Air Rams: How Bicycle Pumps Work

man pumping air to bicycle tire

Bicycle riders use small and handy bicycle pumps regularly. This is probably why you’ll always see an air pump strapped to a bicycle. If you use one regularly, do you know how they actually work? The objective of any bike pump is to force air out of the air rams or valves and into the tire to increase the tire pressure to an appropriate level. Although there are three types of manual bicycle pumps, including the Foot Pump and CO2 Cartridge, we will only discuss the manual Hand Pump, which is the most common bike pump used.

Intake and release

Any bicycle pump is basically just an air piston. The long plastic or metal shaft that is between the handle and base serves to hold air. When you pull the handle outwards, the air is sucked in through the intake valve, and the piston gets filled with air. When you push back the handle inwards into the pump, the air is pushed out of the piston, into the hose, and out of the fill valve. The pump handle you hold is attached to a long and thin rod going into the main pump shaft. Inside the pump, at the end of the rod, a plunger assembly creates an airtight seal so that when you push the handle back inside, all air is pushed out of the hose.

Valve or air rams

Bicycle pumps can use several types of valves or air rams. These pneumatic natured types of valves correspond to the matching valve on the bike tube. When buying bike tubes and bike pumps, make sure both are compatible with each other. This is because when you put the pump valve into the tire valve and lock it in place, it allows the exiting air from the pump to be pushed directly into the tube, rather than exiting and spraying out into the open. Some manual hand bike pumps have a pressure gauge attached. This allows you to read the tire pressure currently inside the tube so you can pump to the needed pressure level.

Word of caution

Because of the sensitivity of the valve inside the pump, when lubricating a pump, use only heavy oil or light grease. Don’t use automotive axle grease.

Master Mac 2000

When it comes to air rams, air treatment valves, and other pneumatic valves and systems, you can call MasterMac2000. Established in 1989, the company has grown to become one of Australia’s largest privately-owned distributors of valves, cylinders, power clamps, GR8 tooling, vacuum systems, and American cylinders. Call Master Mac 2000 for enquiries on 07 3344 4711 or visit to view their product lines.

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