Originally Posted by roundel335
This is true. Don't expect high mileage from Z-rated tires - getting 15K+ from them is actually pretty good. The rubber on these tires is softer than non-Z-rated tires, and unless you buy some of the newer designs with assymetrical tread compounds with higher UTQG ratings, you generally won't see more tread life than what you're currently getting.
But these are basically highway miles.
I get 20-25 thousand miles out of Z rated tires with autoxs.