There are many things to take care of e.g. tire pressure, wheel alignment, the wear
bar, etc.
Tire Specifications
There are two specification sets for tires including the tire
manufacturer's specifications and the vehicle manufacturer's
specifications. Whenever you take your car to a tire shop to get the
tires changed, they have to meet these specifications by law. You can
get a tire that goes above these specifications, but never below.
The vehicle manufacturer’s specifications include speed rating, load, and size. It is located on a sticker on the driver’s door jamb of the
vehicle and in the vehicle owner’s manual.
The tire manufacturer's specifications include the tire size, load,
pressure, temperature, speed rating, and tread wear. The tire
manufacturer's specifications indicate what the tire is made to
withstand. These specifications can be found on the wall of the tire
itself.
Tire Pressure
Probably the most important number for the common person to recognize is the recommended tire pressure on the vehicle manufacturer’s specifications on the driver’s door jamb sticker. (The tire manufacturer’s specifications on the tire itself include the maximum pressure that the tire can have, yet the maximum pressure isn’t necessarily the best pressure for the vehicle).
Tire pressure is measured in PSI (pounds per square inch) or KPA
(Kilopascals) which are simply units of measurement for pressure.
(Pressure is a force distributed over the surface area)
Wheel Alignment
Tires can wear rapidly if they are not aligned properly, or the vehicle
can pull to one side while driving.
Wear Bar
The wear bar is a horizontal bar molded into the tire between the
treads. The wear bar indicates safe tread depth. It is usually about
1/16 of an inch measured from the valley of the tread, but not as high
as the tread itself when the tire is new. As the tread wears down, the
wear bar becomes more visible. When the tread is even with the wear bar
the tires should be changed.
