Underinflating a tire causes excess wear on the outer edges of its tread. Underinflation also increases the chance of a blowout or even a fire from excessive heat buildup resulting from increased flexing of the tire. Overinflating a tire causes excess wear in the centre part of its tread. Overinflation makes the tire more susceptible to damage from potholes or other road irregularities and increases the chance of tread separation and tire failure.