[This post is a long one, so you may want to read some and return later. I do not follow the convention of breaking it up into its components, since each of those components interweave with each other to some degree. When the overall topic is finding traction, I’d just as soon publish an article that can serve as a reference, than shotgun the thing just so I can get more web traffic, with the hope that you will consider subsidizing my lunacy. (That comes later, after I’ve established my empire. But don’t worry, I won’t be sending in Brownshirts or anything, for intimidation. They’ll be more like Desert Sage-Shirts, or possibly Taupeshirts… Camo has been SO overdone!) Thus if you have an interest in this traction topic, you can saw your way through. And if you don’t care to infect yourself with it, you won’t be subjected by its different parts for weeks.]
A frequent question I come across among campers in relatively small camping vehicles is “Do I need four-wheel drive?” If you’ve already been camping for awhile and have established the types of places you prefer, the answer is already apparent either way. If you are either an armchair camper planning to get out there someday, or already camp but want to expand the types of places that you drive through or to, the answer can be more elusive.
I’ve been working on this particular topic for well over a year, and the end result is markedly different than the start. I’ve dumped it and started over a couple of times in an attempt to get down to the nitty gritty of it. It started out as a review of all the different types of 4×4 driveline systems as well as tire types and their applicability to different terrains. I found that epic type of presentation to be more overwhelming and boring than helpful. So if you think this article is bad, you should have read its predecessor. While I consider it essential to understand certain basics of how your vehicle reacts to different terrain and how this affects traction, I’ve come to think that presenting a heroically encyclopedic range of facts won’t help my typical reader answer the core question of “Do I need 4WD?” So, 4×4 hardware geekoids and other off-roading enthusiasts may find precious little satisfaction in this post, along with an abundance of caution.
That’s because your typical bucks-down small-vehicle camper or camperette is in a different arena of needs than either of the two primary categories of off-road travelers: 4×4 off-road enthusiasts and overlanders.
Pigeonholing the Mobile Lifestyle.
4×4 off-road enthusiasts attempt to make impossible terrain possible, mainly by throwing hardware and throttle at it. They typically live at home and go out on weekends with like-minded friends, and the pack of them find the toughest terrain available in order to face the challenge of it. Usually, their vehicles are heavily modified in order to accomplish this, both to succeed against the challenge and to get unstuck again when the difficult terrain wins the battle. There is no destination per se – the goal is to return the vehicle home under its own power, and to address any equipment problems in time for the next off-roading adventure. I consider that the attractions of it are the challenge, the adrenaline, and the difficult physicality more than the vehicles themselves. There is a certain satisfaction in making one’s vehicle succeed in traversing a difficult path, and experiencing the physical sensations of how it operates at the edges of what it can accomplish, no matter what that level may be. I tend to think of it as armchair mountain climbing, with a cupholder. It’s a hobby in the sense that the driving part is a passive activity, but it becomes more like a sport when the thing gets stuck and it’s up to you to get out and do whatever it takes to free it. At that point is when you discover your basic fitness level and perhaps your competency in improvising a solution with the recovery equipment you’ve collected.
There is a wide range of attitudes in approaching this hobby, ranging from being a fun and challenging shared activity with friends, to individuals obviously working out some sort of personal issues on YouTube. Among the latter, broken driveline components and dented panels are badges of honor, and the money spent is of no particular concern as long as they can eventually go back out and get their thrill fix on camera again. It’s a troubled love they have for their vehicles. Much like abusive boyfriends who deserve restraining orders against them, they loudly profess admiration and pride in their vehicles, adding the next new adornment, then they beat the crap out of them. They hold the broken parts out for someone’s camera. That’s a chosen driving style, not a necessity to succeed. Your average hobbyist is out there simply to have fun, hopefully without getting irretrievably stuck.
The goal of overlanders is to get from Point A to distant Point B safely, via whatever network of roads or trails will allow that. In the rough, they must stick to established trails, so although they view the trips as exploration and adventure, the exploration aspect is more of a “new to you” thing, which is perfectly valid. Just because someone or many someones have been that way before doesn’t mean that it won’t be fun and challenging for you. Of necessity, they take whatever route is called for, and must face whatever impediments it presents. Though the priority is to arrive at Point B safely – with the vehicle still fully operational – the emphasis is not so much arriving at the final destination. The emphasis is on the enjoyment and challenges of the journey itself, as well as the overnight camping with friends along the way. It’s the experiences. Tent-based camping dominates in this group, which allows the use of smaller, lighter and more agile vehicles. A few sleep in the vehicle under a truck bed shell or canopy, though this use of space tends to put a big dent in the storage of provisions and equipment, making long distances between waypoints impractical. Lightweight pop-up truck campers are used successfully too, though the added weight, larger profile and rise in center of gravity compromise the vehicle’s off-roading ability.
