Finally installed the second pair of PR3's today. Rear was showing cords, front was bald (as in smooth) on the sides, and almost bald in the center. It was really squared off too. I removed a 180/55 PR3, so today I installed the 190/55 PR3 to see how that goes. Always use the stock size front.
I really don't see how anyone can get 2 rears for each front, unless you're doing burnouts, or never use the front brakes and never push the bike in corners.
Saw the most mileage out of these PR3's so far :
Brickstones = 4,897 miles. Front shot (cupped, squared off), rear still OK for a spare.
Pirelli Angel ST's = 7,307 miles. Rear showing cords, front OK for a spare.
PR2's = 10,804 miles. Rear showing cords, front cupped, down to wear bars, causing front end shimmy.
PR3's = 11,863 miles. Rear showing cords, front bald on sides, squared off badly.