Product Test: Tyre Inflators
A portable tyre inflator gives you control over optimum tyre pressures. Gary Stretton picks the best
160 Having a portable tyre inflator on board can save a trip to the garage. We pick the best
Aflat tyre, leaky rim or slow puncture can halt you in your tracks just when you need to get going the most. So having a portable tyre inflator on board can be the difference between 10 minutes delay or a wheel change and a trip to the nearest garage. And it’s essential for adjusting tyre pressures whenever you want to go off-road.
Small pumps available from filling stations for less than £20, claiming high inflation pressures, are false economy.
All 4x4 tyres take longer to inflate to their specified pressures than smaller car tyres due to their size. For a tyre inflator, 4x4 tyres represent a challenge because the volume of air required is large and the typical continuous running time of a small pump before it overheats and cuts out to protect itself can be short. A long wait then ensues while it cools down. 250 psi isn’t a tyre pressure figure to base your purchase on, it just provides a selling point based on a big number to impress.
Instead, look for litres per minute figures (L/min). The bigger that number, the faster a tyre can be inflated. It’s also worth noting that this test was conducted using a 12 volt power source with a constant output of approximately 12.5v. With your vehicle’s engine running, an auxiliary socket might receive slightly more than this, which is enough to power the inflators at a faster rate. It might also cause them to run hotter over extended periods. With that in mind, I suggest a margin of error to be factored in. The inflation figures from 0-30 psi quoted should be taken as subjective for the purposes of the test. If you only need to increase a tyre pressure by 10 psi, for example, then the inflators tested can be expected to perform much faster than on test. Lastly, jack up a vehicle with a flat tyre before you attempt to inflate the tyre, otherwise your inflator is trying to raise the vehicle’s weight, too.