fennerhillpro

Just got done my 4th Track day at Watkins Glen an got signed off to drive solo. So here is the issue. I have a 2007 C6 with F45 SUSPENSION everyone is saying I am really driving well and my lines are good and smooth. I added 305/30/19 and 265/35/18 tires on Nurburgring wheel which are .5 wider. Everything fits and works well.

Issue noticed the rear wheels sidewall is tearing up a porsche guys says the fenders are hitting they just roll the fender. Seems corvette with plastic can"t do it. I could upgrade suspension but afraid to add stiff rollbars and shocks. Advice?

gkmccready

Get wheels that fit. :-) Try to figure out where the tire is hitting the fender. There's a black inner fender piece you can trim a little, but if it's hitting the painted fender itself your best bet is just getting rims with the correct backspacing.

fennerhillpro

They are hitting on the inside of the painted fender.

John Shiels

then you need to cut them or as stated get tires that fit. Is the car at stock ride height? Is it hitting the edges or the inner part of the fender? How much clearance do you have? Adding stiffer suspension could help but as you get faster it may happen again.

fennerhillpro

It is stock height the only mods are oil cooler, radiator, dual fan and brakes. It is just bearly rubbing on the inside of the fender lip I will bring it to a body guy and see if he can shave it down a bit.

Here is the suspension issue the car seems perfect balanced right now witht he large wheel and in sport mode. A few non corvette guys said I could go with stiffer springs and like a Hotckins swaybar to stiffen up the front and back. Other guys said if I do they be careful as the back my start geting jumpy. What do the c6 guys say?

RDnomorecobra

you say they are .5 inches wider but is the offset correct? which side did the extra .5 inches go to? seems at least some is on the outside. maybe a little too much.

gkmccready

So, you can running narrower tires, add more negative camber, or get wheels built for a C6 (ie. correct backspacing/offset).

If I had a brand new C6 to start from again, I would make the changes in the following order until I was happy:

• Lower the car to around 4.5" to the front jacking puck hole
• 3/8" rake (ie. 4.875" to the rear jacking puck hole)
• -1.75deg front camber, 7deg caster, 1/32" toe-in
• -1.25deg rear camber, 1/16" toe-in (1/8" toe-in if no poly bushings)
• Cornerweight with full gas tank (51% front, 50% cross, 50% side-to-side)
• Wheels & Tires (CCW, Forgeline, C5Z rears, ...)
• GM T1 or LGM G1 or Pfadt swaybars
• Springs & shocks (two choices)
  • VBP Extreme Leaf Springs & Revalved Bilstein Sport Shocks
  • DRM Bilstein Coilovers
• Poly bushings (VBP or Pfadt)
• DRM SS Caliper Pistons
• SS Brake Lines
• DRM Brake Ducts
• Base model caliper brackets to use C5/base rotors (NAPA or 2pc)
• DRM/Ron Davis Radiator

ptindall

/thread

fennerhillpro

Interesting thing I purchased these from WCC and they told me they would fit no issues. I put factory size tires on and they looked like mushrooms so I read on the forum and got these all was good prior to learning how to drive. Here are the wheel sizes guess, I will have to make an adjustment
•Front - 18x9.0 Nurburgring +50
•Rear - 19x10.5 Nurburgring +65

I found this for factory or stock C6 -

Front wheel size: 18x8.5 offset: +56 mm

Rear Wheel size: 19x10 offset: +79 mm

dbratten

Wheels are a close fit with those offsets. I run the same front spacing as you on my race wheels but the diameter of my tires is close to 1" shorter.

As suggested, you may add more camber (I run -1.4 rear) which will tuck in the top of the tire and keep it from rolling to the outside. Also, looking at your avatar your car seems a little low in back for the recommended rake. Lifting the rear a 1/4 - 1/2" may also solve your rubbing issues. In time, the tires will self-clearance on any plastic.

fennerhillpro

Great news what camber do you fun in the front? I might as well have them change it all when I goto the alignment place

dbratten

I run -2.2 in the front along with -1.4 on the rear. Both settings are run on the street as well. I run close to zero toe F&R on the street. For track use I add 1/8" toe in on the front and 1/8" toe in on the rear. For autox, I change to 1/8" toe out in front. The rear remains at 1/8" toe in. For racing I run big Kumho 710s. I do my own alignments.