trapp

I have a 09 C6 Z51. I want to run R compound but I have 19's in the back and to date I don't know of any R compounds that come for 19' wheels. I want 18' wheel front and back. What size do I need???

trapp

bobmoore2

I've got a 2006 C6 Z51 that I take to the track about once a month.

I am using CCW wheels and Kumho V710 tires, and I'm very happy with the lap times I'm getting.

Front wheel: 18 x 10 with 56mm offset (I've been told that an 18 x 11 will fit also.)
Front tire: 305/30-18

Rear wheel: 18 x 12 with 79mm offset
Rear tire: 315/35-18

These are about the biggest wheels and tires you would want to put onto a C6. (A Z06 or GS can accept bigger.) There is no interference with anything inside the fenderwells, and they only extend a tiny bit outside the fender wells.

The grip is very good, and a huge improvement over street tires. The car is well balanced, too. It has a slight tendency to understeer that is easy to change to slight, controllable oversteer with a little added throttle.

There are several tires options for the C6 - Toyo R888, Nitto RII, Bridgestone R1 (limited sizes), Kumho V700, Kumho V710, Yokohama (a couple models in limited sizes), Hoosier R6, Hoosier A6, and a few more I can't think of right now.

If you're just starting on R-Comps, it might be a good idea to start with the Toyo R888, Nitto RII or Kumho V700, because their performance near break-away is a little more forgiving, less sudden. If you have prior experience with R-Comps, then I would recommend the Kumho V710 or the Hoosier A6. Occasionally we can find a good deal on some of the full-slick race tires made by Hoosier, Pirelli, Goodyear, etc.

I can give you the names and contact info for a couple people who sell scrubs (lightly used tires), if you want. I highly recommend buying scrubs, because the tires have 60 to 80 % of their life remaining at less than 1/3 the price. Email me - bobmoore55 at yahoo dot com

trapp

Thanks for the info... how many track outings should I expect from say a Nitto RII or Toyo R888 or Kumho V700. Did one product seem more durable then the next?

rustyguns

I have same set up on the C5

gkmccready

I have 18x10+18x11 CCWs with 275/35r18+305/35r18 Toyo R888s on my C6 Z51. I had 18x11+18x11 CCWs with 295/30r18+305/35r18 R888s... with camber plates that pushed the track out wide I was having clearance issues and hitting the fender with the tire. I went back to the stock eccentrics after I noticed even the 275mm on 10in wheel looked really close to hitting. With no spacers between the front uppers I rub on the inner wheelhouse with the 18x10 275mm set up as I approach full lock.

Bob, I'm really surprised you can clear 305+315 on both the inside and the fenders!

rustyguns

for me it depends on the tire. 888's do run wide and they hit a little

trapp

So both recommendations cause rubbing issues at full lock....hum what is the recommended sizes that DON'T rub under track conditions.....

rustyguns

i never drive full lock on the track, so i don't care

anyone that does is spinning lol

trapp

I thought you meant full lock in a corner...were the suspension is at its max lateral tilt....not locking up the brakes. I just don't want to rip a side well out going through the corners.......

Git Er Dun

I know a popular setup now is 18X11 front and 18X12 rears. A lot of people are switching to 18X13 rears also.

I have a C5 with 2" wider rear fenders. I run a 18X11 front with a 315 and a 18X13 rear with a 335. I run PS2 street tires but if I was going to run a DOT slick it would be a 345 on the rear. They don't make any street tires(anymore) in a 18 that are 345's.

VatorMan

I just bought a set of 18X11 and 18X13. On a GS what is the maximum rubber I can use without interference ?

SO far I've heard 315 front and 335 rear. My tire guy put 295 and 315 respectively and I checked clearance.

Front:



Rear:



You can see that the rear can accept larger meat on the tire. Plenty of clearance width and height.

rustyguns

like i said........anyone that turns there steering wheel to full lock position on a track is out of control

gkmccready

"Lock" means you've reached the steering stops... you'd better not get there on track or you're so deep in trouble you won't care about the rubbing...

AU N EGL

Full lock? how often are you going to turn full lock? Not.

Dont worry about it.

me

18x12 front 18x315/30
18x13 rear 18x335/30

Git Er Dun

Any large tire like a 315 will eventually rub. You don't need that much steering on a roadcourse though. Maybe in an autocross or when you are in tight parking lots but not for a roadcourse.

trapp

Thanks for the explaination.....I was confused on the term "full lock"...I NOW understand what you saying. I have airducts which may complicate things .......

bobmoore2

You will never turn to full-lock on the track, so rubbing issues at full-lock are not relevant.


I was a little surprised when I first tried them. I've been running that setup for 5 or 6 track days now and no rubbing. One day running Thunderhill backwards I got 6+ inches of air everytime I flew over the bypass, but still no rubbing when it landed. I've also driven The Corkscrew at Laguna Seca which really compresses the suspension.

"Your mileage may vary."

bobmoore2

My DRM brake ducts do have some rubbing marks on them, but nothing serious. When I feel the steering wheel hit the stops (in this case the tire is hitting the ducts), then I just back out of the steering a bit. The turning radius is still plenty tight for all the maneuvers I want to do in race track paddocks.

harrydirty

I'm planning to track my 2007 Z06 using Kumho V710's with 18x10 wheels front and 18x12 wheels rear. The V710's at Tire Rack limits me to 285/30R18 on the fronts, which make the overall diameter 24.8 inches vs the stock diameter of 25.7 inches. The rear diameters are pretty close to stock. Does this matter, will any of the car's electronic "watchdogs" complain? I plan to run TPMS sensors in my track wheels.

harrydirty

I keep reading about resetting the TPMS sensors at the track when switching between street and track wheels.......what exactly is happening and why do the sensors need resetting? What happens if I neglect to reset when I switch wheel/tire sets?