We have a 2004 911 Conv. Has the optional larger wheels (17" front - 18" rear).

Wife was driving the other day and the rear driver tire went flat. Only around 12k miles on the tires (Hankook XS tires). Turned out that the inside tread has fully worn through to the cords and it blew. The outside portion of the tires looks great. Passenger rear is just as bad.

Fronts look OK, so it seems like the alignment I had done last February (2013) was off from the get go. Shame on me for not checking the tires carefully periodically. I had looked them over, but was just looking at them from the outside of the car and didn't notice the horrible wear on the inside edge.

What are the alignment specs for this model? I want to make sure I have them with me so I can confirm the settings in their machine are correct.

How long should an alignment last in this car?

Is the alignment something you should only do at the dealer? I figured any competent shop could handle the alignment - since they all just plug the model into their computer and adjust accordingly.

It's my wife's car...she's not an aggressive driver and it sees no track duty.

 

GT3 Street alignment:
Rear Axle:
Camber: -1.50 degrees +/- .10 degrees
Toe: +08' +/- 05' Total Toe: +16' +/- 10' axle angle: 0' +/- 10'
Front Axle:
Caster: +8 degrees +/- 3 degrees
Camber: -1 Degree +/- .10 degrees
Toe: +03' +/- 03' Total Toe: +05' +/1 05'


Keep in mind, inside wear is not necessarily associated with neg. camber, it's more associated with "toe out" setting. Remove a little "toe out" and you'll get a bit more life.

 

Here are the numbers for the 2004 GT3, for both RoW and USA. Front axle height: 115 + 5mm (115 to 120mm) Rear axle height: 128 + 5mm (128 to 133mm) Front axle: Toe unpressed (total): +8' +/- 2' Toe difference at 20° lock: -1°30' +/- 30' Camber: -1° +/- 5' Max camber difference, left/right: 10' Caster: 8° +/- 30' Max caster difference, left/right: 40' Rear axle: Toe per wheel: +13' +/- 2' Max toe difference, left/right: 5' Camber: -1°50' +/- 5' Max camber difference, left/right: 10'

Porsche Factory numbers

keep in mind for the track only. Bet it will eat the tires.

Here are some numbers from I Believe Apex Competition:

Here are numbers for a track/street compromise:
Front axle:
Toe total: +4′
Camber: -1.7º
Caster: 8° +/- 30′
Rear axle:
Toe total: 33’ +/- 2′
Camber: -1.8°


Optimize for track use:
Front axle:Toe total: +5′
Camber: -2.5º
Caster: 8° +/- 30′
Rear axle:Toe total: 32’ +/- 2′
Camber: -2.4°

 

Rear tires on Porsche's normally wear twice as quickly as the fronts and usually last 12k - 15k miles depending on the driver. Sounds like you found the max mileage on those tires. Messing around with alignment settings may affect your car's handling.