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Autocross racing tyres/sizes etc?

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Old 05-17-2018, 05:17 PM   #1  
corvettedave383
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Default Autocross racing tyres/sizes etc?

Ive got 335/30/18 in the rear and 285/35/18 up front in normal road tyres, want to do some racing autocross style

can get Toyo R888 in 335/30/18 size no problem, but would like r888 up front too, this is where the problem starts, you cant get 285/35/18 in the r888, you can get 275/35/18, but they are alittle smaller, 25.6 inches, the 285 are 25.9 inches or could get 295/35/18, but there alittle bigger, 26.1

so is it best to go wider/taller(295) up front or smaller/thinner up front(275)?

or another option is another tyre brand up front, got to stick with r888 at rear, there about the only company in the Uk, doing that 335 size in a racing tyre

or another option could be put on Michelin Pilot Super Sport, which come in the correct 285 size

thoughts??
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Old 05-17-2018, 06:54 PM   #2  
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I would go wider and taller. It also comes down to your wheel width. I have 10 inch and installed 295 Hoosier R1s front and 335 rear on 13 inch

With my setup and rear weight bias I never had front end push. Understeer

ensure that you have them filled with nitrogen and get a thermal reading gun to help you figure out tire pressure and alignment settings
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Old 05-18-2018, 01:32 PM   #3  
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Originally Posted by gkull View Post
I would go wider and taller. It also comes down to your wheel width. I have 10 inch and installed 295 Hoosier R1s front and 335 rear on 13 inch

With my setup and rear weight bias I never had front end push. Understeer

ensure that you have them filled with nitrogen and get a thermal reading gun to help you figure out tire pressure and alignment settings
ok good info, do you think you would notice the size diference between rear and front been alittle bigger when looking at car? thoughts
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Old 05-18-2018, 03:02 PM   #4  
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When I see a car with big racing tires, I just think that the car looks bad ***. Never about Aesthetics.


I found 650 or 700# front QA1 coil overs were about the best for light front end The local track had big rumble strips on the inside of some of the turns and I could really use them to straighten out the track. 1 1/8th saw bar with spring end links. so the bar was free for small amounts of vertical wheel movement
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Old 05-18-2018, 03:06 PM   #5  
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Originally Posted by gkull View Post
I would go wider and taller. It also comes down to your wheel width. I have 10 inch and installed 295 Hoosier R1s front and 335 rear on 13 inch

With my setup and rear weight bias I never had front end push. Understeer

ensure that you have them filled with nitrogen and get a thermal reading gun to help you figure out tire pressure and alignment settings
Why R1's and not A6's or 7's?
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Old 05-18-2018, 04:02 PM   #6  
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Originally Posted by gkull View Post
When I see a car with big racing tires, I just think that the car looks bad ***. Never about Aesthetics.


I found 650 or 700# front QA1 coil overs were about the best for light front end The local track had big rumble strips on the inside of some of the turns and I could really use them to straighten out the track. 1 1/8th saw bar with spring end links. so the bar was free for small amounts of vertical wheel movement
dont mind them been wider, just worried incase they look taller than the rears
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Old 05-18-2018, 04:49 PM   #7  
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Why R1's and not A6's or 7's?
A stands for autocross with Hoosier tires.

Auto-X is for people still in grade school I was a road racer from an early age. Later on a job transfer took me to an area where SCCA only did Solo competition because of the distance to RR tracks.

Solo racing wore me down traveling to all the divisional meets. Typical day from memory from about 25 years ago beginning at 8 am was checkin/tech to make sure that you were competing in the correct class. then a free time stroll around the track to memorize it. Split you into three run groups. driving on the track group, working the track group, prepairing to drive group.


You could be there all day long and you would get one practice and then go work the track. Then a timed run and go work the track and the final timed run and cycle through everybody. Most tracks were setup got the best times maybe in the high 40 seconds on down to the family pickup doing 70+ seconds. So your typical day for me was 3 runs of under 60 seconds each total for the whole day. It cost about $25 dollars entry, travel, and lodging for out of town events. I won some events in my class and did okay in the season points standings. I did BSP BP in my vette and my winning 2 liter car was in something like FS class. All that time and effort for under three minutes just sucked I did it, I won, and it wasn't that much fun.


Road racing was usually about $150 per day and you could get anywhere from 20 minute or even 30 minute run groups for practice, qualifying, and then for the race.


So it was boring to spend a whole day and only do three 56 second runs. Where road racing was 60 to 90 minutes of track time. or test an tune days where you could get many hours of track time if you wanted to. or even enter 6 and 24 hour events with a team of drivers driving one car or motorcycle.
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Old 05-18-2018, 05:42 PM   #8  
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A stands for autocross with Hoosier tires.

Auto-X is for people still in grade school Ooooh, low blow
The OP's Title and very first sentence mentions auto crossing. The A series is much stickier but wouldn't hold up long if he wants to road race. So yes perhaps your off topic digression about how much you love road racing and why also deserves some discussion as to the differences between road racing and autocross tires. He is otherwise ill advised to compete in AutoX on R series against the stickier tires..

Last edited by ignatz; 05-18-2018 at 05:42 PM.
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Old 05-18-2018, 07:21 PM   #9  
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Quote:
Originally Posted by ignatz View Post
The OP's Title and very first sentence mentions auto crossing. The A series is much stickier but wouldn't hold up long if he wants to road race. So yes perhaps your off topic digression about how much you love road racing and why also deserves some discussion as to the differences between road racing and autocross tires. He is otherwise ill advised to compete in AutoX on R series against the stickier tires..
I just use the autocross name because if i say track racing, usual everyone in the USA , thinks drag track, but iam talking about racing around circuit track, like say "Road America" and its not really about brand of tyre, its more the size difference issues

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Old 05-18-2018, 07:57 PM   #10  
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I don't think that many people can look at 25.9 rear and a 26.1 and see a visible difference especially when the rear is so much wider.

I've probably had taller front than rears for many years, but they are still shorter that the original 255/60/15's
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Old 05-19-2018, 04:08 AM   #11  
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I don't think that many people can look at 25.9 rear and a 26.1 and see a visible difference especially when the rear is so much wider.

I've probably had taller front than rears for many years, but they are still shorter that the original 255/60/15's
ok good info, the old 255/60/15 work out at 27 inch, which is alot bigger
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Old 05-19-2018, 07:58 AM   #12  
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I'd go with Hoosier A8's if you're not using them on the street.
http://hoosiertire.com/assets/Circui...5%207%2018.pdf
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Old 05-19-2018, 10:54 AM   #13  
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gkull, you nailed all the points on why I stopped going to my local SCCA solo events. I can't give up an entire day with my family for 3 minutes of race time.

I don't understand whose who do it. I put in a good effort and had some fun at first but after 6-7 events I was done.

The last straw was when the night event, which only cost a later afternoon/evening, not the whole day, imposed a decimal limit which my side piped roller cammed 355 blasted beyond, requiring me to short shift.

I wouldn't mind getting on a road racing track. Spring mountain is nearby. Someday I'll get involved with a club and run it.

You guys are making me feel inadequate with my 255/45ZR18 continentals and my simple street and slalom suspension, but it does alright. Definitely better than stock.

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