Two kits that will (almost) breakdown-proof your vehicle

Our modern four-wheel-drive vehicles, virtually without exception, are far, far better machines than those we traveled with 30 or 40 years ago, the rose-tinted recollections of some of us nothwithstanding. (See here for a direct comparison.) Yes, they are vastly more complex: The average car today has between 25 and 50 electronic control units or ECUs (the Bentley Bentayga has 90)—some linked, some independent—controlling everything from shock absorber adjustment to accident-avoidance braking. But those complex systems have brought us more power, better fuel economy, a huge improvement in safety, and cleaner air—all at once. 

Despite this complexity, vehicles in general are more reliable than ever. Solid-state ECUs are incredibly stable and durable; precision design and manufacturing processes and advances in metallurgy have made engines and other drivetrain components much longer-lasting. A car with 100,000 miles on the odometer used to be noteworthy; these days, beater pizza-delivery Civics with 200,000-plus under their faded paint are as common as Domino’s outlets. When something does go wrong, the car will quite likely be able to tell the mechanic what is is. How long will it be before a car can sense a part about to fail, then automatically log onto Amazon and have the piece waiting at the shop when the self-drive function reroutes you there?

These advances have made overland travel easier and safer as well, even if—to be fair to those rose-tinted recollections—if something does go wrong in the bush you won’t be regapping the points with a matchbook cover if the dwell shifts, or disassembling the carburetor and popping in a rebuild kit if a gasket goes bad. (But since we no longer have points or carburetors . . .)

One thing has not changed, and that is the two types of problems behind the vast majority of issues in the backcountry that bring a vehicle to a halt: tire punctures and dead batteries. (Number three—at least on the road—according to the AAA? Locking the keys in the car.) 

While tires and batteries have also been improved significantly in the last few decades, both are wear items and are subject to the whims of chance, whether it be a jagged root holing a tire or any number of things draining a battery. 

What this means, however, is that with just two kits in your vehicle you can fix the vast majority of things that are likely to go wrong in the backcountry.

• A backup for the starting battery
• An air compressor and tire repair kit

Let’s, er, start with the battery. A lot of people now have dual-battery systems in their overlanding vehicles, so the auxiliary can be used to power fridges, etc. without draining the starting battery. Most of these systems have a switch that will tie in the auxiliary to the starting circuit when needed, thus solving the problem of a dead main battery in a few seconds. If there is no switch, the auxiliary can be physically swapped with the main battery. Since the chances of two batteries dying simultaneously—at least when installed with a proper isolating system—are scant, you’re more or less immune to battery woes.

A dual-battery system with an automatic isolator, such as this excellent National Luna, will virtually guarantee starting power for your engine

If you have only a single battery for all your systems, I have just one word for you: Microstart. These have been around for several years now and I’ve been preaching their gospel to the point of fanaticism, but I still run into people who have never heard of the product and are blown away when I jump-start their dead 3/4-ton pickup with a battery the size of a VHS tape. I have used and abused a half-dozen of them (we keep one in every vehicle) and they’ve performed perfectly. Early on in their history, master fabricator Tim Scully and I wondered if they could be used for field welding. We duly hooked up three in series and produced several excellent beads, after which the trio continued to work perfectly for their intended use. When I called Scott Schafer at Antigravity Batteries he expressed mingled astonishment and horror at what we had accomplished. (Current Microstarts include an overload device that prevents such shenanigans. Blame Tim and me.) In any case, a Microstart will that ensure a dead starting battery will not leave you stranded. Buy the XP-1 if you have a gasoline-engined mid-size SUV, or the XP-10 if you have a big diesel-powered truck, and top it up (on either AC or DC) every four or five months.

The only real alternative to safeguard a single battery is a low-voltage cutout, which will shut off current flowing from the battery if it senses voltage dropping to levels that would make the vehicle difficult to start. While this might be fine as a backup, I've found that a lot of people who install them are overburdening their battery to begin with, for example by running a fridge while still relying on the battery to turn a high-amperage starter. Better to go with a dual-battery system if you have that much draw.

That leaves tires. As with batteries, they’re a lot tougher and longer-wearing than in years past, but still vulnerable to damage, especially when driven on rough roads and trails. Yet I’m surprised at how many overlanders confine their backup tire kit to a single spare and perhaps a can of Fix-a-Flat. We can do better, and all it takes is a compressor and a proper tire-repair kit.

The repair kit is easy. At its most basic you want a plug kit, which will handle the majority of punctures within the tread area, usually without even needed to remove the wheel and tire from the car. But skip the Pep Boys versions and get a good one. This isn’t just tool snobbery talking: plugging a tire involves shoving pretty hard on the reaming tool and the plug-inserting tool. You do not want a cheap plastic-handled tool breaking during the procedure. ARB makes an excellent plug kit with everything you need for most simple punctures. If you want to step up from that and be prepared to handle virtually any tire problem short of a carcass-shredding blowout (including sidewall splits and broken valve stems), get the Exptreme Outback Ultimate Puncture Repair Kit. It’s expensive at $99, but you’ll never have to buy anything else to repair tires as long as you live.