According to Overland Journal, “Overlanding describes self-reliant adventure travel to remote destinations where the journey is the primary goal.” Overlanders consider the journey itself to be the purpose. It can also be the interactions with other cultures. Overlanders typically travel in small groups, both to enjoy the campfire camaraderie and to help in negotiating obstacles and extricating stuck vehicles. As long as the trip lasts (which can be a few days or many months), they camp out of or in their vehicles, then go home to review the experience, plan future trips, and address any equipment issues that surfaced along the way. Solo trips are occasionally done, which makes satellite-based phones or other emergency communicators essential, along with off-road GPS navigation devices. There is much more of a safety orientation among overlanders because of the distances involved and the lack of even basic facilities and services within reach. Driveline breakage can mean getting stranded in isolated spots. Improper use of recovery equipment (as is taught on some popular mobile lifestyle websites) can and has resulted in life-changing injury in the middle of nowhere. Since that’s bad, a good percentage of overlanders take their chosen activity more seriously than just following a dirt road, camping, and calling that overlanding. They research to gather information, study or take classes, and practice. Most overlanders will carry a selection of spare parts, tools, and a few will even pack welding equipment. That last one might be more of a statement about vehicle condition or suitability to task, or perhaps driving style, but since overlanding is commonly a group activity and the roads frequently stress the vehicles, this can also be done “for the group”.
Self-reliance is a high virtue among overlanders. It has to be. The need to get to Point B prompts most overlanders to learn how to drive off-road without breaking their vehicle’s mechanicals in the first place, an emphasis which is harder to find among 4×4 off-road enthusiasts. There’s less bonsai to it, and more figuring out how to best negotiate difficult spots.
Small-vehicle campers tend to have a radically different situation going for them, while they share some operational traits with overlanders. While most will have a home to return to and an adequate if not generous income to support their hobby, many will be full-timers with no residence and little income. The emphasis of this post is toward this latter group, since most travel solo and will have very limited means to upgrade equipment. “Run whatcha brung” is the dominant theme, and most will operate with vehicle-based camping, which tends to point towards larger and more cargo-capable trucks and vans. While that’s very good for living out of, it inherently compromises a vehicle’s athletic abilities off-pavement, as does overloading a smaller one. The constant use of developed campsites is a rarity, since even an amenity-free $10 campsite means $3,650 dollars a year in costs. Satellite communications equipment for emergencies can be helpful, but assumes that A) there is someone to contact for help and B) the intended rescuer is not 2,000 miles away, which greatly complicates making local rescue arrangements in a timely way. Satellite phones to contact a local tow service directly are expensive, and require monthly plans which are not cheap, either. In short, there is always a technical way out of any difficulty, though it may not be pretty or inexpensive.
So, typically alone and with a well-used vehicle at or very close to stock, such campers must be more cautious about their approach to traveling off-road to find remote campsites. You may find that your road or RV towing insurance does not cover you when on unmaintained roads. You can still get help, but the costs are typically bank-bruisers. But, travel you must. In order to stay in comfortable temperatures, altitude changes are necessary. So while campers may have an ultimate Point B in mind as the season progresses, the emphasis is on Point A1, Point A2 etc. as camping waypoints along the very slow journey. Over time, it’s a big loop and for some, a very big loop.
Finding adequate traction while driving along unpaved roads is usually not a problem. Now and then, it is, and when it is, it’s suddenly a big deal, ranging from hours of struggle and delay, to bodily risk. This post is partially meant to combat the perception that vehicles are mysterious black boxes understood only by engineers and off-roading experts, leaving you helpless to understand the basic dynamics at play when traction proves to be poor. If you can reason out exactly why your vehicle has lost traction in a given situation, you’re not left helpless and hopeless. Recognizing a risky situation for your specific vehicle is the first step in knowing whether to proceed, or back down and look for another interesting trail. You can afford to throw caution to the wind if there’s another vehicle around to extricate you with a tow strap, snap strap or winch. If there isn’t, the decision-making process needs to take a markedly different tack. If you’re the type that just goes until the vehicle stops, whose sole solution to failing traction is to floor the gas pedal, or you don’t want to bother with figuring out what happened underneath you to get you stuck, the answer to your 4WD question is: no, you are probably better off without it. Just stick to easy campsites with cellphone service, and avoid having to drive on muddy trails. That’s not condescension, that’s just practical advice to ensure your safety. If you already have 4WD, engage it only to reverse out of the situation and go back to easier terrain. With a few exceptions, that’s what I do.
