I have a 99 C5, have allways kept the pressures at 30psi cold.
Since the fronts are prone to inner edge wear , I had them take out a little Neg. camber on the last alignment to sacrafice a tad of handeling in exchange for a little more even tire wear.

The rears have 18k miles on them and the center portion seems more worn than the edges. close to approaching the wear bars. I allways used 30psi, and since its my wifes car shes not spinning the tires (that I know of, ha ha)

Another issue I have is all four tires have have little chunks of rubber missing here and there. We dont have a rock driveway and dont drive on any dirt roads.
any ideas.
thanks

 

Not an expert but it sounds like your tires are beginning to fail. Hey, they are at least 7 years old (we're in the 06 model year now) and likely older than that. Most tires only have a useful shelf life of 10 years and high performance tires are normally 5 or 6 years. If I recall, I read this at TireRack.com. You might want to check that out.

You can probably pick up a set of stock GY runflats for a few hundred bucks inside the C5 Parts for Sale forum.

HTH.

Jeff

 

Sorry I should of mentioned
this is at least the second set of tires on this vehicle maybe the third (bought the car used with 30k)
the rears were brand new 18k miles ago
I recently bought a nearly new set of fronts.

 

Centers worn more than the edges are a strong indication that you're running too much air pressure in these tires. 30psi seems like a good pressure, but unless your gauge is off, it's too much for those tires. While the car manufacturer's recommended pressures are usually pretty close, they are not necessarily perfect for every vehicle. Weight of the vehicle, the tires themselves and of course alignment will all affect this.

If you are confident in your alignment, there are a couple of ways to determine the best tire pressure for normal use.

The first is to use a tire depth gauge and take at least three tread depth readings across the face of the tire, this is your baseline. (outside, center, inside) Now monitor and maintain the same pressure in the tires and repeat the depth readings every thousand miles or so. Within a few thousand miles you will either see a difference meaning you need to adjust the pressure, or no difference in which case your pressure is pretty good. It takes a while to validate a good pressure setting, but it will work. I have detected wear variations in as little as 1000 miles.

The second and easier way is to borrow (or buy) an infrared thermometer. Go for a drive with your wife and after 5-10 miles have her stop the car in as straight a line as you can, a parking lot maybe. Jump out and take temperature readings across the face of the tire(s). Even temps across the tread mean you're running a good tire pressure setting. If they're warmer on the outsides, you need to add a couple of pounds. (Warmer in the center means you need to lower the pressure.) Do this a couple of times until the temps stay pretty constant across the tread. At that point you have a very good pressure to run in these tires. Avoid big heading changes just before stopping, because that can skew the temperature readings especially on the front tires.

I've done this on most of my vehicles to validate the best tire pressures for each vehicle. I have even done this on my car hauler, empty and loaded. Of course once you know the correct pressure you still need to periodically check the pressure to be sure it's staying the same… unless that is you have a vehicle with TPMS… which thanks to Big Brother, we will all have in our new vehicles within a few years…

Good luck… GUSTO

 

Good information, GUSTO. Thanks.