[quote=71GP76TA;4309815]Gotchya beat
.... I'm sitting at 107k and some change... I'm sure it'll be 108k by the end of the week.
BTW - I'm only getting 15k-17k out of a set of tires...
[/quote
I copied and pasted the probable reasons of why your tires are wearing rapidly below:
Negative camber front and or rear is what is skinning the inner shoulders of your tires. Measure your rear ride height from the lower lip of the wheel rim up through the wheel center to the painted edge of the guard / fender. My guess is you'll get a result in the range of 585mm on the rears. The result is a high negative rear camber that is causing inner shoulder tire wear.
The contact with the strut is NOT wearing out your tires. The strut surface is smoother than the pavement. Metal contact with tires causes heat build up and the tire to get greasy. Much like the tire boogers created from a burn-out, a tire than rubs hard on smooth metal will heat up and be greasy to the touch even after it cools down. Rub your fingers across the tire and you'll get a dirty / dusty result if they are healthy. If they have been heated by smooth metal against rubber friction they should leave a greasy residue on your fingers.
Without inspecting your car here are my guesses based on what you have posted and the results of being under who knows how many GTOs at this point.
1. Rear ride height is under 590mm causing significant negative rear camber. This can be verified by ride height measurements and a the negative camber reading from the alignment machine.
2. The LARGE contact spots of the front struts are caused by excessive play in the front suspension. The vehicle appears to have good alignment while in a static position on the alignment machine, but the wear pattern on the struts is larger than normal and out of the ordinary while tire wear is excessive. The solutions and inspections:
a. Radius Rod Brake Test
b. Strut Mount Inspection
c. Front Ride Height Measurement
d. Outer Control Arm Bush Inspection
c. Leaking Strut Inspection -- is there only in the lower spring seat?
If you could get your GTO to a Pontiac / Pedders Dealer they have more information and knowledge of these vehicles than most. They can perform all of these tests and inspections with you standing side-by-side with the tech. If not have the Dealer of your choice follow these steps and call us if they have any questions. My guess is that your vehicle needs strut mounts, radius rod bushes and rear coils with a four wheel alignment to spec or you will continue to eat / wear out tires rapidly. There is no reasons to expect that if the car was aligned to spec and ate tires and the tires were replaced and the car aligned to the same specifications that the new tires will last one mile longer. Either the alignments were wrong during the first set of tire use or there are issues mechanically with your car allowing the alignment to wander out of spec under load. A properly aligned and healthy suspension GTO does NOT eat tires or rub the paint off struts in a 2.5 inch pattern.
Not to throw gasoline on a fire, but... The GTO squats like a bandit under hard acceleration. Repeated hard starts will skin the shoulders off a rear tire in a very short period of time with a rear ride height under 590mm. If you like to do burnouts and have OE rear coils the result will be short tire life. That probably isn't the case here.
Get these well known suspension short comings fixed on your GTO and your tire wear will more than double, mine did....................................
A company called Peddars makes the aftermarket parts to get your suspension back to where it should be.
Another thread about tire wear and suspension pieces;
http://forums.maxperformanceinc.com/...=tire+wear+gto