Now as I’ve pointed out in the past, the Mighty Furd has some inherent mechanical constraints that greatly affect its off-road abilities. As a 3/4-ton full-size truck with a lightweight pop-up camper on the back, it can reach many remote campsites. But, it’s distance between the front and rear wheels, front and rear overhang, width, sheer weight and limited fuel range keep it from doing what overlanders do on the roads and trails that they ordinarily choose. Recovery equipment that can handle its 10,000-pound bulk is limited and quite expensive. Some capability issues can be addressed with aftermarket parts, but nary a one of them will be implemented unless one of those trail problems rears its ugly head while I’m on tour in the very mild trail situations that I limit myself to. That’s pretty unlikely. Being a dedicated cheapskate tends to lower one’s off-roading horizons, as does being chicken-hearted. It’s a combination that works well for me overall, however. Some kinds of adventure are not always good things.
My Goals May Not be Yours.
After all, my goal for camping in the Intrepid is not to traverse long and desolate stretches of hazard-laden trails, overland style. To do that safely requires adding much more specialized equipment than I can afford. Although genuine overlanders generally are crazy enough to attempt their explorations solo, they do so properly equipped to deal with trouble. Their goal is challenge and adventure, not suicide.
All I want to be able to do is to camp in locations that are just challenging enough to induce 90% of the conventional campers who approach them to turn back and look for something easier. Out in the Great Southwest, solitude does not have to require serious distances from supply sources or towns. All it takes is the willingness to fully use what you’ve got, combined with a decent ability to recognize terrain and surfaces that may go beyond your vehicle’s unique capabilities – or your own. This is where the question of needing four-wheel drive tends to get fuzzy. Tire placement and driving technique count for much, sometimes more than the presence of two more powered driving wheels. Frankly, I tend to bow out early, and when the inevitable urban-style random mechanical failures occur, I should normally be within my modified Evelo Aurora e-bike’s striking range to get either into cellular phone range, or to the nearest town. Things like a failed starter or a sudden coolant loss can happen anywhere, any time. There’s no point in accelerating natural failures or creating new ones by punishing the vehicle, however. That’s the gleeful task of 4×4 off-road enthusiasts.
But are you going to need four-wheel drive? That depends on you, where you want to go, and in what. Most campers can get along just fine with a 2WD vehicle, because many if not most fire access roads and trails are pretty passable in dry weather. If you’re planning on carrying a truck camper or towing a trailer into remote areas where roads are not maintained, 4WD makes a good backup for escape when 2WD mode is struggling or has gotten you stuck. The core of this is to use 4WD as a means of vehicle recovery rather than as a way to get yourself into more serious trouble than you otherwise would have with 2WD. If you are traveling solo and bouncing against the limits of what your vehicle can do (regardless of drivetrain type), it would be prudent to greatly ramp up both recovery equipment and emergency communications equipment, along with your familiarity with the proper/safe operation of each. There are numerous places in the Southwest that you’re just not going to be able to walk out of, or call for help from using a cellphone.
Where your comfort level with risk is, and how you decide to approach a situation like that is up to you, but I can tell you that a careless decision here can cost more than money, and the rent comes due a lot more quickly with age, ailments or injuries, heat, and desiccating air. How inaccurate your perception about a situation is does not affect the outcome so much as the degree of surprise as the reality of the situation finally sinks in. Better to accurately recognize and deal with potential risks in your own style, than to get stuck in the seductive Assumption of Invincibility that pervades suburban life and clings to us wherever else we go.
When the Adventure Lifestyle Goes Rogue.
Its not that we should be afraid to have adventures off the beaten path. That’s the fun of it! It’s just that it’s a bad idea to assume that a trail exploration is merely like the long way around to a store, or that the worst penalty for thoughtlessness is inconvenience or an argument with an insurance company. Do you figure you might be in areas where seasonal mud is an issue, or you have a 2WD vehicle and a few of the trails you’re attracted to are rated “Moderately Difficult”, or you’d rather flip a 4WD knob than break out a shovel and cable winch? Or maybe you envision pleasantly developed campgrounds, more fun places and sights than trailblazing, or going around risky circumstances instead of lurching into them. There’s no formula to follow as to whether you need 4WD, and no chart to look at. You pretty much already know whether you should get or avoid 4WD. You’re just waiting for someone else to validate the way you’re leaning. Neither is “better” than the other, but one may be more appropriate for what you want to do.
