I just discovered a surface split on the sidewalk of one of my tires. My CR-V has only a little under 13,000 miles so I'm not necessarily inclined to toss all 4 just yet - even if they are the Bridgestone Ecopians that came with the car. I think the split came from some bad tire contact issue that happened recently, although I have no evidence to prove that as I didn't check the tires at the time. In any case, would it be okay if I just replaced this one damaged guy, or is 13K of mixed highway and local driving too much wear on the tires for that to be good?