Valve Cap: An Important Safety Element

A tire valve, millionfold in use, and mostly completely unnoticed, is an important safety element in every vehicle. A good valve cap with a built-in rubber seal is a basic requirement for the long-lasting function of a valve, and fulfills several functions at once:

  • It prevents the intrusion of dirt into the valve interior. Dirt particles can prevent the closing of the valve after filling/checking tire pressure and lead to leakage.
  • Corroded valves are often not tight or do not function. A good valve cap prevents the intrusion of moisture, and so prevents corrosion and damage to the valve.
  • Dust, inside the tire or in the air used for filling, can settle in the interior of the valve during inflating or deflating and prevent the closing of the valve core. A sturdy valve cap with a built-in washer seals the valve securely, and prevents a gradual loss of pressure.

Valve caps save money

When the tire pressure is too low, it is not only a safety risk but it also costs money. A 0.6 bar (9 psi) drop in tire pressure raises fuel consumption by 3%. And when there is 30% less tire pressure, the life of the tire is halved. A good valve cap can prevent air loss from a slow leak; and so helps to save money. Therefore, never use a tire valve without a valve cap!

Requirements of a good valve cap

Material: metal or high-quality synthetic material 
  • Can reliably bear insertion force
  • Has the necessary solidity for proper sealing
  • Can be dismounted even in difficult conditions
  • Doesn’t become soft or crack in warm temperatures
Built-in rubber seal
  • Seals against the intrusion of dirt and water
  • Prevents corrosion of valve interior
  • Takes over the sealing function when valve core is dirty
Corrosion protection
  • Nickel-plated brass caps prevent corrosion of the valve thread

Special models

Aluminium and brass don’t like each other — the combination of brass and aluminum leads to electro-chemical corrosion
  • Therefore, only use the original aluminum or plastic valve caps with aluminum valves ( e.g. with Tire Pressure Monitoring Systems/TPMS) 
  • Also be careful with aluminum  caps on standard valves — corrosion can cause the valve cap to seize up on the valve; forcible dismounting can destroy the valve

Green valve caps are often used to show that the tire is filled with nitrogen. Other colours are also used for special purposes. 


Valve extensions make valves on twin tires or on awkward rims more easily accessible. Please note: Don’t use metal extensions with Snap-In valves. The increased mass and the resulting centrifugal forces can damage the valve due to over-stretching. Special plastic extensions are available for car valves 


Double Seal Valve Caps V2B: The cost-saver for commercial vehicles. Tire pressure has to be checked regularly especially on commercial vehicles. This is sometimes not so easy with up to 18 wheels per rig, valves which are difficult to access, and extreme dirt and icy temperatures.This often leads to the tire pressure not being checked regularly.

The results are a decidedly increased safety risk, a higher fuel consumption, and a noticeably shorter tire life. The ALLIGATOR Double Seal Valve Cap V2B provides a remedy. It doesn’t need to be removed for filling or for checking the pressure, saving you time and money.