7. That tire’s still got some life in it


We’ve all heard variations of the old warning that 90% of tire failure takes place in the last 20% of tire wear. I’m not here to argue with the truthiness of that statement since catastrophic tire failure is still relatively rare – even with a mostly used up tread. Instead, let’s consider all the other things that tires do to keep your bike shiny side up. Obviously, the deeper the grooves in the tread, the better the tires can channel water away and prevent hydroplaning. Folks who live in areas where it doesn’t rain much don’t get off scott-free, however. The grooves also help the tread to maintain contact with the pavement in dirty or sandy conditions.

Tire manufacturers expend a ton of effort in designing tire profiles. Since a tire’s shape affects a bike’s turn-in characteristics and its willingness to change lines in a corner, if a front tire is worn on the sides, it can become less willing to hold a line different from the one that fits the worn profile. Similarly, applying the front brake while leaned over on a worn tire can cause an abrupt change in attitude, like standing up and sending you wide at the worst possible time. Also, a rear tire worn flat in the middle will tend to self-center as the bike transitions from leaned over to upright, rather than letting you control the transition.

Don’t cheap out. It could get expensive. Also, new tires add a great smell to your garage when you first walk in to it.