Driving with low pressure, increase the heat inside the tire. This may lead to a separation of the tire, which in turn leads to wear and breakage of the thread. The low pressure also leads to rapid wear of the tire sholders, which reduces her life Excessive tire pressure results in instability and difficult control of the vehicle. If the tire had an impact or friction, it is therefore much easier to get a break or so-called "balloon". If you need to stop suddenly with overinflated tires, the car will slide more than normal, leading to a shortening of her life due to wear of the midline.