Guys, maybe you can help me out, I am perplexed!

I have a '02 Z06 and after having Advanced Induction work my heads and adding a Brain Tooley Racing cam and FAST intake, she put down 456 RWHP.

I am happy with the performance, the only problem is with my typical 395/30/18 square R compound track tire setup, the car can spin the rear wheels in a couple areas on track in 3rd, and that is scary. For optimum acceleration, 3rd gear is usually best in many areas, but breaking the rear end loose when accelerating can be dangerous.


I recently bought a set off Nitto NT01 315/30/18 rear tires thinking that would help keep the rear tires hooked up better, but last weekend when I used them for the first time with 295/30/18 tires in front, I ended up with headaches coming from my traction control system. I like to run in Competitive Mode, but the traction control was coming on all the time until I totally disabled it. I took the 315/30/18s off and put another set of 295/30/18s on back, and the traction control was back to normal, and I ran the rest of the session in Competitive Mode again, but stayed in 4th to keep the rear end hooked up.

The weather was changing rapidly earlier in the day, and my air pressures were too high, and I thought that might have been at least part of the problem, but it seemed like maybe the traction control system was not happy with the larger rear tires.

So after giving this some thought I bought a set of 305/35/18 Nitto NT01 tires for the front, thinking perhaps the slightly different tread compounds might have confused the traction control.


But today I put the Nitto NT01 315/30/18 R and 305/35/18 F tires on, and the same thing happened right away. Now I am concluding the traction control system may not like the different tire diameters, but am really wondering what I can even run.

What variances in tire sizes are acceptable?
Is there a way to reprogram the traction control system?

These tires were not inexpensive, but they seem to have incredible grip. I am hoping to find a way to use them, thanks for any advice or assistance.

Dave

 

And GOD saw that you had a problem, so he deputized HOOSIER to resolve your problem. and yea verily Hoosier has for sale to you, the Hoosier A7! AND, If that doesn't work then MT has on offer the ET Street Radial..............However, I think you will find that after a few dry revolutions that the A7 will hold 3rd gear very adequately

 

I'm surprised you have trouble with the NT01s, traction-wise. I run 295/35-18 Rival in a square setup, and with 449 RWHP, I can hook in 2nd gear once they're warm.

What is your track driving experience level? You may just need to work on throttle modulation.

 

So from the factory, the rear tires are taller than the fronts. so when you put a 305/35/18 on the front, with a 315/30/18 in the rear, you did the opposite. so I'm not surprised the traction control didn't like that.

A lot of track guys run 315/30/18 all the way around. But the 295/30/18 would be ok too with the 315/30/18 rear. (rear would be slightly taller)

I personally did not like having the traction control trying to intervene when on track (even competition mode). I felt like it actually unsettled the car. so I prefer it totally turned off. You might try that for a session or two and see how you like it.

And getting the tire pressures dialed in is very important. I don't run the NT-01's tho so I can't help too much. But close friends have run them and loved them. They can turn some seriously fast laps.

 

I have NT01's and was told to turn TC off on the track...

 

Thanks for the input gents.

After some research and a little trial and error, I found that the issue was the variance in tire diameter. While I don't yet know all the tire sizes that will work together, I can see for certain the tire combinations I had tried did not work together. Apparently some have researched this issue, and found combinations that work with the traction control system, I don't have that list, but if someone can share it, that would certainly be appreciated.

I now know that when running the 315 30 18 Nittos in the rear, I have to run front tires that have an equal or just slightly smaller diameter. I did try another brand of R comp tire in 295 30 18 up front with the 315s in the back, and was able to drive with no traction control issues.

In this case the 315s have a diameter of 25.5", and the 295 diameter is 25", and the traction control system seems to be happy with this combination. Now I wish the Nitto NT01 was available in a 295 30 18 tire, but it is not. Since I can't get a matching set, I may consider the Toyo R888R in 295 30 18 for the front since many say it has the same compound, with only a slightly different tread pattern. It seems reasonable they would use the same compound since Toyo owns Nitto.

I appreciate the recommendation to consider Hoosier tires, I may consider them for the next set of track tires.

Yes, I agree, throttle modulation is important, particularly with these cars. I am very cautious with throttle application, but even still, once the torque has built, I have had the rear slip accelerating out of some corners, and that is scary. I am hoping the 315s will help keep that under control.

I did disengage traction control and was able to run OK, but I had read that running the wrong tire diameters could cause other issues, so I wanted to eliminate that potential problem. Normally I run in Competition Mode which disables the traction control, but keeps the active handling activated, just in case.

 

I race at the Pittsburgh International Race Complex for SCCA Track Nights with my 2001 Z06 with about 625RWHP. I use Nitto 01's on it but I turn all Traction Control off! With this much power and older car electronics, you have to rely upon your track skill to keeps things in order.

 

Hi,

I think this is everything you would need to know about compatible tire sizes for the C5's active handling system to be happy.
https://www.corvetteforum.com/forums...ah-issues.html

Cheers!