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Hi, I am getting ready for 2014 Autocross season and I am planning on getting A6 Hoosiers.
205 front and 245 back. Any advice on which tire shoulder design should I choose- square or round?
My elise is supercharged and I have wheel spacers in the back so I was able to run R888 225 front and 255 back with minimal rubbing. Suspension has nitron singles which are height adjustable.
Any advice would be highly appreciated!
Thanks
 

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Square tires for drag racing and round tires for cornering?

I didn't know I had a choice.
 

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i didnt know you could choose either. Cool. Having no backgound on this I would guess. Round for camber challenged cars and square for cars with good camber curves or lots of static negative camber.

It seems like you would be in at least ssp or higher and square shoulds with appropriate camber mods would be preferable, but I anxiously await discussion from the experts
 

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I don't think you get a choice. At least not at tire rack. Get the heat cycling if they offer it.
 

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I don't think Hoosier offers a choice. Might you be thinking about the Kumho V710?

dave
 

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Not quite sure if I understand your question... square or round. Are you referring to a stretched tire? For cornering, you want a slightly stretched tire... Stretching a more narrow tire over the rim... Meaning you have more tread on the track. The more rounded the tire shoulder looks, the more it should be able to stretch over a narrower rim. 225/45/17 is stock... 205/40/17 would be my suggestion for autocross... But that only gives you the R6's, not the A6's... Smallest I see the A6 is a 225/40. A6 goes flat after 10-ish heat cycles. The V710 comes in a 215/40 but is closer to the R6 than the A6. The A6 is super sticky! You may tip the car over in a tight corner! Fun!
 

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Tip the car over........Not really. It honestly takes a lot to tip a car over, especially in autox.

I used A6's on my first track day in July heat. They stuck like gum for the weekend but I burned them out in 2 days. My next autox with the wife and I both driving the car finished them and she beat me that weekend being used to R comps on her Elise.

If your just doing autox once a month you will get 6 months out of them.

I'm not a tire Guru, but it depends on your driving style and heat cycles. You will in time start feeling when they fall off. When that happens its time for a new set. It takes a while to know them. Im still trying to figure out R6's.
 

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I believe the main advantage to tire shaping is the net effective camber for class limited cars. You always want to have as much rubber on the road as you can. Camber compromises straight line grip to have a more square contat patch on the outer wheel during cornering.

About a decade ago a had a conversation over beer with a couple autocross gurus. We concluded that if hoosier ever decided to make a cone shaped tire with a 3-4 degree taper, it would change the game for stock class cars (that have limited camber adjustment). It would also be terrible for the sport because you would have tires that cant be flipped and wouldnt last many runs.

A more rounded profile tire would accomplish a similar goal to a lesser degree but with lesser compromises as well. Note that I am not sudgesting pinching a tire on a narrow rim will achieve this effectively. That is sorta like choping off your arm to lose weight. It works but doesnt achieve the desired effect.
 

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We already had tires that worked on camber-deprived cars and could not be flipped: They were called BFG Comp T/A R1. They did it by having a seriously-stiff sidewall on the inside and a softer sidewall on the outside.

Figures that they were what I could get for my Europa, which did not need this feature, and now that I have a camber-deprived Elise, they are no longer made...

I believe the main advantage to tire shaping is the net effective camber for class limited cars. You always want to have as much rubber on the road as you can. Camber compromises straight line grip to have a more square contat patch on the outer wheel during cornering.

About a decade ago a had a conversation over beer with a couple autocross gurus. We concluded that if hoosier ever decided to make a cone shaped tire with a 3-4 degree taper, it would change the game for stock class cars (that have limited camber adjustment). It would also be terrible for the sport because you would have tires that cant be flipped and wouldnt last many runs.

A more rounded profile tire would accomplish a similar goal to a lesser degree but with lesser compromises as well. Note that I am not sudgesting pinching a tire on a narrow rim will achieve this effectively. That is sorta like choping off your arm to lose weight. It works but doesnt achieve the desired effect.
 

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Yes it is the Kumho Ecsta V710 no Hoosier that come in round or square corner versions, but for most sizes it is an either or as many are not offered.
 
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