If you’re planning on pioneering across spans of deep sand or gravel, as can be found in washes and on beaches, 4WD becomes mandatory, along with weight reduction and wide tires. Plus, you must learn how to drive on those surfaces. If you will be in remote areas during a rainy season, you may find yourself temporarily trapped by impassible mud even with 4WD. It pays to keep tabs on weather forecasts and observe the ground when you enter a new area, no matter what your driveline type is. Gravel and rocks with dirt, good. Washes, ruts and silty soil on either flat or hilly ground, bad. You may crave “adventure”, where you impulsively spend a few memorable hours on a muddy trail while throwing rocks, logs and anything else you can find under tires to try to get out. Or you may prefer to plan such that you can wait out the weather in camp, then head out after the track has dried sufficiently. Your choice.
Technicalities aside, the real answer as to whether you need 4WD is: if there is doubt, there is no doubt. Seriously. If you’re planning to transition to mobile living, you can use what you have and just live with its limitations. If it’s a van, so much the better – the 2WD/4WD issue is decided for you, unless you earn beaucoup bucks and can afford a conversion to 4WD. If you don’t have a vehicle suitable for either a truck camper or trailer yet, some introspection is warranted. 4WD costs money, and repairing or rebuilding it costs money. Buy it used from an owner who brags about how well it works and how tough his vehicle is, and it will really cost you money, later. The questions that actually lead to 4WD swirl around the issues of how flexible your travel schedule is, what the limitations of your provisioning choices are for food, water and waste, and the level of serendipity you prefer to operate under. I would mention the terrain you expect to encounter, but one usually doesn’t know that in enough detail to distinguish drivetrain suitability. After all, you’re exploring. You discover that when you get there. So basically, if you have any doubts about whether you can go where you want and do what you want with 2WD, there is no doubt that you should give 4WD more than a passing consideration. Same if you’re not familiar with the terrain you’ll be encountering, or the weather conditions that typically prevail there. This is why overlanders stick exclusively with 4WD. But since you’re a camper looking for a pleasant, secluded site, you have more flexibility about where you will go and how you will get there.
Trails that are connectors often have a class of difficulty assigned to them, which is a comparative rarity. This rating system varies quite a bit, and is based on the assessment of members the organization that most often uses the trail. Some use “Easy-Moderate-Difficult”, while others use a numbering system from 1-5 or 1-10, which makes knowing the entire range used imperative. Figuring out which level may be passable by your own vehicle can get a bit fuzzy. My F-250 has just 8″ of clearance at the front differential and at two tie points on the front axle, with 11″ at the running boards, meaning that I might be able to skirt some “too large” rocks with careful placement – which the trail width may or may not accommodate. You find out when you get there. The 1-10 scale is more popular. Trail ratings and trying to figure out suitability for a stock vehicle is best handled in another post, since this one is about finding traction. Just for reference though, the Mighty Furd is best limited to Easy trails, or 1 & 2 on a 1-5-scale rating, or up to 4 on a 1-10 scale. Note that taking such trails solo is recommended against by just about every club on the planet, and for good reason.
It’s so easy to get hopped up over “off-roading” that one can forget the goal. The goal for off-roading campers here is not to get stuck, break parts, or prove manhood by flailing a helpless machine. Neither is it to provision for epic explorations in 600-mile refueling stretches across the Transvaal, between the Vaal and Limpopo rivers. That’s for overlanders, who do not live in their vehicles for any longer than the duration of the trip. The camper’s goal is simple. It’s to find a beautiful or even inspiring place to set up camp, a place which is both sparsely occupied and accessible with whatever vehicle you’ve shoehorned yourself into. You adapt your camping expectations to the machinery you already have, and if you don’t have anything yet, you adapt your camping equipment choices to your camping expectations, at least until your savings account tragically passes away during the build process.
What You Choose, to Face What’s Out There.
