December 11, 2019
It’s human nature to modify stuff. From the day the first Paleolithic tinkerer discovered that attaching a wood handle to his stone axe hugely improved its efficiency, we’ve strived for ways to make our tools work better.
The logical modern analogy to that axe is a handgun, and if you’ve ever googled “1911 accessories,” you know how easy it is to spend three times the cost of your Colt on modifications guaranteed to make it “better.”
But modifications can go too far. Is a defensive handgun really “better” if it can fire a 2-inch group at 50 yards at the expense of 100 percent reliable function? The same is true of the four-wheel-drive vehicles we use to explore the backcountry. Rare is the buyer who gets a new truck, tosses in some camping gear, and goes exploring.
Just as with the pistol, however, there are modifications that genuinely improve a vehicle and those that can compromise reliability, safety and other desirable traits, such as fuel economy. And just as a handgun failure at the range has lighter consequences than one in a defensive situation, so a vehicle failure on a weekend hunting trip is much easier to deal with than one that happens on the Dempster Highway or the Canning Stock Route.
Tires/Wheels: Think Conservatively
Let’s start with wheels and tires, the most visible and most common aftermarket purchase—and the most fraught. Everyone loves the look of big, aggressive tires, and they will gain you a bit of ground clearance and, in certain situations, better traction. A large tire will climb a rock ledge that might defeat a smaller tire.
However, those few advantages come with significant cost. As you would expect, larger (and/or wider) tires are also heavier. Switch from a 31x10.50 to a 33x12.50, a pretty modest increase, and you’ll gain about 13 pounds per tire and significantly increase the rotational inertia due to both the weight and the added diameter.
As a result, braking distances will increase measurably and pads will wear out more quickly. Fuel economy and acceleration will suffer. Suspension and steering components have to work harder, and larger, heavier tires put much more stress on driveline components: axles, differentials, CV joints, and the transmission.
They will also negatively affect your gearing, especially in low range. You can compensate by installing lower-ratio (i.e., higher numerical) differential gears, but the only way to do so without a complete axle swap necessitates a smaller, weaker pinion gear, compounding the potential for wear or outright failure.
Need more convincing? Remember that Africa and Australia were conquered by Land Rovers and Land Cruisers wearing skinny bias-ply tires we would laugh at today. I’ve never driven a vehicle on either continent with tires larger than 32 inches in diameter or with tread wider than 9 inches—and that includes terrain ranging from the black-cotton-soil mud in Tanzania to the dunes in the Simpson Desert. Unless you’re building a dedicated rock-crawling machine with a bunch of other modifications, think conservatively on tires. Did I mention you’ll save money as well?
Along those lines, if you’re also considering fancy aftermarket alloy wheels, stay away from the giant-diameter rims that force you to mount tires with three-inch high sidewalls. A four-wheel-drive tire should have a generous sidewall to protect the rim from trail damage and to allow you to air down for better traction and flotation. Note that Jeep eschewed fashion and stuck with 17-inch rims on the new Wrangler Rubicon—a smart choice. On a related note, avoid using wheel spacers to increase track width. They put significant added stress on wheel bearings.
The suspension is another popular component to modify, and in this case judicious changes can achieve benefits as long as you don’t go overboard with lifts. Heavier-duty springs can compensate for a full load of camping gear (or a camper) to maintain a level ride height, although you should still stay within the manufacturer’s recommended GVWR. A mild lift of a couple inches or so can usefully increase ground clearance without drastically affecting handling or fuel economy. Go beyond that and driveline components will begin to suffer; front axles of an IFS vehicle especially will be running at angles they weren’t designed for, causing premature wear on CV joints and boots.
Factory shock absorbers are getting better, and a few vehicles, such as Chevy’s Colorado ZR2, boast truly superior units, but on many other models, aftermarket shocks can greatly improve ride and handling without compromising reliability—a win-win result. Forum debates go on for weeks on the relative merits of high-pressure monotube versus low-pressure twin-tube shocks; in truth, both work well when properly designed. If you can afford a true bypass shock, such as ARB’s superb BP51, you’ll realize the ultimate combination of ride comfort, control, and adjustability. A bypass shock allows compliance over small bumps and washboard while retaining firmness for bigger hits. One suggestion: Stay away from pseudo race shocks that employ all-metal heym joints at the eyelets. Heim joints sharpen handling response a bit, but can wear quickly and loosen. Standard rubber or polyurethane bushings are far better for reliable backcountry use.
Feel the Power
Modern engines produce power we wouldn’t have dreamed of in the dark days of the late 1970s, but for some people, plenty of power is never quite enough, thus the still-vibrant market for “performance” add-ons. One of the most common is a replacement air intake system employing a low-restriction filter. Superlative claims are made for some of these, frequently derived from dynamometer testing, which can bear little resemblance to a real-world installation.
However, even if there are modest gains to be had, the air filters in these systems are invariably smaller than the factory units and situated in the open inside the engine compartment. You get a filter that doesn’t last as long between replacements or cleaning and is far less resistant to water intrusion than a factory intake, which is usually routed through the fender where it also draws in cooler, denser air, which is better for making power.
To Winch or Not to Winch?
A winch is high on the list of must-have accessories for many owners. But is it really a must-have? To be sure, a winch is the ultimate recovery tool and in certain situations will work when no other technique can, especially if you travel solo. And a winch has no effect on reliability. But a high-quality winch is expensive, and you’ll spend twice that mounting it on a suitable, frame-mounted bumper, installing synthetic line, assembling a properly rated recovery kit, and possibly modifying the front suspension. A winch recovery without doubt has the most potential for disaster if not accomplished correctly. You’d be surprised at the boggings you can free yourself from by being patient, airing down your tires, employing a shovel, and deploying a set of MaxTrax.
No. 1 on my list is a dual-battery system, which will furnish auxiliary power for a 12V fridge (this is No. 1 on my “don’t really need it but gotta have it” list!) and will ensure you always have starting power, even if one battery goes dead.
Next is a high-volume air compressor and comprehensive tire-repair kit. With just those two items you will have insulated yourself from most of the breakdowns likely to occur in the backcountry. Not fashionable, perhaps, but practical.
On the issue of safety, I’m a firm believer in bright lighting. Expedition wisdom says you should never, ever drive at night in developing- world countries, yet you almost always wind up doing so. While modern headlamps are an order of magnitude beyond those available 20 years ago, an additional set of high-quality LED driving lamps will significantly extend their reach. One night drive dodging kangaroos in the Australian Outback will convince you there’s no such thing as too much light.
So go ahead and mount those awesome-looking driving lamps; that’s one expedition fashion accessory that might just save your expedition.
Editor’s Note: This column is adapted from an article that first appeared in Wheels Afield, a publication dedicated to overlanding adventure. Check newsstands for the Fall 2019 issue.