kpctoy

Ok,

Looking for advice/feedback. 04 Z06 split between 4-6 track days, 15+ autocross and my ride of choice to work 1-2 days a week. Plan to make the jump to Gary's BBK in the coming weeks and I'm faced with a track/street/autocross wheel dilemma.

In order for me to keep 3 separate sets of wheels I'm going to need to go to 18"s for my street setup. 18x10.5 square to be exact. I need to buy 2 new front tires in the 18" size so should I run the same 295/35/18 all around for the street? Any issues with rub or clearance?

Pro's/Con's feedback or experience welcome.

Thanks,
Kevin

froggy47

It seems popular with a few guys, but I have always wondered about the ride height & rake.

The 18 rears are taller than the 17 fronts in most cases that I am aware of, so you put 18's on the front you raise it up. Then what you raise the rear up more?

I'm not sure I want the CG of the car that high.

Anyone else?

bobmoore2

Don't forget that your computer wants the fronts' diameter/circumference smaller than the rears'. Otherwise your AH and TC will not work right. No AH/TC is a good thing on the track, but I would be afraid to drive a Corvette on the street without AH and TC, because I know my alertness level isn't always good on the streets.

If I had a C5Z06 with 18 x 10.5 wheels all around, I would run 295/35-18 in front and 315/35-18 in back, or maybe 285/35-18 in front and 305/35-18 in back. I know you can fit anything between 285 and 315 onto a 10.5 wheel, because I've done it.

argonaut

Not sure if you know this but Gary's BBK (AP Racing 8350) with the 12.8" rotors fits just fine under the 17x9.5 Z06 OEM rims. They will also fit under other rims, like the 17x8.5 thin spoke if you use spacers and longer studs.

kpctoy

This is good feedback so far...

bobmoore2-+1 sizing and throwing off the factory "nannies" is news to me. Do you have a place I can research that info from?

argonaut- yes, I have to rotate my wheels because my CCW Classics won't fit. I currently run classics for autocross, knockoffs for track and stock wheels on the street. I plan to use the streets now as my autocross wheels leaving me with a need for a street setup that looks good and clears the BBK.

My plan is to go 18x10.5 TSW Nurburgring wheels all around and will only need to buy 2 new front tires.

fej

I think for street use I would run the 285/35 and 305 or 315 rear. I would want to maintain the stock rake and AH/TC as well. And I have been 315/30/18 square, 305/18 front 335/17 rear etc on the autocross course. Right now I am 295/18 square on factory 10.5's.

For street use you could probably go to a 275/35 front and 295/35 rear and be close to factory sizes, but its early and I am too lazy to do math heh

G'luck
Fej

RDnomorecobra

search on this ... some say they have problems with nannies, some dont. I for one have not. I run 295/35 on the street and 305/35 or 315/30 on track. I run square so I can rotate tires. more economical. full steering wheel lock with 315's will rub, especially with brake ducts.

front end of the car hunts in grooves a bit more on the street than with the narrower 17's. not too bad though. should have two hands on the wheel anyway. price to pay I guess. as far as ride height and rake, I live near Joe @ Pheonix so he sets my car up. maybe worth a call to him to discuss, I'm not expert enough. bottom line car handles great on the track with these wheels and Joe's setup. i think there's some pics of 4x18 on here as well so you can see the front wheel offset and how the car sits from a side view.

kpctoy

Anyone else?

mph1972

On my coupe, I ran 18x10.5 on the rear with a 295-35-18 and a 18x9.5 on the front and had no issues. I am dealing with this also. I really want to do this also, but going wider on the front than I ran in the past.

Not sure if the narrower wheel on the front was why I never saw the AH or TC codes thrown.

AU N EGL

Only thing I noticed about my wide tire square set up, is driving slowly in the paddock or on the street, the car feels like a pig in the mud.

driving Slowly in parking lots, around a corner at an intersection.

and as far as the AHTC codes just turn them off.

Wicked Weasel

Personally I dislike anything larger than 285 on the front for the street. Anything larger follows the groves in the pavement and is annoying to me.

AU N EGL

I agree for street use 285 up front is about max.

JiminVirginia

On the street and for HPDE, I run 285s up front and 305s in the back using identical OEM sized 18s, as you describe. No problems with the nannies. I can turn everything off and no issues. Works fine.

You can always adjust ride height using the stock bolts. I find I don't have to fiddle much. My car is not totally lowered.

Jim

kpctoy

I opted for 18x9 up front and 18x10.5 rear. Going to run a 265/35 up front and 315/30 out back. Then again with all this snow I may never get the car out of the garage!

Thanks for the feedback everyone!