cleanerPA

Can anyone with experience with this issue please help?

I've been going round and round with several wheel companies trying to figure out exactly what spec I need to order to make this work:

I want the maximum size tires that will fit front and rear without sticking out on a regular C6, NOT a Z06.

I've been told 18x10 front, 18x11 or 18x12 rear.

Problem is, I need to know the exact offsets needed so I can order wheels correctly. Also, it would help if someone could tell me what clearances are necessary for Z06 brakes as I want the clearance if I do upgrade the brakes later on.

The reality is that Fikse and CCW have the info and can order me the correctly-sized wheels without a problem. I can't afford the Fikses and I would like at least one other option besides CCW.

If someone has the exact specs- offsets front and rear, backspacing, caliper clearances, etc., at this point I'm almost ready to pay someone a consulting fee to get this right.

Thanks

Silverton

Talk to John at CCW. I believe they use standard C6 offsets for 18x10 (and 18x11) front; and 18x11, 18x11.5 rear. I'd like to know if 18x12's will fit in the rear! I have 18x11 fronts with 295/30-18 PS2's on my C6 Z51, but these tires are too wide unless (from what I've read) you run at least -2.0 deg. camber!

Webz

http://forums.corvetteforum.com/show....php?t=1096506

gkmccready

That would be me. I need at least -2deg camber up front with 18x11s and 295mm R888s to not have the top of the wheel stick out "too far". The 18x11 fits great in the rear and I'm certain an 18x11.5 would fit even better... I'm not sure about an 18x12 or if it'll be real tight without a lot of negative camber back there.

For the street I think an 18x10+18x11.5 combo would be ideal. For the track I bet you can get away with 18x11+18x12 with enough camber, but you really should ask John@CCW for your best fitment.

cleanerPA

How does this really help when I'm asking about offsets for non-standard sizes of wheels?

I'm not asking "what is offset?" I'm asking what offset I need for a specific application. Thanks.

cleanerPA

I can see that John would be helpful if I were ordering CCW wheels, but I need this info because I want the possibility of ordering wheels from someone other than CCW. Thanks.

gkmccready

You could just measure it. There're a few wheel manufacturers that'll describe how to measure backspacing and offset...

cleanerPA

I can measure the backspacing and offset of my stock C6 wheels, yes.

How would I measure caliper clearances for Z06 brakes on a different wheel when I have neither the caliper or the wheel?

Does anyone have published specs for the Z06 rotors and calipers- offset of the rotors from the mounting face, thickness of the caliper body in relation to the mounting face, radial clearance required to the inner rim of the wheels, etc.?

Or is this really an issue of if the manufacturer doesn't want to help out, I'm stuck with trial-and-error and a possible multi thousand dollar mistake?

gkmccready

Honestly, this is why I ended up with CCWs. They know Corvettes. They know what fits and what doesn't.

If you ask in C6 Tech or the Wheels & Tires area you might find more information. Especially about clearing the C6Z brakes... I'd be surprised if they didn't clear the stock wheels.

My car isn't near me today, and you don't want my info, anyway. The 18x11 front wheels won't work unless you're going with an aggressive track alignment.

gkmccready

PS- You can measure hub face to fender, and hub face back towards the wheel house to get your backspacing and offset without needing a wheel to measure from... you could also measure your stock wheels and based your numbers off how much clearance you have each direction. Any wheel company worth working with should be able to work from those measurements. And any wheel company you would want to work with has probably already measured on the vehicle you care about. :-)

Correction: When I say "hub face" I mean the mating surface between the rotor hat and the wheel. Otherwise you'll need to tell them the thickness of the rotor in this area to get things right.

Wayne O

As was mentioned, I also would suggest you talk to John at CCW. He's a true wheel expert.

For the street I use CCW SP16A wheels, 9.5” x 18” front - 11” x 19” rear with Goodyear Eagle F1 Supercar EMT’s...275/35ZR18 front - 325/30ZR19 rear...stock Z06 tires. The fronts have a backspacing at 7.75" which is 64mm offset. The rears have 9.15" backspacing which is 79-80mm offset.

For the track I use CCW C10 wheels 11” x 18” all around with Kumho 710 tires...305/30/ZR18 front – 315/35/ZR18 rear. I use hub extender on the front wheels (-1 degree negative camber).

I'm no expert. I'd rely on what John says.

Silverton

I'm not familiar with the term "hub extender." Could you elaborate, please?

Also, do you have a wide-body Z06 kit?