For instance, tires that show a lot of wear at their edges might be underinflated or just subject to lots of hard cornering. If the tire's center is worn, the tire may be overinflated, or you might be spending too much time riding in a straight line. Most front tires will show some evidence of cupping or scalloping, especially if the bike's ridden hard. Cupping is a more or less normal part of tire wear; however, it can also indicate the tire is severely out of balance or there's a mechanical problem with the front fork. In any event it can become so severe that it has a detrimental effect on handling long before the tread has reached its minimum thickness.