Mike Allen over at Popular Mechanics put together a handy list of the top five reasons for tire failure. We figure it's important stuff since, you know, your tires are pretty much more important than any other part of your car — they're what the whole rest of the vehicle rides on. Believe it or not, there's more that can be wrong with your tires than just underinflation, so check out the list below the jump. 5.) They're Damaged So... you're telling us damage is bad? Wow. Guess we'll have to stop carving "Jalopnik was here" with a knife into people's tires and calling it a PR stunt. Actually, a careful inspection for missing chunks of rubber, bulges (unsightly or otherwise) and evidence of curb or debris damage can keep you from having to call a tow truck when you're miles from home. 4.) They're Deteriorated Not to be confused with damage, deterioration happens over time due to atmospheric conditions — mainly ozone in the air acting on the rubber to produce dry rot. Deterioration can be sneaky, resulting in weak spots that can lead to a blowout. Look for spiderweb cracks in the sidewall and a dull, dusty appearance to the rubber. 3.) They're Overinflated Contrary to what your friend Jeff told you, inflating your tires well beyond the suggested pressure will not increase your fuel economy to 95 MPG. 2.) They're Underinflated The corollary to overinflated, this condition is not to be confused with a "flat" tire (which is also bad). An underinflated tire doesn't just decrease your MPG, it can also lead to irregular wear. Want to know what the right inflation pressure for your tires is? Don't use the number on the tires — that's just the tire manufacturer's suggested maximum inflation pressure. Instead, check the sticker on the driver's door frame or inside the glovebox for the right pressure. Also, check the owner's manual. 1.) And the number one reason your tires fail is... (it's almost too obvious, but place your bets and check it out here.) In all seriousness, the points themselves may seem obvious, but PopMech does a good job of explaining the hows and whys behind their top five failure modes, and they might just clue you in on something you've forgotten.
I didn't think the old over-inflating adage was relevant with radial tires. The cross-hatched belts tying to the sidewalls prevent the tire from bowing across the tread, and the extra air goes into sidewall deformation.
From what I've read, the biggest issue with over-inflation is valve-stem failure and lip cupping which can lead to leakage (and thus eliminating the over-inflation issue).