Forget the exciting off-roading mods and equipment for a moment. If all you’ve got is you and your stock vehicle, it pays to take a look at what you have right now, and make the best of it until you win the lottery that you never remember to buy a ticket for, and wouldn’t win if you did. Sometimes, it’s easiest to start by example, rather than by dry principles. So, let’s look at the Mighty Furd in more excruciating detail, in order to learn some basics. Its 4×4 chassis design intent is to deliver heavy cargo (up to 2,460 pounds) from paved streets to rough, marginal-traction construction areas. Its diesel engine powertrain swings it toward a mix of more demanding hauling and towing conditions (12,500 pounds for a bumper pull trailer & 16,000 pounds for a fifth-wheel). It’s a good example because this combination does what it’s designed for very well, yet also makes it a relatively poor choice for off-road exploring, despite its four-wheel drive.
Why? There are several factors going here in the Great Southwest:
- Most off-road trails not created solely for use by utility service trucks are narrow, and that manifests itself in everything from very tough, paint-scraping bushes to narrow passages lined with rock. Most of these trails were created by Jeeps, and some are best used only by ATVs. The big Ford’s sheer physical width works against it here. It’s not that it can’t force its way, but that’s usually more a size-of-your-wallet issue for repairing all the damage that would result.
- Abrupt ascents and descents. The farther apart you place the front and rear wheels, the easier it is to ground out the middle of the chassis going over a rise. I might have the same rated ground clearance as someone else’s little stock 4×4, but only one of us is likely to be able to drive over a large berm without getting hung up, and it probably won’t be me. Bigger vehicles also tend to have more front and rear overhang, which makes it easier to ground out during the approach toward or departure from an obstacle. Grounding out some portion of the chassis isn’t the real problem. It’s the exposed and expensive hardware that’s attached to the chassis. Gore that or wipe it off, and you’re going to have big costly problems, and fast.
- Deep dust, sand, gravel, and mud. Sometimes weight can work for you, as in “momentum”. A rolling 10,000 pounds is a lot of momentum to ease you through or over surfaces that you would normally get bogged down in. With crawling situations however, weight usually works against you, since each wheel is driven deeper into the troubled surface. And if you get stuck, it may well take a heavy vehicle equipped with one hell of a winch to get you out. Ramping up speed to apply all that momentum sometimes works, but sometimes works against you. Charging down a bank into any of these, particularly mud or a water crossing, can instantly erase the extra momentum, make the front end dig deeper into the surface than it otherwise would, and potentially cause all manner of havoc under the hood.
- Water crossings. All 4WD vehicles intended for off-road work will specify a maximum water depth in their manuals which should not be exceeded, and that value varies for each vehicle. It should be taken seriously for stock vehicles. The Mighty Furd has a rated depth of just 14 inches, which is the distance from the ground up to the bottom of the front hubs. This is because its fancy optional remote-control hubs have a mechanism that is actuated by vacuum, so submerging them under water would tend to suck water into the hubs. Not a good thing. Even apart from that, driveline devices generate heat, so they all have breathers which are open to the air and prevent hot air pressure from blowing lubricant past various seals. The stock Super Duty’s breathers are on top of each device, but don’t extend much above it. So, submerging the axles, transmission, or transfer case underwater will mix water with lubricants or hydraulic fluid, ending their functionality in short order if I emerge and keep going. Extending the breathers upward would allow deeper water crossings, but there’s not much that can be done with those front vacuum-operated hubs. Replacing them with fully-manual ones is impractical to do. Not going to happen. Whenever you see a vehicle plodding along in deep water up to the top of its tires, you’re looking at a vehicle that’s (hopefully) been specially modified to be able to do that.
- Eroded surfaces. Crossing dry washes is a combination of items 2 & 3 above, but it’s common to find that trails on slopes have become water channels. The water finds the lower side and cuts a deep groove into the dirt. This can become a sizable little canyon pretty quickly, creating considerable side-tilt when not threatening tire sidewalls, shock mounts and axles with impromptu disassembly. The eroded area usually offers poor traction as well, making steep climbs more interesting. Placing your tires in existing ruts is often a problem, when the rut shaping prevents full contact of your tread to the surface. These are things to evaluate before crawling along ruts and washouts in a heavy, stock vehicle, particularly in one which has a wider stance than the vehicles that originally created the ruts. Tire treads need full ground contact, and that ground needs to provide enough traction to get past.
