In WaGuy78's Maxxis front tire thread, there was a comment about tire wear. It led me to think about this a little, and rather than losing the subject in that thread, I figured I'd start a thread of its own: the SI rear is just as awesome as far as traction goes BUT i'm not real happy with the wear so far. two rides(about 150 mi) and its 1/3 gone ncmm - What kind of criteira are you using when you describe the tire as "1/3 gone?" Are you saying the knobs have lost 1/3 of their height, or that the edges are rounded off to some level? Do you use different criteria in assessing a front vs. a rear tire? I'm curious to hear more from others about what you consider to be "ready to change 'em" levels of tire wear.