Autox and tire discussion

[Norm Peterson]

Originally Posted by WarWolfX0

What about the Nitto Invos, and Vredestein Sessanta
i am looking to keep my cost below $1200 for the tires
but i want to keep the tires for 3 seasons with some autox (5 times this year)
I currently have 20" TSW Nurburgring staggered and am thinking about going with 18" or 19" in the furture.

That Vredestein is still an all-season tire. Even if it is as good as the Michelin Pilot Sport All Season Plus or All Season 3, it still won't be as good at autocross as the summer performance Pilot Super Sport. The PSS in 1LE sizes is $314/tire at Tire Rack as of this morning.

would the side wall flex be a bad thing for the 18"
or is 19" the sweet spot

How willing are you to run smaller diameter tires, keeping in mind such things as the slight lowering, slight increase in tire to fender gap, and slight speedometer error that would occur? None of those really matter much if you're really serious about autocross, but they're things to be aware of.

and is a square setup the best for this car i have been reading and it looks split between square and staggered

Until you're running a forced induction amount of torque, square is better. The car understeers more than you want for autocross, partly because the front end is still the heavy end, and partly because that's still the end that gets the actual turning started. A sluggish start to turning will make you try too hard to bully the car into tuning, and you'll overdrive the smaller tire more easily (think "plowing understeer" when your steering wheel input "outruns" the ability of tire grip to keep up).


Norm

[WarWolfX0]

Is everyone running Pilot Super Sports with 20" rims? or is it worth it to run smaller rims? 19" 18"?

[BullF-16]

Originally Posted by WarWolfX0

Is everyone running Pilot Super Sports with 20" rims? or is it worth it to run smaller rims? 19" 18"?

4 x 19" Forgelines with PSS 305/30 R19s on all 4 corners.

[SPCBA]

Smaller wheels open up more options like falkens in 18. Depending on the rules/classing of your area it can be a be a big benefit. Smaller diameter wheel and tire changes your final gearing...

[WarWolfX0]

O I know about the gears, I have a 3.91 rear gear installed and I had to drive it for a few weeks before gm was able to reset the calibration on my car. I had it installed when I got the 1LE track package.
I would like to keep the diameter of the wheel the same till the 5 year power-train is up. That is when I am going to tune the car.
But I don't want to be buying rims every year.
I am currently running on my winter tires and my summers are the OEM which are worn out.
I need to get a new set this year and I think I might be looking into the PSS now.
I don't mind spending extra on good parts.
I am just a beginner at AutoX.
but the cost of the tires seem to drop when I get smaller tire.
I am hoping that 4 18*9.5 TSW Nurburgring/Interlagos will fit my ctsv brakes
I currently have 20*9/10 TSW Nurburgring.

Originally Posted by BullF-16

4 x 19" Forgelines with PSS 305/30 R19s on all 4 corners.

How wide are your tires?

[BullF-16]

Originally Posted by WarWolfX0

O I know about the gears, I have a 3.91 rear gear installed and I had to drive it for a few weeks before gm was able to reset the calibration on my car. I had it installed when I got the 1LE track package.
I would like to keep the diameter of the wheel the same till the 5 year power-train is up. That is when I am going to tune the car.
But I don't want to be buying rims every year.
I am currently running on my winter tires and my summers are the OEM which are worn out.
I need to get a new set this year and I think I might be looking into the PSS now.
I don't mind spending extra on good parts.
I am just a beginner at AutoX.
but the cost of the tires seem to drop when I get smaller tire.
I am hoping that 4 18*9.5 TSW Nurburgring/Interlagos will fit my ctsv brakes
I currently have 20*9/10 TSW Nurburgring.


How wide are your tires?

305 mm which is 305/25.4 = 12.0 inches. The PSS run wide though, i used to have Bridgestone RE-11 potenzas and though the same 305 width, they were narrower than my PSS by about 3/8" i estimate

My wheels are all 10.5" wide

[sting808]

Here are some 20" options.

Current Street/Rain and my dedicated auto-x wheels:
PSS 285/35R20 (CCW 10")
PSS 295/35R20 (CCW 11.5")
Toyo R888 285/35R20 (TSW 10")

Old street and auto-x set:
NT05 275/45R20 (CCW 10")
NT05 315/35R20 (CCW 11.5")

OE wheel used for reference:
Nitto Invo 275/40R20 (mounted on OE 9" SS)
(Used these on my CCWs for street/auto-x before the NT05)

Last 2 days with the newly mounted PSS on the street has been great. Best tires I've tried between P-zero, Invo, NT05, and R888 for street. Quiet and grippy. We'll see what happens on the next rain day race. In hindsight, the only good thing about the Nittos is they're cheap.

The Rival tread pattern and contact patch looks like they may be noisy on the highway. I want Hoosier A6s in 285/35R20.

[woodside783]

Originally Posted by BullF-16

4 x 19" Forgelines with PSS 305/30 R19s on all 4 corners.

The best set up for all out

[WarWolfX0]

So I was thinking of going with Michelin Pilot Super Sport on my 20" rim.
but they don't make them for my front 9" wide rim.

Looks like I am going to ether buy 2 20x10" TSW Nurburgring for the front
or maybe go with 19x10.5 Nurburgring

Forgelines seem a little much for me
The cost of just the rims alone looks to be equal to 4x19x10.5 Nurburgring with PSS

According to my math the 19x10.5 Nurburgring will only be 2mm towards the inside on the front and 12/14mm further out then my 20x9/10 setup.

[woodside783]

you will like the way it handles if you do that

[Synner]

I can say that a 295 MSS in ferrari spec is 3" wider than the stock front tire on a 10.5" wide rim. The aggressive fitment may not be for everyone though. I will need a warmer track day to really stretch their legs, the first one was 35 degrees lol.

[WarWolfX0]

I have been doing some math
so I am currently running a 3.91 rear gear (GM installed) comming from a 3.75
with the 305/30/19 it would be like running a 3.84 rear gear on stock setup
or for me getting these tire would feel like a 4.0 rear gear. This would also through off my mph by .09 per mph (speedo needs to show 60 but i will be doing 55)
Also theses tire would drop the car 1.25" from stock

[Todd in Vancouver]

Great idea for a thread.

With all the discussion on tires thought I'd throw another subject in here. AutoX really gets going next month locally so I'm off to Drivers Training in a week to brush up on my driving skills. Fact is my ZL is more capable then my driving skills are so all the horse power and tire in the world isn't going to make me any faster until I get better at driving. Just something to think about as we all head into racing season before everyone spends more cash on the cars it might be a better investment in yourselves.

[Gen52SS]

Originally Posted by Todd in Vancouver

Great idea for a thread.

With all the discussion on tires thought I'd throw another subject in here. AutoX really gets going next month locally so I'm off to Drivers Training in a week to brush up on my driving skills. Fact is my ZL is more capable then my driving skills are so all the horse power and tire in the world isn't going to make me any faster until I get better at driving. Just something to think about as we all head into racing season before everyone spends more cash on the cars it might be a better investment in yourselves.

I agree +1