Most air chucks use a closed-flow design. This type keeps air from flowing until it is pressed or locked onto the valve stem. These are generally the best choice for an air compressor that features a tank as the compressor doesn't have to work to keep the tank filled as you work.
Air chucks secure to the valve stem in a few ways. Clip-on and push-on are the most common designs used. As the name implies, a push on air chuck requires you to push it down on the valve stem to begin supplying air. Clip-on models work similarly but feature a clipping mechanism to keep it in place, reducing the risk of letting air leak out. A third type screws onto the valve stem. Screwing into place creates a superior seal but is considered more trouble than it's worth, considering clip-on chucks are very reliable.
• You’re bound to lose, misplace, or lend out air chucks. It’s worth investing in a few to prevent yourself from winding up in a bind.
• Air chucks are relatively inexpensive, but losing them can still be extremely frustrating. It’s worth investing in a small case or pouch to help you keep track of them.
• You always want a tire to be filled to the appropriate specifications to prevent excess wear, promote performance, and reduce the likelihood of blowouts. Therefore, you’ll want a high-quality tire pressure gauge on hand, if not built right into the chuck.
• Remember, there's a reason a tire went flat. It's best to keep tire or inner tube repair equipment on hand so that you can deal with any punctures.