Forgive me if I'm beating a dead horse. I've searched all over this fourm and can't seem to find the answer.

I want to buy a set of wheels for my c6 coupe that will fit track tires.


Here is what I've learned so far:
- Factory front wheels should be 18x8.5 with +56 offset.
- Factory rear wheels should be 19x10 with +79 offset.
- Z06 and ZR-1 wheels will not fit on my c6 coupe due to fender limitations.
- Best track tire availability seems to be tires that fit on 18x10 wheels.
- As usual, lighter and stronger wheels are preferred where available.

With that in mind, here are my constraints:
1) Rim size should be 18" front and back.
2) Rim depth should be as close to 10" as possible on front and back.
3) Tires must fit on the vehicle without extending past fenders or rubbing during a turn. This means getting offsets and rim depths correct.
4) I'm not opposed to buying custom wheels, but I will look into cheaper options first.

What I'm asking: Please help me find wheel and tire dimensions that will fit on a c6 coupe and fit commonly available track tires.

 

I went with C5Z rears all around. Good prices, and light weight.

 

Thank you. Those wheels look like a pretty good fit as far as finding track tires for them.

I do have one more concern though, and that is that with reduced offset and increased width, they look like they'll stick out of the fenders quite a bit. I don't mind doing a wide body kit to make them fit, but that brings up new concerns about changing the scrub radius.

So the next question is this: What is the scrub radius front and rear on a narrowbody c6, and what effects will adding wider wheels (and increasing track width) have on the suspension geometry?

 

They did not work for me. The offset had the tires sticking out. I have a set if you want to fit them, but your profile is missing important data, like your location.

 

Our GT2 wheels clear C6Z brakes and tuck under the stock C6 fenders if you wanted to do something like that but they are a different size than what you are looking for. 18x9 front and 19x10.5 rear. I believe both Hoosier and Pirelli make a competition tire for them. I know we ran a Pirelli slick on our car with those wheels without issue.

If you are looking for 18 front and rear it is pretty much either the C5Z wheels or look at something like a Finspeed or Forgeline.

Anthony

 

That sounds awfully close to the factory c6 coupe wheel sizes, so I'm not surprised that they'll fit. If Pirelli and Hoosier make tires that fit those, I may be able to stick with what I have. I'll look into their tire lineups just in case.

Regardless, where can I pick up a set of those GT2 rims?

 

We went a bit wider on the cars and run a 265 or 275 at the front and a 305 at the back so it is a little more balanced tire wise.

Any one of our vendors have them or you can buy direct.

https://www.lgmotorsports.com/lgm-c6-gt-2-wheel.html

Can order either online or via phone with myself or Cesar.

 

Anyone run c5 rears on on the c6? Not too far off. I'm thinking about test fitting c5 rears to mine.

C5 (coupe/vert):
Front 17x8.5", 58mm offset = 7.03" backspace
Rear 18x9.5" 65mm offset = 7.81" backspace

C6 (coupe/vert):
Front 18x8.5", 56mm offset = 6.95" backspace
Rear 19x10", 79mm offset = 8.61" backspace

 

Look at my picture above.

 

The z cars have a different offset 10.5" at +58 . A c5 wheel should sit in 20mm from where your c5z wheel sits. Not perfect but maybe good enough for me.

This is according to 1010wheels offset calculator.

 

Back when I used to do HPDE events in my c6 with standard fenders, I bought a set of 1997-1999 c5 "wagon wheels", which are super strong, not the lightest weight, but I was not racing competitively. I used Nitto 555R2 275-40-17 and 305-35-18 tires. They had amazing cornering capability, like 10x stock, and they had enough tread that I could drive them to and from the track even in the rain.

Zero issues with active handling or "drag control", which you will get if you don't maintain close to stock stagger in height between front and rear tires.

I did have to put on standard, non Z51 front brakes, which are the same as C5 brakes (swap the brake caliper mount and the rotors) which I wanted to do anyway as the c5 front rotors are dirt cheap, used to be like $20 each and of course you will end up cracking your rotors on the road course with track pads.

It was a very inexpensive setup and worked very well for me. Just an idea for you.

Edit, seems Nitto doesn't make the 555R2's any more, but the NT01 is also a 100 tread wear tire which is what the 555R2's were.

BTW the autocross & road race section in this forum has a TON of great info and support, check it out as well.