The ARB Speedy Seal kit includes a proper metal-handled reamer and plug inserter.

Once the tire is repaired you’ll need to re-inflate it. While there are air compressors available from $19.95 on up, skip the cheap ones. They fail with miserable frequency, and even when working are so slow that you could hike out, buy a better unit, and be back before your tire is properly inflated. At a bare minimum get one of the ubiquitous Super Flow MV50 units, which are available from around $60. The MV50s have their issues but in general are reliable and reasonably fast, and if you’re a tinkerer there are dozens of web articles detailing worthwhile hacks for the product. 

Personally I prefer buying a better compressor to start with, both for repairing tires and for the much more frequently needed function of airing all four tires back up after airing them down for trail driving. To step up in quality look at the Viair units and anything from Extreme Outback. My current favorite compressor is the blindingly fast ARB Twin, expensive but worth every penny. Use the Twin to air up and you’ll be finished with your own vehicle and a friend’s before someone with an MV50 has done two tires.

The ARB Twin is available either as the portable kit shown here,which includes an air tank for operating air tools, or as a stand-alone unit for hard mounting in the vehicle.

Part of what defines overlanding is self-sufficiency. Making sure battery and tire troubles can’t bring you to a halt will go a long way toward guaranteeing that self-sufficiency—and if you travel far off the beaten track might just save you a sat-phone call and a very expensive recovery.  

Airing down—and up—the pro way

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One of the most frequent questions people ask me is, “What’s the the best thing I can do to improve my vehicle’s off-pavement performance?” Many of them seem distinctly disappointed when I answer, “Air down your tires.” I’m sure they’re hoping I’ll facilitate some expensive and impressive modification—diff locks, external-bypass shocks, three-piece titanium wheels, something that would justify putting a stylish brand sticker in a window. But the fact is that nothing is easier to do or more effective at providing several instant benefits than reducing your normal street tire pressures to suit the immediate conditions. I’ll repeat: Nothing.

First, lower pressure increases traction by increasing the contact area of the tire and allowing it to better deform around obstacles and grip them. Flotation in sand is enormously enhanced with the longer footprint provided by lower pressure (not so much greater width as many suppose).

But the advantages don’t end there. Lowering pressure alleviates stress on the vehicle by effectively reducing the spring rate—the tires flex enough to absorb impacts that would otherwise have to be dealt with by the springs and shocks. That translates to much greater comfort for the driver and passengers.

Finally, the above characteristics contribute to reduced impact on the trail. We saw first-hand evidence of this on a recent crossing of the Simpson Desert in Australia, via the Madigan Line—so-called after Dr. Cecil Madigan, who led the first scientific expedition across the area in 1939. The Madigan Line cuts directly across the huge field of parallel sand dunes that characterizes this part of the Simpson—1,130 sand dunes to be more or less precise. The dunes themselves are stabilized and well-vegetated, but the bare track still needs to ascend and descend each dune, and despite the very sparse traffic on this route the final approaches and crests are often cratered with “hoon holes,” where those who disdain airing down—or even engaging four wheel drive—have left huge divots from futilely spinning tires or frantic, lunging ascents.

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Graham and I actually aired down our Land Cruisers prior to hitting the dunes, on the stretch leading to the old Andado Station, a fine track but well-known for its long stretches of corrugations (or washboard as we refer to them in the U.S.). I reduced our pressure from 40 psi, which we’d run on the paved Stuart Highway to Alice Springs, down to 32, and Graham did likewise (he’d found his tubed tires on split rims at a harsh 50 psi). It took much of the sting out of the sharp undulations and eliminated the skip-fishtailing that can occur with higher pressures. (An Australian writer described those corrugations as “brutal.” All I can say is he needs to see the corrugations on the seven-mile dirt track to our house in Arizona. Or those on the road from Namanga to Amboseli. But that’s another story.)

Once in the dunes, we further reduced pressure to around 22 psi. This is well above the 14 we might run in very soft sand, but it worked perfectly on the combination of flat, compacted inter-dune track and the chewed-up ascents and descents. We even summited the famous Big Red dune outside Birdsville with no drama.

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Once past Birdsville, on the high-speed gravel Birdsville Developmental Road, we re-inflated—and that’s where the catch is for many people who grasp the concept of airing down, appreciate its advantages, but rarely if ever do it.

Why? Because a lot of those people carry a compressor that cost them as much as a couple of pizzas and is about as effective at actually adding air to a tire, despite the “150 PSI!” claims on the box. A single 45-minute session laboriously moving four tires from 25 psi to, say, 28, while their $29.95 compressor buzzes and vibrates in circles like an enraged chihuahua, and that’s it. The thing gets tossed in the bottom of the tools, to be used in the event of an actual flat, if at all. The same people likely used the point of their Swiss Army knife to depress the valve to deflate each tire, another laborious procedure. It’s little wonder they inflate the tires on their new truck to 40 psi and never budge from that.

