dbjeng

Here's the situation: Street car about 4k miles/year and 2-3 HPDEs per year. Been doing HPDEs since 1990 in Vettes and other cars, autocrosses since 1974.

My bone stock 01 Z06 has standard 9.5x17 fronts and 10.5x18 rear original wheels and GY supercar tires. For a bit of economizing, best value situation, I was thinking about running 275 or 285/40-17s on 9.5x17 wheels on all 4 corners. Nitto NT05s would be very inexpensive in this setup.

As we all know, this car is very powerful, so running the stock supercar tires and wheels I never find myself trying to lay the pedal to the metal coming out of a corner anyway as it'll get sideways - allways rolling the throttle and testing the limits. It seems to me that losing 1 tire size or 2 (from 295 to 285 or even 275 on the rears) shouldn't be that big of a deal.

Has anyone tried this setup? Is there a problem with the computer sensing the size difference? Any reason this would not work nicely?

It seems to me a square setup is a naturally better handling arrangement for a near 50/50 weight ratio car like the vette. Seems that Chevy puts the wide/narrow arrangement to build in a little understeer for safety/lawsuits. I've considered 11x17 on all 4 corners w/ 315/35-17s all the way around but that's real expensive. I can't really afford 2 sets of wheels and tires so I'm looking for the best compromise. Seems consensus is pretty much the NT05s for tires.

Nitto NT05 - 275/40-17 $160, 315/35x17 $226

Even been considering the Firestone wide oval tires.

Thoughts and experience on these ideas would be appreciated.

Bill Dearborn

Why not go with 18x9.5 wheels all the way around? You must be running a very tight course if you are having trouble putting the power down coming out of a corner. Most road courses can be run in 3rd and 4th. The car can handle a square setup. Try 305 tires on the 18s. The big issue is getting more front tire not less rear tire.

Bill

gmccreary

I'll be running 275/40-17 Hoosier R6s on all 4 corners this weekend at Roebling Road. I'll let you know how it goes.

sothpaw2

Yes I have used the 9.5 at all 4 and it is an acceptable economy setup for the beginner. I used 2 new supercars front and 2 Nitto R-II rear to get more rear grip. I don't recall any active handling issues. The Corvette is in general a "slower in, fast out" late apex car. You need the rear to be able to lay down the power it has soon as you can. This is just fundamentally different from a Miata or even Caymen S; they don't have that kind of power to put down it's not so critical to get rear traction and I doubt they have to baby the throttle to avoid oversteer.

Along these lines, if it was streetable and looked ok, my next mod would be a big rear wing to get some downforce on the rear tires. Powerwise, my car only has headers so the while other might cam it or otherwise add some power, all I'd like to have is more rear grip to apply what I have sooner.

brkntrxn

I run 17x9.5s with R6s as my practice and qualifying tires and they work just fine. I even set the TTA lap record at Charlotte Motor Speedway on 17" R6s if that gives you any idea.

bags142

I am running 4 17x9.5/275 17 z06 wheels on my frc for HPDE weekends on NT-05's.

I am still new to this, but I decided to go this way to save $$$. I have had no issues. I even drive it to events like this with no issues.

I thought about bumping up to 18's square...but, like you said, for $750ish for all 4 moutned and out the door, I like it and I am sticking with them!!!

Only thing I would suggest is looking at Nitto R-II tires. A few folks seem to think they are better than the nt-05. I have no 1st hand knowledge of this.

Allthrottleandsomebottle

You can have a lot of fun running a 18 x 9.5 square as I wanted to save $$$ as well.
OEM mag wheels work great.

I have done it on my 97' at VIR sucessfully



No issues with TC or anything else.




Also ran this set-up at CMP & VIR on the 00'........no issues as well