I'm pretty sure that I read somewhere that the Goodyears MT/R's have 2 ply sidewalls. I think it was in a tire comparison in Peterson's 4 Wheel & Offroad. The testers were initially worried about puncturing the side walls and commented that this was a problem with older Goodyear M/Ts. They ended up saying that they thought the MT/R was pretty tuff. Goodyear claims (like Pro Comp) that they use some type of criss crossing plies made of some kind of special compound that resists puncturing. I'm not a big fan of Goodyear tires either. I have heard that the MT/R produces more road noise than some other, more aggressive tires. But, the test in the link Schlud posted above indicates that they are fairly quite.