A flat tire doesn’t have to flatten your spirit. Like car tires, bicycle tires occasionally need to be refilled using a pump. Understanding how to use a bicycle pump can get you rolling again after an unfortunate flat on your next group ride. Bicycle pumps use either Schrader- or Presta-type valves, and can be portable or floor-based.
Tire Valves - Bicycle pumps correspond to the valve located on your tube, which sticks out of the rim for easy refilling. The narrow Presta valve is common on road bicycles, while the slightly wider Schrader valve is usually found on mountain bikes and children's bikes. Many bicycle pump heads allow the user to switch between the two sizes. Unscrew the cap at the end of your valve, and place the pump head over the valve. Once it's seated firmly, there should be a small lever on the pump head that tightens the connection so that no air escapes while pumping. Your tire will have the manufacturer-recommended PSI range stamped into the side.
Bicycle Pump Types - In addition to valve type, pumps come in two main varieties. Floor pumps are more powerful bicycle pumps with a flat base for leverage. Portable bicycle pumps use only a handle, and are smaller for easy carrying. They're less powerful, but are there when you need them most. Be careful not to break your valve stem when using a portable pump, since there's no flexible hose to prevent sideways pressure on the stem.