Tire pressures for Firehawk Indy 500 tires for track/autox

[EFI]

Why not? The point is to learn how to maximally utilize what you have. Not overcompensate with bigger/stickier rubber that you're not good enough to stress.

Because you're not really learning track driving skills by skating around 235 all seasons. Sure you're learning important car control skills that will be useful in day to day driving, but that won't exactly be relevant on a track when your goal is to set fast lap times. It might be good if you're practicing for drifting events though.

Let me put it this way, if you "learn" your car on 235 all seasons, then slap on some 295+ summer tires and you head back to the track you're going to have a whole new animal on your hand and have to "learn" it ALL over again.

And once again, you don't have to be anywhere near a pro to be able to use 295 200TW tires on a track. If you're just out there doing parade laps and practicing to drive Miss Daisy (absolutely nothing wrong with that) then I guess those tires would be sufficient. But if you're at all trying to be competitive, or learn how to handle your car on a track and get better, then those are basically useless.

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[NightmareMoon]

I never even knew about the wear indicators on the tires for roll over scrub. Does the PS4 have them? I was looking and didn't see any.

Yes, they do. Look for this little J hook thing if you haven’t worn it off already.

Treadwear indicators are just useful to make sure you aren’t too far off. Track rats will want to experiment with pressures and check temperatures across the tread to find the most grip.

 

[shogun32]

that won't exactly be relevant on a track when your goal is to set fast lap times

that's YOUR goal. Learning the car, reading how it responds, how to pick up on approaching limits. Those are mine. That's the point of High performance driving EDUCATION. Lap times are only a criteria in racing and as a secondary means to measure skill improvement.

have to "learn" it ALL over again.

so what?

 

[EFI]

that's YOUR goal. Learning the car, reading how it responds, how to pick up on approaching limits. Those are mine. That's the point of High performance driving EDUCATION. Lap times are only a criteria in racing and as a secondary means to measure skill improvement.

You mention intermediate groups, autocross and faster lap times. And then you mention the tires are becoming an issue. I don't think pressure is your issue, what I'm saying is that you're getting to a point where your out driving those skinny hard tires. Which is why I mentioned stepping up to a better and wider tire. You can play with airpressure all you want on those, but that won't make up for the inherent shortcomings of a 235 340TW street tire.

If you want to have fun and learn your car with those, sure they are more then adequate. But you came in here saying they're becoming an issue, and all we're trying to tell you is that it's not an air pressure issue but lack of contact patch and grip for the size car and for your growing skills pushing the car harder and harder.

 

[PoppinJ]

Yes, they do. Look for this little J hook thing if you haven’t worn it off already.

Treadwear indicators are just useful to make sure you aren’t too far off. Track rats will want to experiment with pressures and check temperatures across the tread to find the most grip.

Thank you so much, I never knew. My fronts are definitely worn off. I can see one or two very faintly, the rears line up perfectly with the wear line. I run -2.0 camber up front with a hot psi of 35, 285/35/19 on 10 in wide rim. I'm assuming since the tire is rolling over to much I should boost the pressure to 37ish to see if that helps?

 

[BmacIL]

Thank you so much, I never knew. My fronts are definitely worn off. I can see one or two very faintly, the rears line up perfectly with the wear line. I run -2.0 camber up front with a hot psi of 35, 285/35/19 on 10 in wide rim. I'm assuming since the tire is rolling over to much I should boost the pressure to 37ish to see if that helps?

Yes. If you can get more camber, or more roll stiffness, that would be better though.

 

[PoppinJ]

Yes. If you can get more camber, or more roll stiffness, that would be better though.

Next alignment I may try -2.5 camber but not sure if I'll ever get around to it. Currently running FP track pack suspension with saway bars on stiff. Not sure if I'll ever do anything more extreem. I may get the steeda extended lateral link and bumpsteer kit but thats about as far as im currently willing to go. The next step is prob cup2s or re71r dedicated track tires. If I went from a 285/35 to a 285/30 that might help as well would it not?

 

[BmacIL]

Next alignment I may try -2.5 camber but not sure if I'll ever get around to it. Currently running FP track pack suspension with saway bars on stiff. Not sure if I'll ever do anything more extreem. I may get the steeda extended lateral link and bumpsteer kit but thats about as far as im currently willing to go. The next step is prob cup2s or re71r dedicated track tires. If I went from a 285/35 to a 285/30 that might help as well would it not?

Changing aspect ratio would not really do much. Also, while I do like them quite a bit, the steeda lateral link will narrow your track width and reduce the max camber possible.

 

[PoppinJ]

Changing aspect ratio would not really do much. Also, while I do like them quite a bit, the steeda lateral link will narrow your track width and reduce the max camber possible.

