Here are some Tire FAQ
If tire pressure is too low, then too much of the tire's surface area touches the ground, which increases friction between the road and the tire. Thus, your tires wear out earlier, and they could also could overheat.
A sign of low tire pressure is a squealing sound when you corner your vehicle while driving.
Loss of Air:
A tire can actually lose up to half of the air pressure and not even appear to be flat.