waktasz

Hi everyone,

This is probably rehashing some old info, but I can't seem to find the answer to these questions anywhere so here goes.

I'm looking into getting a c5 z06 to use for autocross duty. I'm not new to autocross, just to Corvettes so I'm wondering what setup you guys are using as far as wheels and tires.

What is the stock wheel size, offset and bolt pattern? What is the tire size of choice for the most part? 275/315 f/r?

Also, lowering the car on stock bolts seems like it would be legal in stock class, since you are using stock hardware. Am I right? Are there any downsides to doing so?



Here's some pics of my old and current autox cars for fun

acrace

Stock sizes are 17" x 9.5" front and 18" x 10.5" rear. Not sure about the bolt pattern and backspace.

Both 275/315 and 295/315 combinations have been successful at the top levels.

Stock bolts can be used for both corner balancing and lowering. Be careful about lowering too much. There is always debate about the negative effects of excessive lowering.

Have fun!

waktasz

Great! Thanks for the info.

Believe it or not, a set of autocross rubber costs more for my Subaru than it will for the Vette. Those 17s in front are much cheaper than running 285/30-18s all around.

Z06Fix

I will be running 295/35/17 fronts and 315/35/17 rears next year. Hoosier A6's. These will be mounted on 17x10 and 17x11 CCW classics. I'm setting the car up for ASP.

waktasz

I guess I should have mentioned I'll be keeping the car in SS. That sounds like a bad *** setup though.

waktasz

One other thing...what do you guys use for numbers? I guess my magnets aren't going to work.

acrace

Some people use static cling or low tack adhesive numbers. I don't have the discipline or patience to use either product, so what I do is cut out a bunch of numbers and letters at the beginning of the season using contact/shelf paper.

For the events where you need to put sponsor decals or sanctioning body decals on the car, I just put them on and then peel them off afterwards. Again, some put those decals on the static cling, but (at least the static cling I used) the static cling can shrink with sun exposure.

Bill Dearborn

I use the old standby: White Shoe Polish on the windshield.

Bill

TedDBere

Good, I was getting lonely. When are you getting the car?

waktasz

I'm working with someone in Tampa that wants to buy my car. Once that is gone I will make a move on something.

I will miss the local AS competition in our region though.

waktasz

Here's another question...what are you guys using for wheels? I see CCW is popular but I'm not in the mood to spend $2500+ on wheels (again).

TedDBere

If you don't want the expensive aftermarket wheels just stick with the stock wheels. They're pretty light and many of the top Z06 drivers in the country run with them. FWIW.

acrace

Agreed. In actuality, you wouldn't believe just how stock many of the top SS cars are.

EvilBoffin

The OEM wheels are either made by Speedline or Alcoa, so they're pretty darn nice & light themselves.

You can easily get a nice set of used OEM Z06 wheels either here in the C5 Parts For Sale & Tires/Wheels forums or brand-new from HouseOfWheelsOnline.com for very reasonable money ($880 or less, complete). The reason the top dogs in SS run the OEM's is cause aftermarket wheels in stock sizes really won't save enough weight to justify the big difference in cost.

rhneff

For the 17 x 9.5 front wheels, offset is 54mm which should give a backspacing of 6.9".
For the 18 x 10.5 rears, offset is 58mm which should give a backspacing of 6.4".
Hole pattern for all C5 wheels is 5 x 120.65mm (4.75").

For what it's worth, there is little weight advantage with the CCW wheels - in the same size/offset they're within a few ounces of the stock Z06 wheels at least as I've weighed them. That said, the CCW's do concentrate the weight closer to the center of the wheel so there is some rotational advantage but only an alien like Junior Johnson could tell the difference. The main advantage of the CCW's is two-fold: one, they're three-piece wheels and thus re-buildable if you manage to bend something (I have), and two, they can be custom ordered with specific size/backspacing so for example you could add the 1/4" Stock allowance to the fronts and subtract it from the rears - if you wanted to .

waktasz

Great info. Thanks guys.

Last question (for now)

What are you guys running as far as front swaybars? I know in Subaru land we generally run the biggest front sway we can find to try and keep the front of the car flat and the tires on the ground.

sperkins

I'm running the Nitto 555R2 Extreme road race tire. 275f and 305r. I've only done one autocross event, but was able to pretty much spank everybody with these tires and a completely stock '03Z. I found the best price through forum sponsor TomZwheels. I also run these tires on road courses, but I'll swap to slicks as I get more experience.

CamaroAJ

i run the T1 sway bar because i work for a chevy dealer and its uber cheep

also Speedline are lighter than the Alcon and stronger as well. 02-04 have the speedline.

acrace

Top cars (SCCA wise) seem to be split between the stock bar and the 32 mm Addco bar. What bar you run up front will affect your rear toe settings.

You don't need a big bar up front to keep the front of the car flat, as you can dial in lots of negative camber into the car.

Speedline ('02 to '04 OEM wheels, as Camaro AJ points out) are 0.4 pounds lighter per wheel than the Alcoa. Speedline name is cast into an oval recess on the backside.

rhneff

As acrace indicated, there's no absolute right answer regarding the front bar and it depends as much on driving style as anything. I ran the same 32mm hollow ADDCO (from Sam Strano) bar that Pat Salerno had on his Z06 before he went over to the dark side - learn from the best, I always say. The only caution is not to go too stiff or the car will get pushy - and a T1 bar is way too stiff (for autocross) plus its quite heavy compared to the ADDCO bar.

Don't know if it's still there, but Grassroots used to have a good tutorial on sway bars: www.grmotorsports.com/antirollbars.html .