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A bicycle pump is a type of positive-displacement air pump specifically designed for inflating bicycle tires. It has a connection or adapter for use with one or both of the two most common types of valves used on bicycles, Schrader or Presta. A third type of valve called the Dunlop (or Woods) valve exists, but tubes with these valves can be filled using a Presta pump.[1][2]
Several basic types are available:
In its most basic form, a bicycle pump functions via a hand-operated piston. During up-stroke, this piston draws air through a one-way valve into the pump from outside. During down-stroke, the piston then displaces air from the pump into the bicycle tire. Most floor pumps, also commonly called track pumps, have a built-in pressure gauge to indicate tire pressure.
Electrically-operated pumps intended to inflate car tires (as available in most service stations) can in principle be used to inflate a bicycle tire if the right type of connection is available. Some such pumps are designed to cut off before a suitable pressure (much higher for a bicycle than a car tire), and will much under inflate the tire. Others may not cut off, but deliver a high rate of flow to fill the larger car tire, with a risk of over inflating and bursting a bicycle tire unless it is stopped with split-second timing.
Inflating tubeless tires requires an initial surge of air to seat the bead, and specialized pumps are available specifically for this task.[3]