What makes an all-terrain tire different from a cheap tire, snow tire or expensive ultra-high performance tire? Part of the answer lies in what industry folks like to call "tire geometry". Irregularly shaped patterns and deep grooves combine to whip snow, mud, and sand away as the tire rotates on the turf. This lets the tire grab the most terrain possible-the good traction you expect from an all-terrain tire. Cheap tires are built to simply hug the road. The grooves aren't designed to toss mud and debris, and aren't meant to do so. The all-terrain design is built to withstand conditions that would send normal cars spinning out of control, or grinding to a dead stop in mud or snow. It's also the reason why running all-terrain tires on pavement isn't such a good idea over the long term--they wear down faster on the hard surfaces and the heat generated by driving on them.