Home Forums Gear Hunting Trucks and Four-Wheel Drives At what tread depth do tires become "unsafe"?

Thanks for all of the advise/input!

I sucked it up and bought a new set of Michelins for about $200 per tire installed and road hazarded. I figure that I have three vehicles that use the same wheels and tire size, so I can move them around if I need to.

2004 Ford Explorer Sport-Trac, my hunting rig, with 140K miles.
2005 Lincoln Aviator, my daily driver, with 160K miles, where the Michelans are.
2005 Mercury Mountaineer, my leave it in Colorado car with 190K.