WHAT IT ALL MEANS

01 FLOW RATE

Maximum pressure is the absolute highest pressure the compressor can pump into a tyre, typically they’re all in the triple-digit figures, so are almost irrelevant for 4x4 use. Flow rate is far more important and tells us how much air the compressor can pump. A compressor than can flow 200L/pm (litres per minute) will pump up a tyre twice as fast as one at 100L/pm. This can also be measured in Cubic Feet per Minute, or CFM.

02 DUTY CYCLE

Duty Cycle is used to describe two things: how long the compressor can run, and how long it needs to rest. Different companies use different methods, but you can roughly compare them. Percentage means how much cool-down time it needs in an hour of operation. So 50 per cent duty cycle is 30 minutes on, 30 minutes off. Others are measured in time – where the manufacturer states 40 minutes, it’s implied it’ll need to rest for 20 minutes.

03 MAX CURRENT DRAW

While average current draw lets you know how much power something will chew, maximum current draw is far more useful for knowing how strong your electrical system needs to be to deal with the stresses. It factors in the peaks in consumption you’ll find pushing against higher pressures, dealing with heat, or the large start-up loads. The higher the max current draw, the more load it’ll put on your four-wheel drive’s electrical system.