I figured the reduced height sidewall would help stiffen the tire up and make it less prone to rolling over. Difference in 285/30 and 285/35 is over an inch shorter overall (12.8 percent shorter sidewall). Same with going from a 285 to a 275 on the sime size wheel. Helps stretch it out a bit to stiffen it up.

 

[BmacIL]

I figured the reduced height sidewall would help stiffen the tire up and make it less prone to rolling over. Difference in 285/30 and 285/35 is over an inch shorter overall (12.8 percent shorter sidewall). Same with going from a 285 to a 275 on the sime size wheel. Helps stretch it out a bit to stiffen it up.

It may help some, but going to a tire with stiffer construction would do much more. RE71Rs, for instance, can be run closer to -2.0 up front and not roll over much, even at relatively low pressures (30-32 hot).

 

[NightmareMoon]

Thank you so much, I never knew. My fronts are definitely worn off. I can see one or two very faintly, the rears line up perfectly with the wear line. I run -2.0 camber up front with a hot psi of 35, 285/35/19 on 10 in wide rim. I'm assuming since the tire is rolling over to much I should boost the pressure to 37ish to see if that helps?

Too much pressure and grip will fall off anyway, and 37 probably won't be better for grip. Since your hot pressures are close (maybe try 36, but its not going to help much), the main issue here is 2.0 degrees is just not nearly enough front camber on our cars to prevent early shoulder wear if you're autoxing or tracking the car. You need closer to 3 degrees if you want to keep the shoulders alive.

A temperature measuring tool will help you see whats happening. If the center is too cold and the inside and outside of the tread are hotter and equal temps, then more pressure will help, but if the outside shoulder is hotter than the inside, then more camber is what you really need.

 

[GJarrett]

Thise cold pressures are way too high in my opinion. If I started there, I'd be 43 plus hot and it would be like skating.

Then again I'm in Texas and drive like an idiot.

As far as when to check? Unless you have a 2nd or 3rd person check them in hot pit, you can only check when you park...that's when I do it.

I have noticed that the psi reading on my dash is very accurate, to the point that I have started trusting that for checking my tire pressures most of the time.

 

[bullitt2]

You mention intermediate groups, autocross and faster lap times. And then you mention the tires are becoming an issue. I don't think pressure is your issue, what I'm saying is that you're getting to a point where your out driving those skinny hard tires. Which is why I mentioned stepping up to a better and wider tire. You can play with airpressure all you want on those, but that won't make up for the inherent shortcomings of a 235 340TW street tire.

If you want to have fun and learn your car with those, sure they are more then adequate. But you came in here saying they're becoming an issue, and all we're trying to tell you is that it's not an air pressure issue but lack of contact patch and grip for the size car and for your growing skills pushing the car harder and harder.

I am having to adjust the pressures is what I meant by that. Not really an issue. The car is getting driven harder, as such I'm having to adjust the pressures during a track day which is what I am inquiring about. The 235 width has been fine for now. When I burn through those tires, I have a set of performance pack Michelin tires/rims to put on

 

[17LightningGT]

I went to an autox event last weekend, and i recently had the indy 500 mounted on my spare set of PP wheels to use as a dedicated cheap autox tire.

275/40/19 front and rear, it was about a 75 degree day, and the course is concrete.

I started off with cold pressure at 32. the tires were brand new so they had some breaking in to do. I found that once they got warmer and pressures increased, they started to squeal and lose grip.

I took a white paint marker and marked from the tread, down the sidewall to track how far it was rolling over. At 35PSI or so hot, they were still an inch or so away from the sidewall. At that point i was running 50.5 second laps.

I dropped the pressure down to 32 hot, and the tread usage started to get closer to the sidewall, the tires stopped squealing as bad, and my times started to improve. I was running progressively faster and my times went down to 48.8 or so.

I believe that the indy 500 need some heat in them to start gripping, and depending on your wheel and tire size, seem to like a little lower temperatures as well.

 

[Cardude99]

I went to an autox event last weekend, and i recently had the indy 500 mounted on my spare set of PP wheels to use as a dedicated cheap autox tire.

275/40/19 front and rear, it was about a 75 degree day, and the course is concrete.

I started off with cold pressure at 32. the tires were brand new so they had some breaking in to do. I found that once they got warmer and pressures increased, they started to squeal and lose grip.

I took a white paint marker and marked from the tread, down the sidewall to track how far it was rolling over. At 35PSI or so hot, they were still an inch or so away from the sidewall. At that point i was running 50.5 second laps.

I dropped the pressure down to 32 hot, and the tread usage started to get closer to the sidewall, the tires stopped squealing as bad, and my times started to improve. I was running progressively faster and my times went down to 48.8 or so.

I believe that the indy 500 need some heat in them to start gripping, and depending on your wheel and tire size, seem to like a little lower temperatures as well.

That's a good idea. I'm going to try that come fall thanks

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