Try a search here on roadtec and you'll pull up a few relevant posts.
My '07 GT came from the factory with Z6 tires. They handled fine wet or dry, highway or twisties. But the rear was completely down to the cords at 4,700 miles, while the front still looks new. The rear also has a solid tread band in the middle of the tire, meaning there are no tread wear indicators to check.
I check both tires at every fuel stop, looking for wear, nails, or anything else unusual. At one gas stop they were fine. At the next, less than 200 miles later, the rear was just starting to break through to the cords in one spot, and very thin in another.
Fortunately, I was about 30 miles from Ozzie's BMW in Chico, CA. Unfortunately, it was a Monday and they were closed. I figured I could stay the night and hit them first thing in the morning. But I called anyway, and to my surprise Ozzie answered the phone. I rode in, he called in one of his mechanics, and they had me back on the road in about 2 hours. All they had was another Z6 rear tire, which should last me just about 2 1/2 weeks based on my current riding plans.
Just long enough to get a set of Avon Storm-ST tires ordered.
'13 Dark Graphite Metallic K16GTLD, 24K miles and counting...
'09 Magnesium Beige Metallic K13GT, 60K miles miles and counting...
'02 Mauve Metallic K12LTC, 106K miles and sold
BMWLT#145, IBA# 366, MOA# 111996, SCMA# 24032
All lower 48 states plus Alaska on the K13GT in two weeks . . .
Some people see the gas tank as half empty. Some see it as half full. All I care is that I know where the next tankful is coming from...