Gas Stations

• Nearly every gas station has an air pump, and many of them be fed coins, usually quarters, to be used. This option is ideal because not only can you check the air pressure, but refill the tires at the same time. Simply remove the cap from the tire's valve stem and attach the air pump. A ruler will slide out and display air pressure.
  
  

Pencil and Digital Tire Gauges

• Pressure gauges are relatively easy to buy. Digital gauges will cost slightly more, but will give you a more accurate PSI reading. Pencil gauges work like the air pumps at gas stations, as a ruler will slide out to the appropriate PSI number. Both gauges use the same process. Unscrew the valve stem cap and attach the gauge. Electronic gauges will have to be turned on first, and the battery will need routine checking.
  
  

Tire Inflators

• Tire inflaters, like those manufactured by Slime, also will give you a PSI reading. Like an air pump at a gas station, you also can re-inflate a tire while checking the reading. Like the above two options, the tire inflater must be attached to a tire's valve stem. Since inflaters can be small and portable, they can be kept in the trunk for roadside emergencies.