gkmccready

CCW C140 18x11 with Toyo R888 295/30 on the front of a C6 non-Z with approximately -2deg camber. I had the shocks and springs off the car so I took the opportunity to check the clearance.



As you can see, with the wheel straight ahead things are *VERY* close. With a 1/4 turn to the left, things start to get ugly:




Note to self, for big bumps that cause full compression, make sure the wheel is absolutely straight. I have no idea how folks are running with 315s and the wheels sticking out on the front unless they're really limiting travel. The tire rub you can see was from running -1.2deg camber and just shaving the tire with the fender lip.

AU N EGL

need more neg camber

Did you lower your car and by how much?

Remember sidewalls flex on high speed corners so those fenders might be toast very quickly.

gkmccready

More negative and it'll hit the wheelhouse on the inside just as quickly as it'll hit the fender on the outside. And remember I had the shocks and springs off to check clearances. Ride height is pretty close to as delivered at ~5in to the jacking puck holes.

If others are running 315s on C5Z rear wheels and not smashing up their fenders, and likely running much lower trim heights, we must rarely get to full bump travel in these cars...

gkmccready

Follow up... I had gone from 18x11+295/30 to an 18x10+275/35 wheel -- and I was still rubbing on the fender a bit. The front wheels were still sticking out on me.

Today I went back to using the stock eccentric bolts for alignment and removed all the spacers from behind the front upper a-arms. This sucked the top of the wheel in about 3/8" and now with the 18x10 and 275/35r18 tires everything looks great. I'd still be a bit nervous about the balance between hitting the fender and hitting the wheelhouse. I think an 18x10.5 would be pretty close to perfect here.

Overall the car feels better, too. I lost at least 3/8" track width sucking the wheels back under the fenders this way, but I have to say everything felt great on the ride home and I'm looking forward to getting out on track with a car that won't have the tires hitting the fenders for the first time in a couple years...

I'm finally coming around to seeing how the C6 guys run the C5Z rears on all four corners successfully! Many thanks to Randy@DRM and RAFTRACER for talking some of this through with me. Very much appreciated!