These are our cutting-edge tire checking tools. On the right is a stick-type tire gauge. They're cheap enough to keep one in every vehicle, plus I have a couple knocking around the garage. If the stick type isn't your speed, there are also digital and dial-type gauges available.
On the left is a standard US quarter. In addition to being used to buy things, it also makes a handy gauge to measure the remaining depth of your tire tread.
Flip George head down, and insert him into the grooves in your tread. If you can see the top of his head, it's time to start shopping for new rubber.
Tires should wear evenly. The slanted wear on this tire indicates a suspension issue requiring professional correction. If fixed in time, the tire can be saved.
See the excess wear on the left?
If suspension issues are not corrected, they lead to rapid tire degradation as shown in the above two pictures. At this point, driving on these tires is quite dangerous.
Improper tire pressure is one of the most common and most serious causes of tire failure. Both over- and under-inflated tires can bring about dangerous situations. Over-inflated tires wear more along the center of the tread, and tend to heat up and build dangerous pressures. Under-inflated tires wear on the outside portions of the tread, and break down and fall apart at an accelerated rate.
The manufacturer's pressure specifications are molded into the sidewall of the tire, as pictured above. Pressure is checked by placing the port on the gauge over the valve stem and then reading the gauge results.
On this stick-type gauge, each small mark is two PSI. They can be quickly and easily read with a bit of practice, and stow neatly in the vehicle's glove/storage area. The pictured gauge took a reading of 35 PSI, which is right on for recommended pressure.
Keep an eye on where the rubber meets the road, and keep yourself and your people safe.