Quote:
Originally Posted by NY~FX
I have set of 4 18" x 10.5" Z06 OEM wheels that I intend to use/dedicate to HPDE track sessions on my C5 FRC.
I intend to buy 4 Nitto NT05's for them.
My questions are;
Since the Z06 OEM tire sizes were originally:
Original Equipment Front Size 1: 265/40-17
Original Equipment Rear Size 1: 295/35-18
Specifically:
What size/s should I run with 18's all around - the goal for me is to get increased patch contact in front and allow for larger brakes, and allow for rotation.
How will the choices affect speedometer?
How will the choices affect Active Handling / Traction Control?
How will the choices affect the ratio of heights / stagger?
If I bolster the suspension with coilovers, beefier swaybars, wheel bearings and brakes - what other issues might I need to address to compensate for?
I know this issue has been thrown around before - any concrete answers would be helpful.
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The word from the GM guys is that traction control/active handling is expecting a bias between the front and the rear wheels. If you disturb remove the bias the active handling will engadge.
So. On a stock Z06 the bias is .7 inches or 2.7% larger diameter in the rear tires.
So if you are fixed on the Nitto NT05 then you have one choice. 315 on the back and 285 in the front. These will maintain the bias at .9 which will be fine.
your stagger will be the same...or .2 inches higher in the rear.
Active handling/traction control will not be effected.
Effect on the spedometer is neglidgeable.
Key is to make sure the overal diameter of the rear tires is larger than the front tires. .7 is stock that that is the number you want to try and stay close to.
That being said I run Nitto NT-01s and i have a 0.2 bias to ward the front and I've had no problems with active handling/traction control.
I don't know what the magic bias number is that screws up the handling.....but there is a magic number.
I hope some of that helped.
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Z06 tire size requirements