We knew better. And we were, after all, in Australia, home of some of the best expedition equipment manufacturers on the planet. In Sydney we had picked up a pair of ARB E-Z deflators, and two ARB portable Twin compressor kits (CKMTP12). The single-cylinder ARB High Output compressor on our Tacoma has been working perfectly for several years operating a locker and inflating tires, so I was eager to compare the more powerful Twin in field use. 

Airing down takes less than a minute per tire with the E-Z deflator, which unscrews and captures the tire’s valve core, allowing a much greater volume of air to exit the valve stem, and gives you precise control with its sliding actuator. The only faster way I know to air down four tires is with a full set of the superb set-and-forget CB Developments Mil-Spec automatic deflators—but that full set will cost you $400, versus $40 for the ARB unit. An E-Z choice, if you will.

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Regarding portable 12V compressors, as with so many other products it’s been my experience that you get what you pay for. The $30 units that plug into a cigarette lighter simply won’t cut it for field use. I know people who’ve been happy with the ubiquitous Masterflow MT50 and its variations, which are available for less than $100; these clip directly to the battery, meaning they can draw more amperage, but they are still achingly slow, and I can recall at least three failures related to me by users. Simply put, if you’re going to go the pro route for airing down (and repairing) tires, you need a pro-level compressor. You do not want to get caught after a section of soft sand with all your tires at 14 psi, no way to inflate them, and 30 miles of rocks ahead. (Especially when it's been six days since you've seen another human.)

Ignore the psi rating—virtually any pump will produce more than enough theoretical pressure. It’s the cfm (cubic feet per minute) rating and duty cycle you need to evaluate. The cfm is self-explanatory. Duty cycle refers to how long the unit can run before it needs to shut down and cool off. A 25-percent duty cycle means the pump can run for 15 minutes out of an hour. It’s easy to see the relationship: A high cfm rating means little if the duty cycle is poor, and a 100-percent duty cycle means little if the cfm rating is below standard. Furthermore, some compressors display an impressive cfm rating at zero psi, but will fall off significantly with higher pressures. Look for factory specs that list both. 

The Australian-built ARB Twin boasts a 100-percent duty cycle, produces 6.16 cfm at zero psi and an impressive 4.68 cfm at 29 psi. How does this relate to the real world? Back on the Birdsville Developmental Road to air up, I hooked up the Twin’s leads to our Land Cruiser’s battery, flipped the rocker switch, connected the chuck to the first tire (still at 22 psi), settled back on my heels to wait a couple minutes, and, er, what? The tire seemed to rise awfully quickly. I disconnected and checked the pressure: 42 psi. I was only aiming for 38 . . . 

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I bled a bit out and moved to the other three tires. I didn’t set a watch to any of them, but it certainly took no more than a minute per tire to reinflate from 22 psi to 38. That rivals my benchmark for powerful compressors, the Extreme Outback ExtremeAir Magnum. And the ARB doesn't have a single "Extreme" in its name.

As a reliable and durable tool for remote use it would be hard to imagine a better configuration than the ARB Twin, given the extensive redundancy: Two all-ball-bearing motors, two cylinders, two inline fuses, and internal thermal protection for each motor. Twin air filters are washable sintered bronze, not paper. It’s highly moisture and dust resistant (the cooling fan is actually sealed to IP55 specs); the cylinder bores are hard anodized and the piston seals are Teflon-impregnated carbon fiber. In addition, the portable kit incorporates a four-liter aluminum air tank, which enables the system to run most air tools (it’s regulated to 150 psi). For the distinctly premium price, I wish the kit came with the ARB inflator that incorporates a dial gauge, rather than the simple clip-on chuck that is standard. But the waterproof case is strong, and the organizer pockets keep hoses and accessories neat—an underappreciated feature on expeditions where entropy nudges things toward clutter. The battery clamps are sturdy, the inline fuses easy to access if necessary, and there's a solidly mounted quick-release fitting for the air line next to the (lighted) power switch. You’ll know you’re dealing with a substantial piece of equipment when you pick it up—the whole package weighs 33 pounds, about as much as a Hi-Lift jack. The compressor alone weighs 19.4. 

If you prefer a built-in compressor (I normally do, but we haven’t yet decided on the final configuration in the Troopy), the air filters of the Twin can be relocated, rendering the entire unit submersible. ARB was not messing around when they designed this compressor.

The Twin is a significant investment ($830 for the kit; $520 for the compressor alone). But consider these two facts: 1) As stressed above, varying your tires’ pressures to suit conditions will do more than anything else to enhance your vehicle’s off-pavement prowess, your comfort, and the condition of the trail, and 2) Tire failure is by a significant margin the number one reason for breakdowns in the bush. With a high-quality compressor such as the ARB Twin you have both scenarios covered with professional-level ease.