The road I use to get to and from my house is full of clay and, when wet, the grooves of my ATs do get filled. We're talking about 4" deep, squishy, sticky mud. And, yeah, it's kind of like riding on slicks at that point. However, I was able to tow my Ch**y van down that road the other day even with the mud caked on the tires like donuts. Guess it has a lot to do with the consistency of the mud at the time and how you drive it. I too sometimes have to punch through some of the muddiest areas with a little speed. When I don't, I can usually power grind down to some solid footing to get out. That's another thing. A narrower tire seems to work better. Mine are LT215x15s. --Mike D.