Tire recommendation for HPDE

[tosha]

there is no such thing as 'enough' rubber for FI short of tall-sidewall drag radials and even then. If you like to do track work FI will IMO ruin the car.

Interesting.. do you think it would be too hard to modulate throttle? I realize that I won't be flooring it and need to be careful with gas pedal unless maybe in long straights, but would that be really unusable?
Some suspension mods are in the plan as well. Camaro zl1 seems to be a great track car with similar power. Yes, it's completely different chassis but still, big power is there and it's not too much.

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[Norm Peterson]

The Camaro ZL1 only runs 20 mm of tire stagger with a 1" difference in rim width. The non-1LE ZL1 also has a 1" wheel diameter difference for some odd reason. 20 mm of stagger seems like a decent place to be for adding rear grip without bringing on a bit too much limit understeer.

ZL1 1LE
305/30ZR19 98Y 11Jx19 ET11
325/30ZR19 101Y 12Jx19 ET41

ZL1
285/30ZR20 95Y 10Jx20 ET20
305/30ZR20 99Y 11Jx20 ET43


Norm

 

[Norm Peterson]

A useful site for finding OE wheel and tire sizes

Wheel-Size.com :: Reference guide for car wheel and tire dimensions such as size, offset, PCD


Norm

 

[shogun32]

do you think it would be too hard to modulate throttle? I realize that I won't be flooring it and need to be careful with gas pedal unless maybe in long straights, but would that be really unusable?

depends on the nature of how the blower makes power. Even minor throttle produces a ton of torque. I'm sure you could make it work but it'll complicate life and the learning process and you may never be able to use the full power which begs the question - what's the point?

The ZL1 makes good power, sure but it's HOW it makes power that seems to be more track and driver-friendly.

 

[strengthrehab]

Studs/spacers are fine for daily driving.

 

[TeeLew]

The Camaro ZL1 only runs 20 mm of tire stagger with a 1" difference in rim width. The non-1LE ZL1 also has a 1" wheel diameter difference for some odd reason. 20 mm of stagger seems like a decent place to be for adding rear grip without bringing on a bit too much limit understeer.

I know there is a big debate internally at GM about what 'looks correct' on a muscle car. The wider rear tire is as least as much about appearance as it is about performance & probably more.

 

[Norm Peterson]

I'm sure that similar discussions have gone on at Ford.

Still, it does seem that 20 mm stagger is a good place to stop where handling performance has at least equal weight with appearance. For forced induction front engine/RWD cars, anyway.


Norm

 

[tosha]

The Camaro ZL1 only runs 20 mm of tire stagger with a 1" difference in rim width. The non-1LE ZL1 also has a 1" wheel diameter difference for some odd reason. 20 mm of stagger seems like a decent place to be for adding rear grip without bringing on a bit too much limit understeer.

ZL1 1LE
305/30ZR19 98Y 11Jx19 ET11
325/30ZR19 101Y 12Jx19 ET41

ZL1
285/30ZR20 95Y 10Jx20 ET20
305/30ZR20 99Y 11Jx20 ET43


Norm

Hi Norm,

Was really hoping to get a response from you, really great posts with technical details. So, would you go with mild stagger (285/305) in my case?

 

[tosha]

Studs/spacers are fine for daily driving.

Agreed. What is not fine with me for daily driving is the amount of front wheel poke with 305 wheels, that I've seen on PP2. 52 offset with 25mm spacer would give very similar picture. I'm ok with it on track though.

 

[Norm Peterson]

Hi Norm,

Was really hoping to get a response from you, really great posts with technical details. So, would you go with mild stagger (285/305) in my case?

I'd start there, as there's some OE weight behind that much being enough, at least with sane amounts of throttle tip-in response. Dragstrip and street challenge levels of tip-in response would be the wrong direction to send that part of your car's development off in.


Norm

 

[Norm Peterson]

Agreed. What is not fine with me for daily driving is the amount of front wheel poke with 305 wheels, that I've seen on PP2. 52 offset with 25mm spacer would give very similar picture. I'm ok with it on track though.

Province regulations and pebble-throwing aside, it's a look that you can actually get used to because it is right for the car's and your hardest driving. Just sayin' . . . scroll my sig pic down a bit).


Norm

 

[tosha]

depends on the nature of how the blower makes power. Even minor throttle produces a ton of torque. I'm sure you could make it work but it'll complicate life and the learning process and you may never be able to use the full power which begs the question - what's the point?

The ZL1 makes good power, sure but it's HOW it makes power that seems to be more track and driver-friendly.

Thanks. I guess I will try it and will share the experience . Roush SC is described as very progressive, so hope it would still work.

To answer the question about the point - I just want to have this experience in life of owning such car.

But from track performance perspective, having access to more power and torque across the rev range should not be a bad thing. You don't have to be flatting out all the time, but you know that 2021 MT82 has pretty long gears. I was on the track last weekend, where most of it is in 3rd gear (except for straights) and there was no reason to go to 2nd, but while exiting from some turns, I was craving for more power, as the car was gradually revving through the range. Didn't want to switch back and forth either.

I guess I should have mentioned manual at the start

 

[NightmareMoon]

I'd start there, as there's some OE weight behind that much being enough, at least with sane amounts of throttle tip-in response. Dragstrip and street challenge levels of tip-in response would be the wrong direction to send that part of your car's development off in.


Norm

Meh. The S550 chassis needs the front 305 tire to turn well on track. I’d be ok with a 305/315 or something but 10mm isn’t worth loosing the ability to rotate IMHO.

The 1LE Camaro doesn’t have as much room in the front wheel wells to shove a 305 in there without tearing up the fender liners, which might have more to do with why you don’t see more 305s on the front of those cars.

The issues with a blower on track aren’t so much about controlling the power (that part is just good fun), but what it actually takes to cool the extra heat generated. Its no fun to get 2 good laps and then have to pit or drive like a granny to cool it back into reasonable temp range. Also you’d need a lot of brakes to shed the extra speed. Take a look at the GT500 brake calipers and rotors.

285/35 (or 275/35) if you want to get your money’s worth, but I’d want 305 square myself for the track. 305 is definitely overkill for the street.

I wouldn’t choose smaller front tires to control oversteer personally. I would select swaybars to control oversteer tho.

 

[tosha]

I'd start there, as there's some OE weight behind that much being enough, at least with sane amounts of throttle tip-in response. Dragstrip and street challenge levels of tip-in response would be the wrong direction to send that part of your car's development off in.


Norm

Thanks, will probably go that route. At least it will be easier to throw wider wheels at the front later on, if need be.

 

[shogun32]

The 1LE Camaro doesn’t have as much room in the front wheel wells to shove a 305 in there

because of the *retarded* spring perch location.

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