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305/35/19 tires on 19x10 wheel + autocross

WildHorse

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As the title states, that's what I have. It bulges a little. I thought not enough to adversely affect the cars handling at our local 1.6 mile autocross. However, I definitely noticed the sidewall trying its damndest to fold over on itself (32psi cold pressure). Got kinda outta hand on the harder turns. Next set of rears will be 285/35r19's. Should be a better fit for the 19x10 wheels correct? :cheers:
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5pointOh

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As the title states, that's what I have. It bulges a little. I thought not enough to adversely affect the cars handling at our local 1.6 mile autocross. However, I definitely noticed the sidewall trying its damndest to fold over on itself (32psi cold pressure). Got kinda outta hand on the harder turns. Next set of rears will be 285/35r19's. Should be a better fit for the 19x10 wheels correct? :cheers:
305 needs at least a 10.5" rim. 285 will be perfect
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BmacIL

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285/35R19 is a perfect fit on a 10". That said, generally for autocross you want as wide as you can fit. 295 is tough to come by, so 285 is a good choice.

Your pressures are too high, for one thing. You want the rears around 31-32 hot, not cold, and the front about 35-36 hot if you don't have added camber. What is your suspension setup and alignment, as well as what tires? If you have a stock suspension/chassis, non-PP GT, there's a whole host of reasons it was having that behavior. The base GT is a sloppy mess stock (I know firsthand).
 
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[MENTION=10281]BmacIL[/MENTION] Yeah.. bonestock GT suspension & alignment. Tires are Goodyear eagle RS A2 fronts (245/45r19 surprisingly grippy) and nitto NT05R rears.
 

BmacIL

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[MENTION=10281]BmacIL[/MENTION] Yeah.. bonestock GT suspension & alignment. Tires are Goodyear eagle RS A2 fronts (245/45r19 surprisingly grippy) and nitto NT05R rears.
And that's where your feeling of losing it/folding over came from. Those drag tires are not really meant to corner spiritedly. They have very soft sidewalls. If you decide autocross is something you're more than very casually interested in, a square tire setup with summer performance tires (rather than an A/S and a drag radial) is the key to getting the car to work. My 19x9.5 square setup with 275 width RE71Rs is awesome to drive.
 

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[MENTION=10281]BmacIL[/MENTION] front wheels are 19x9.. rather keep those the buy another set lol. But otherwise yes, I wanna get serious about road course racing.
35298423_1743772229051068_448588533540585472_o.jpg
 

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[MENTION=10281]BmacIL[/MENTION] front wheels are 19x9.. rather keep those the buy another set lol. But otherwise yes, I wanna get serious about road course racing.
35298423_1743772229051068_448588533540585472_o.jpg
Nice. 275/35R19 all around is a good combo.
 

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As you progress into a better driver and ultimately become more serious with AutoX and track driving, you will want to make the switch to a square setup like BmacIL mentioned. I would do 19x10" all around with a 285/35-19 or even 275/35-19, making sure you have the same tire at both ends as well. Something like the Continental ExtremeContact Sport is a great option for a tire that can pull off dual duty (street and track/AutoX), as is the class leading Michelin Pilot Sport 4S.

Our 19x10" ET40 EC-7 bolts on without any spacers, and is currently on sale in the Race Silver finish if you're looking to add a second set soon!

I wouldn't consider buying any new wheels that aren't at least 10" wide for handling purposes.
 

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As you progress into a better driver and ultimately become more serious with AutoX and track driving, you will want to make the switch to a square setup like BmacIL mentioned. I would do 19x10" all around with a 285/35-19 or even 275/35-19, making sure you have the same tire at both ends as well. Something like the Continental ExtremeContact Sport is a great option for a tire that can pull off dual duty (street and track/AutoX), as is the class leading Michelin Pilot Sport 4S.

Our 19x10" ET40 EC-7 bolts on without any spacers, and is currently on sale in the Race Silver finish if you're looking to add a second set soon!

I wouldn't consider buying any new wheels that aren't at least 10" wide for handling purposes.
What are the chances you produce the ARC-8 (deep concavity) for a S550 Mustang fitment?
 

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What are the chances you produce the ARC-8 (deep concavity) for a S550 Mustang fitment?
Very slim. Mustangs use a unique hub setup that makes it challenging to get a wheel to not only clear the caliper, but also not poke way out. Same reason why our EC-7 use the medium concavity design instead of deep. Plus adapting the ARC-8 to fit S197 and S550 cars would require a big redesign that would add a lot of weight.

The ARC-8 is a lovely wheel, but just not going to happen on Mustangs right now unfortunately.

- Cory
 

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If you put a camera on the tires, autocross is going to cause most tires to squirm an uncomfortable amount if they're square or wider than the wheel.

Stiffer sidewall tires and/or higher PSI will help. Yours may need more than 32 cold.

About the only thing you can do to really reduce it is stretch the tire onto a wider wheel than typical. Even then they're going to shift as much as they can.

Just because a tire is moving around isn't the most terrible thing. You still may be getting better grip out of the wider tire. If its rolling over and riding on the sidewall instead of the tread, that's bad (increase PSI). If the tire is squiring around you're transitional handling may be a little funky, but if you're smooth with the inputs it shouldn't be a huge deal.
 

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Very slim. Mustangs use a unique hub setup that makes it challenging to get a wheel to not only clear the caliper, but also not poke way out. Same reason why our EC-7 use the medium concavity design instead of deep. Plus adapting the ARC-8 to fit S197 and S550 cars would require a big redesign that would add a lot of weight.

The ARC-8 is a lovely wheel, but just not going to happen on Mustangs right now unfortunately.

- Cory

sigh!... Well, do you have any upcoming new wheel designs/color finishes for the S550?
 

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If you put a camera on the tires, autocross is going to cause most tires to squirm an uncomfortable amount if they're square or wider than the wheel.

Stiffer sidewall tires and/or higher PSI will help. Yours may need more than 32 cold.

About the only thing you can do to really reduce it is stretch the tire onto a wider wheel than typical. Even then they're going to shift as much as they can.

Just because a tire is moving around isn't the most terrible thing. You still may be getting better grip out of the wider tire. If its rolling over and riding on the sidewall instead of the tread, that's bad (increase PSI). If the tire is squiring around you're transitional handling may be a little funky, but if you're smooth with the inputs it shouldn't be a huge deal.
Honestly there's not much he can do about that with a drag radial. They'll fold over beyond 6 tenths.
 

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285/35-19 Conti EC Sport square tires handling track duty no problem...


[ame]

The Conti's are the best value in the size. I paid almost $400 less than the Michelin PS4s at the time; easy decision.
 

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