SteveC68

Like the title of this thread asks will a 315 fit under the rear of a C6 Z51?

Thanks,
Steve

naschmitz

Hoosier R6 315/30/18s fit on CCW 18x11 wheels on my 2006 C6 Base Coupe.

Grabbed_Crow_Mobe

Naschmitz - Are you running a 10" ccw up front? If so, what size tire? I'm running a 295 but want to put a 305. Curious as to your setup.

taken19

I've had a 315 Hoosier R6 on a stock C6 rim as well as a C5Z rim on the rear of my previous C6 Z51. Slight rubbing on the inside fender liner but nothing to worry about.

naschmitz

Yes. 295/30/18 s on the CCW 18x10. Have not tried the 305s up front. The club I ran time trials with had a fender rule and the 295s were barely legal.

SteveC68

Hey thank you for all the responses. Follow-up question: How much negative camber were you running in the rear? Right now I have 1 degree negative which is about as much as I can get. I have not lowered the rear though which may or may not give more negative the lower you go.

Thanks again,
Steve

naschmitz

I am running -1.4 deg in the rear. I don't think the rear fitment is sensitive to camber. Here's a pic of the car loaded heavily in a turn. 305s on the front might be a close call for my setup.

SteveC68

naschmitz,

Great picture! What size wheels are the rears? Also what offset?

Thanks,
Steve

JonJ

Absolutely. I'm running 315/30-18 Nitto NT01 at all four corners on CCW 18x11 wheels. Offsets are whatever John at CCW recommended. I'll have to look at my original order if you want to know the exact offsets.

No real rubbing issues except for the front fender when the suspension gets compressed at the bottom of a hill. Otherwise the car is fantastically balanced and a hoot to drive.

CONE RACER

I've been running 315 / 30 / 19 Hoosier's on the rear of my C6 narrow body with Z51 for years. Lowered on stock bolts and never a scrub from autocross or HPDE. 315 / 30 / 18 Hoosier's on front - never scrubs.

naschmitz

CCW Corsair C14s

Front: 18 x 10, +57 mm offset (7.75" backspacing)
Rear: 18 x 11, +83 mm offset (9.25" backspacing)

naschmitz

Are you guys running camber kits? The reason I ask is that camber kits increase track width by about an inch and I think that would be a problem for me that might not be for you guys.

Grabbed_Crow_Mobe

You have 11s up front? I didn't think John made anything over 10s for the front of a base C6s.

JonJ

Pfadt camber kit. Still no rubbing aside from the front fender lip under significant compression.

JonJ

I was skeptical as well but he convinced me to get 11's on the front and I've been quite pleased. Happily I'm able to run a square setup.

9.25" backspace rear, 8.25" backspace front, both 18x11

Grabbed_Crow_Mobe

That's great news. I'm thinking about trying to squeeze a 305/35 up front. About the same width as your 315/30s but .7" taller.

Do you run brake ducting up front?

JonJ

Yes. DRM brake ducts in the front.

SteveC68

If you don't me asking how low on the stock bolts? Do you know how many threads are still showing? I'm the second owner of this car and have not touched the ride height, but there are probably 4-5 threads showing on the bolt between the top of the pad and the bottom of the spring. Did you cut down the pad on the bolt?

Thanks,
Steve

CONE RACER

I am lowered on stock bolts using measurements to the frame rails (at the factory recommended points) to get the proper rake angle in the chassis. Did not cut the bolts or pads off. The max is on one side of the rear which has just less than a full thread showing. The other three corners have various additional amounts to get the frame height measurements equal. Overall, my car came down about 3/4 of an inch, but more importantly it sits "chassis level" and helped the feel of the left/right balance in corners. The 315's on the front fill up the fender and wheel well, but don't touch. Lots of room in the rear wheel well with 315's.

No camber plates. I've got -1.9 deg on the front, but can only get -1.4 deg on the rear. When we set up the alignment, I thought it might be a bit tail happy at those settings, but it really wasn't. I run 2 psi less on the rear tires than the front and it's pretty neutral on push/loose.

As well as a lower CG, the other benefit I got was a tick less body roll. Probably from a combination of the alignment plus the lowering.

SteveC68

I'm at -1.9 deg on the front and only -0.9 deg in the rear. I can't remember looking at the front to see how many threads are showing, but the rear has at least 4-5. I've read that you can rotate the dog bones in the bushing on the front uppers and get a little more negative, but I haven't tried/verified that yet. I bought a trim height measuring tool used off ebay, but my garage isn't level enough to get a good reading. Just from the looks though my car seems to sit high in the rear.