panamera rear tire wear

[phrogiii]

My 2012 Panamera went through the rear Pirelli P-zero tires in 7100 miles. At $372 apiece, that's $.11/mile. (the same as $2.80/gal gas at 25mpg!)... so I tried Michelin Pilot Sport A/S 3 tires for their UTQG 500 AA A wear rating. The rears were 255/45ZR18, not the stock 275/45R18 (7% narrower)... I drive 10,000 miles a year on interstates and would prefer more straight line tire life to better handling in curves... these harder tires were acceptable to me, BUT, the insides of both rear wheels developed cupping (3" pitch, with a very annoying howl) at 15,000 miles... They were ready for replacement after 20,000 miles due to the cupping wear... 

 

I want to try zero camber on the rears... This raises 2 questions:

 

1) Camber is spec'd to be between -1.8 and -1.3 degrees... What is the range of adjustment?... Can I even get to zero?

 

2) Toe is spec'd to be between 0.00 and 0.16 degrees... Assuming I can get to zero camber, what toe should I shoot for?

 

Thanks in advance for any advise...

[RFM]

Hard to tell here, all values in the range of the specs. give different situations in connection with road handling, load, tire wear, etc. I would start with the right tire choise and an average value of the specs. as camber -1.5 toe 0.8, all this with a full fuel tank. If you can live with these settings, you can go even sharper in the future.