tire guaruntees?

Does anyone know why my el cheapo 50,000 mile tires (in the back, RWD) are so worn down after only 13,000 miles? and how anal are shops aobut honoring the warranty? And before you ask; no i haven't been doing burnouts all day every day. Shit my car barely has enough power, i've always kept them properly pressurized, the wear is even, its just the the tread has gone down FAST! Even with hard driving, which i havent been doing, i expected these to last 30k miles.

If you didn't rotate that would cause excessive wear.


Unless it it's a major tire company, these warranty are often more of marketing tool.