Shzfast

Hello all, I hope you had a great weekend. I have a question that is more of a curiosity thing than anything else, before I do my coilover install. I tried to find a previous thread but not much luck that specific to my situation. The wife and I were out this weekend and had the opportunity to play with a BMW M5 and I noticed I had some very minor rubbing on the left rear tire while running through the curves. I could smell it but after I got home, I couldn't see any evidence of rubbing and thank goodness the fender liners were still intact. I live in Chattanooga, TN and we have a lot of twisties and mountain roads and this is all the car ever sees, I do not track the car. My question is, is it a possibility that the leaf spring can be weaker on one side (even though it is one piece) and/or the shock not control the rebound of the car? My car is a 2007 Z06 with 47,000 miles along with the ZR1 setup with a set of Cray Falcon wheels and a set of Continental Extreme Contact tires. I weigh 198lbs and the wife weighs less than I do and the car had half a tank of fuel. The car is very mildly lowered on stock bolts and is level side to side (pic below). Initially, I thought it was the ZR1 setup, but with the Cray's and the Continental's have almost the same overall dimensions compared to the stock setup with very minor differences according to Discount Tire's tire calculator. I am planning on a set of Pfadt coilovers just to have true independent 4-wheel suspension and hopefully a better controlling car and will hopefully help prevent crosstalk from side to side. Thank you for your feedback.

StayinStock

I guess my first question would be what tire/tire size are you running? With the wheel gap in that picture I highly doubt its a height problem as much as it is a size issue. Its possible you could have a spring issue but I doubt it, you'd feel it in the way the car handles.

El_Steveo

I'd check for sidewall markings on the inside, the tire may be flexing enough to hit the inside area around the suspension. Of course I say this if you're running a larger than stock size.

Shzfast

The tire size is the ZR1 setup so it’s 335/25/20 in rear and 285/30/19 in front. The Crays are 19x10 and 20x12.5. I can’t recall the offset but it has been modified by Cray to account for the extra width. I don’t see any obvious sidewall markings but I did not think about the inside. Good idea guys. I will get the wheels off and take a look this week when I have it up for a diff fluid change and oil change. Let you know what I found. Hopefully 🤞 no rub marks lol 😆

6 Shooter

Maybe I missed it, but does your Z06 have Magnetic Selective Ride Control?

Shzfast

6 Shooter it does not have magnetic ride control. Driving around normally, the car appears to drive just fine. There is no excessive bounce or skipping of the rear end when going over bumps. I was just curious if the mono leaf could get weak laterally right or left or even possibly both. The only evidence I have that it rubbed was the fact that I could smell it. There aren't any marks on the tires or the inner liner and I know it wasn't the car I was messing with because I was ahead of him.

6 Shooter

I don’t have a Z06 but I know my GS with Magnetic Selective Ride Control will touch it’s front chin from time to time in the Ozark twisty’s if I’m not in Sport mode.

KBu

I have the same issue with my GS.Same size wheels and tires.I was told by someone more knowledgeable than my self that the rear cradle on some C6 come from the factory up to (I believe)6mm out of line and there is no way to correct it.Signature wheel (which I have) advised that I could have 4mm machined off of the mounting service of the wheel.I never did anything and just drove the car.Fender would barely rub the sidewall under certain conditions.

Shzfast

Thank you for the replies guys. 6 shooter, that is wild that your car hits in the twisties unless you are in sport mode, thank God for sticky rubber. Like any good Corvette driver, hit those corners like a mad man lol KBu, I also thought about shaving the mounting face of the wheel but couldn't find anyone I trusted. Also, I figured that Cray and other great wheel manufacturers know what they are doing and surely they did their homework, unless we both got wheels that were made on Monday or Friday That is interesting that you talk about the cradle being off center. Shoot most men complain about 6 inches, I just want 4-6mm. I had one guy tell me to grind down the inner quarter panel a bit and I said "Do I look like a butcher, I'm not about to slice up my girl". I am okay the way it is I guess because it only happens if I am shooting it hard in the turns so I guess I will have to put a block of wood under the gas peddle lol. Thanks for the input guys, I am hoping that the Pfadt coilovers dont make things worse. I am hoping to have them on next month or August. Let you know what happens.

Shzfast

Well I couldn't wait, so I took the tires off and El Steveo, no rub marks of any kind that my 51 year old eyes can see on the suspension components. The fender liners show no shiny spots and the tires look great. I did notice a bit of black smudge on the inside quarter panel lip. But like StayinStock said, I am surprised at this given the wheel gap I have. I raised it a bit when it had the Michelin's on it because it would rub the outer edge, but it was much lower and the Michelin's are more squared off. But now that I look at my pic, it looks like GM made a 4x4 Corvette all I need now is a mullet and an open beer in the cup holder I am going to be conservative with the Pfadt's and slowly lower it and drive to let it settle, rinse and repeat, until I reach that sweet spot. Is the cradle being off kilter an entire generational C6 problem??

Lee Cromwell

Could you have possibly been smelling something different besides rubber from the wheels? Were you driving really aggressive? Clutch smell? Brakes etc?? I know we can totally tell the difference between rubber, brakes, clutch smells but...
When I'm driving my SL600 with the top down I'm constantly smelling stuff and it freaks me out but it's just random crap that normally can't smell with the convertible top up .

Shzfast

Lee I was deinitely driving aggressively, but there was no brake or clutch smell. The curves we were rolling through were long wide sweepers, so not a lot of shifting or need for braking. It was definitely tire smell without a doubt. I did notice some black smudge stuff on the left hand quarter panel inner lip and there wasn't any that I noticed on the right hand side. So I am leaning towards what KBu said about the rear cradle being off by just millimeters. The quarter panel mustv'e just ever so slightly shaved the tire without leaving any noticeable marks. I am thankful it didn't get the rim as well or blow out the tire since the Continental's are not run flats lol. And StayinStock had a good point about the tire/wheel size. The ZR1 setup definitely fills out the wheel wells more so than the factory Z06 wheels/tires do, but if I put my factory wheels back on the car, suddenly she turns into an ugly duckling lol.

Dano523

Suspect on the corner balance being correct to begin with, since rear tire gap to fender is looking like front gap to fender as well.

ZR1 does use larger rims for the larger front rotors, but the tire sizes are one profile smaller than the z06 set up, to keep the ods of the tires about the same between the two.

As for C6 fenders, bolted to the frame, and lets just say that the distance from side to side off the frame, is not always the same for both sides. So if rim off sets are not correct, then could have one tire slightly past where it needs to be inside the tire wheel to prevent the rubbing.


Last one, and the lower you have the car, the less suspension travel you have, and the weaker that your making the springs as well.

ki-speed

Put some blue painters tape on your fender liners and go for a spirited drive. Then look for any rubbing on the tape.