in F Stock.
Michael
http://www.toyo.com/docs/tires/tires...category=sport
10/28/08 | 04:51 PM
#9
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From: Brookville, PA
Realizing I'm a little late:
The tire to beat IMHO is the Hoosier A6, with the Kumho V710 a close second. Street tires on a heavy, powerful car will get you beaten down on index by lighter cars that don't have the mass or the power down issues of pony-cars, let alone GT500's.
The new breed of Street Touring tires are a great compromise. Those would be things like the RT-615, though it's nothing compared to the RE-01R and Dunlop Direzza Z1.
The tire to beat IMHO is the Hoosier A6, with the Kumho V710 a close second. Street tires on a heavy, powerful car will get you beaten down on index by lighter cars that don't have the mass or the power down issues of pony-cars, let alone GT500's.
The new breed of Street Touring tires are a great compromise. Those would be things like the RT-615, though it's nothing compared to the RE-01R and Dunlop Direzza Z1.
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