PUMP IT UP By Dick Eussen ARB has introduced some great innovations for 4WD owners, including air compressors. The latest is a clear winner and was first pass the post against a field of 15 competitors in a recent magazine air compressor comparison test.
An air compressor is very handy in the bush and most of us are familiar with small units available from bargain-prize auto stores which do a creditable job on car tires and air beds, but fail miserable on large 4WD tires. The modern range of 4WD suitable air compressors are something else and can be life saving in the bush. Every 4WD should have one on board.
On a recent trip to Cape York we got well and truly dry bogged in heavy sand. It is not hard to do in sandy country, especially if your have skinny tires, or they are pumped up too high. We got out by dropping the tire pressure to 15 psi and pumping them up with my newly acquired ARB portable compressor when we got to firmer ground. You can use reasonably high pressure for running on the black top, but on corrugation, bush tracks and particular in sand, you need to drop the tire pressure. Not too much though. I have dropped down to 10 psi for skinny tires that were supported by a tube for a short distance, but I don’t recommend that you go much lower than 18 psi and certainly no below 15 psi for fat tires, otherwise there is a real danger that they will roll off the rim. Once you are out of the bog zone inflate the tires to the proper recommended driving pressure.Portable compressed air gives you the ability to freely deflate and inflate tires to suit offroad conditions, or if you need to repair a tire. If you have a good tire repair/puncture kit you can easily get out of trouble with a bit of sweat — and cursing.
An inner tube to fit the wheel/tire makes bush repair of tires much easier. I have had several punctures a day while hunting in thick bush country — now the southern area of the Kakadu National Park. Arnhem Land is another area where I have had some real bad times with punctures. In those days we only had hand pumps and skinny tires. I reckon we are spoiled now, especially with such compact high performance units as the CKMP12.The ARB Portable Air Compressor is designed and made in Australia to suit our unique conditions. It is an ultra compact unit that is attached to the inside of a heavy duty high impact polypropylene tool-style carry box for easy transport and storing. The box also holds a 6m air hose fitted with corrosion-resistant one-handed push-lock quick connect/release couplings, and an accessory kit containing a high-flow tire filler with integral stop valve, Schrader valve, and extra nozzles for air beds, sport ball inflator etc. Full instructions and warranty come with the unit.
The unit is attached to the battery with automotive grade alligator clips. There is an illuminated on/off switch on the unit itself. The unit switches off when the tire filler is disconnected from the valve, and back on again when it is reattached. It also shuts down if the hose is kinked. It is a neat little trick. The compressor inflates big 4WD off road tires with ease, and in test it pumped up to 33 psi in two minutes. Average pressure for offroad tires ranges from about 35-40 psi.
Pumping the tire to 45 psi took three minutes, probably because of back pressure as the tire pressure increased. Try that with the bargain-barn compressor…
The CKMP12 compressor has the highest-rated flow for a portable air compressor in its class. It is constructed of light weight, high strength engineering-grade materials including military and space age components. The unit is fully sealed against moisture and dust. The motor is 100% ball-bearing equipped, has a unique linear brush pre-load system for long life, low heat, and is fairly quiet in operation. If used too long and it begins to overheat, a thermal cut-off switch will switch it off before any damage occurs. The illuminated isolating switch is great for night use and warns and protects the user from accidental sparks when attaching the alligator clips to the battery. The heavy duty Maxi-fuse leads have professional in-line circuit protection.
The unit motor has a hard-anodized bore and Teflon impregnated carbon fibre piston seal for reduced friction and a trouble free life. The compressor piston is fitted with a German made high shock rated cylindrical roller bearing, while a high density and high flow washable sintered bronze filter element ensures air quality. The unit is also equipped with an over-pressure safety valve as back-up protection against pressure switch failure, thermal over pressure generated in a hot vehicle, or the accidental connection to an external high pressure source.
Summary This is an ideal best air compressor for off road and camping use, being portable and having a high flow rate of air. Parts are available. A trouble shooting and service guide is in the manual. Make sure to read the instructions before use.
Specifications Current draw: At 0 kpa/psi – 13 amps. At 200 kpa/29 psi – 22.9 amps. Flow rate (under load): At 200 kpa – 61.6 litres/minute. At 29 psi – 2.18 cubic feet a minute. Visit www.arb.com.au for details on the unit and other ARB products for your fourbie, or visit your local ARB store.