BTTBSS

Last season I ran 255/40/17 front and 315/30/18 RT615K+ on my 2001 C5ZO6. Many people suggest 315/30/18 square on stock wheels. So I put my 315 rears on the front in the garage to test the fit. At about 1.5 turn of the steering wheel the tire almost hits the fender liner. I have 1/8 inch or less of clearance between tire and plastic fender well. Is this enough clearance? I would like to run the larger front tires next season, but I don't want to rub holes in the fender liner or cause other interference problems. Are the guys running this set-up seeing the same tight fit in the front?

spdislife

Ran that setup this year, As long as you're careful in the paddock with how far you turn the steering you'll be fine. The setup does do a number on my DRM cooling ducts though, but it's worth it.

dmichaels

spdislife

No mods to the ducts and I can't think of any that could be applied. I just try to be conscientious as to how far I turn the wheel off track. The ducts are showing signs of wear and will have to be replaced at some point, but I like the setup too much.

MX621

wtb-z

The fitment should be fine, even though the clearance is really tight. Running the 315/30/18 Rival-S (which is a slightly bigger tire than the Falken) I think it did rub a little bit there, but only on very tight autocross courses, and not enough to really worry.

smitty2919

If for autocross, run 315's and remove the brake duct. I don't think the stock brake duct is doing much for cooling during autocross. Road race would be a different story.

Another option would be to add a small spacer if your stud length allows. I had rubbing issues on my 95 Camaro to where I needed to account for at least 3/4" static gap due to tire deflection in the REAR to the LCA. The front I suspect will experience more tire deflection under cornering.

BTTBSS

The Hankooks are a good buy and I am more comfortable with the idea of a smaller tire in front. I wonder if the 315's will put too much strain on the power steering. No overheating with the 255/40/17's.

Quickshift_C5

dclafleur

I ran the square 285 Hankook setup for 3 days this year and really liked them. I can't really compare them to something more aggressive or a larger square setup as I haven't run either on my C5Z but I was happy with the combination.

jesup16

Just curious, why the Falken FK615+'s? There are plenty "faster" tires at that treadwear (200). A 275/285 RE71R or RivalS is faster than a 315 615+ and you won't have to worry about fitment. Us "STU" autocross guys run 275/285 square all day long. No issues...

BTTBSS

I wanted a tire that maintained the stock stagger in diameter and could be used on the street and track without changing tires/wheels. I have used them before and they are a decent dual purpose tire, but I'm more comfortable with the car now and looking to get a better tire set-up for next season. Last event of the year the fronts were getting into the ABS under hard braking and I think that was due to the smaller front contact patch. On the off chance it was something else I bought new DBA rotors and re-built the front calipers. FWIW the old rotors were centrix high carbons with XP-10 pads.

Olitho

In Spec Corvette the spec tire is the Falken 615K+.

We run 315/30x18 on all four corners on rims up to 11". Some racers use four 10.5"x18" C5Z06 rear wheels on all four corners which is allowed.

heinee

This discussion is of interest to myself as well.

Should I expect issues putting 315/30-18 Rivals using C5Z rear wheels with PFADT coil overs and agressive negative camber for autocross? I recently bought an 02 C5Z that is track prepped, but it still is on the stock 17's up front. It does have a set of aftermarket brake ducts attaching to what appear to be the factory plastic ducts.

I am planning on fitting 18x10.5's on the front, but haven't decided on the tire size yet.

Thank you.

Mark

jesup16

I have full brake ducts and use the 18x10.5 z06 rear wheels for a square setup with no problems at all. I have not run anything wider than a 285 upfront though... the wheel seems to clearance fine.

I think you will be fine on track and for autocross... you may want to avoid full lock turning as I heard 315's can rub in those scenarios.

FWIW, id rather rub on the less expensive brake ducts than use a spacer and destroy a more expensive fender. Ride height maybe a consideration too if you push the front tire out too far with a spacer.

DK83

If this is any help to anyone....

I went from 275/40/17 Fronts to a 315/30/18(nt01) square setup on my '02 z06. I have zero fender rubbing issues with this set up. I do have DRM ducts in the front and it rubs if i turn the steering wheel more than 1 full turn. However, the drm ducts rubbed even when i had the 17's in front.

Soloontario

When it comes to tire rub, remember that the tire diameter is also important as the rubbing occurs with the wheel turned. Generally a short tire will rub less than a tall tire of the same diameter. Personally had minimal issues with 315 NT-01s on 18 x 10.5" rims but the tire is only 25.3" diameter.