- The diesel engine’s ample torque. That translates to its eagerness to pour massive amounts of power to the tires even at very low engine speeds, like when crawling up a rocky slope. Why would that be bad off-road? Isn’t more power and responsiveness a good thing? Answer: only if it’s highly controllable, so you can tip in only what is needed. Beyond a certain mild rate, wheelspin off-road is counterproductive. In most conditions, a rapidly spinning tire has significantly less traction than one which is not spinning. It’s lost its bite. Spinning helps tires dig holes and get the vehicle more stuck. The Ford’s 6.4-liter diesel, though whimpy by modern standards, provides no clues as it just keeps churning away at the same speed no matter what the tires are or aren’t doing. If the ground is moving past, you’re okay. If it isn’t, you’re apparently stuck. On slippery ground, this trait makes getting stuck easier because the touchy-feely aspect of minimal wheelspin simply isn’t there to signal you. Shifting into 4WD-Low greatly magnifies the problem, and the throttle becomes inordinately touchy. Wheelspin on clean, dry pavement is no problem at all there. You may be able to pull tree stumps with it (as I have), but maintaining good traction on bad surfaces requires fine power control and a sensory signal that simply isn’t there. Heck fire, you can’t even detect when a tire on it goes flat. It’s tough to modulate power when so much is available at crawl speeds, making getting unstuck more difficult. It’s like trying to crack an egg in a pan with a 32oz hammer. I can’t imagine the depth of this fine-control issue on modern pickup diesels, which now have half-again as much torque as mine. It’s a superb trait when you have traction, and a headache when you don’t. Thankfully, according to the owner’s manual, the Furdmobile has one odd option with its automatic trans: put it in 3rd. It stays locked in 3rd gear from a standing start, making for a relatively soggy, more controllable launch. I just found out about it and will have to try it out, but that must be a little tough on the torque converter, I would think. Those are expensive, too.
- Lowering tire air pressures in order to improve traction or smooth the ride is not as effective on the F-250 as on lighter vehicles due to the Ford’s E-rated tires. The thick sidewalls generate more heat and so can’t be allowed to bulge the same amount. Though the ride smooths considerably, it’s still no pillow ride. Airing back up takes 30 minutes with a mid-speed pump, since inflation pressures are much higher than D- or C-rated tires. Deciding whether to air down tires or not isn’t a consequence-free decision with such a vehicle.
- Surfaces that induce pronounced suspension twist. Called articulation, this can be created by dropping one tire into a deep hole while doing the same with its diagonally opposite wheel. Imagine crossing over a high berm at a 45-degree angle. Each axle includes one tire with exceptionally little weight on it, while the opposite tire on that same axle is carrying about half the vehicle’s entire weight. This is a losing proposition from the get-go. Most stock 4×4 and 2WD vehicles will deliver power only to the tires hanging uselessly in midair. Throw enough money at them, and they can lock up all four wheels (or both wheels for 2WD vehicles) at the same rotational speed, which puts power to the overloaded tires as well. That’s a lot better, but keep in mind that the vehicle is now depending on half the rubber contact with the ground that it normally does. The better the vehicle’s articulation, the better it can keep all four tires in solid contact with the ground to improve tractive power. Poor articulation can be real issue for stiffly-sprung vehicles like the F-250, because its ability to carry cargo conflicts with its need to keep all four tires in contact with the ground no matter what. Its design bias rightly goes toward cargo capability, otherwise you’d have bought an F-150. Those two wheels with all the weight on them are so stiffly sprung that they lift the entire vehicle up higher, leaving the two “unused” tires with so little weight on them that if they aren’t dangling in the air, they may as well be. Poor articulation is not quite as much of an issue for half-ton trucks, and can potentially be good in SUVs if the basic suspension design is deliberately biased toward it. Jeep Wranglers now have perhaps the best suspension articulation on the planet, but they also have the least cargo-carrying capability for overland travel. That makes them very popular among off-road enthusiasts, but more of a problem to live with among long-distance overlanders, who often need to pack for long trips.
Point number 8 above introduces the core of what makes a 3/4-ton or 1-ton truck a comparatively poor choice for off-road exploration, but if a lot of weight must be carried, there isn’t much of a choice of being able to scale down to a softly-sprung version. Let me get redundant. Why softer springs make a difference is this: in that crossing-the-berm scenario, the two on-peak, overloaded wheels can move up a greater distance before they start to lift the truck, which keeps the whole vehicle closer to the ground, giving the two dangling tires a better chance to reach the dirt and keep some tractive force going. For maximum traction on a given slippery surface, all powered tires should ideally be loaded equally. (Oddly, when the Mighty Furd is loaded up with the camper, cargo box and e-bike, weight distribution at each tire is within 100 pounds of each other. It may have a host of other bad traits, but weight distribution isn’t one of them.) The less equal the tire loads get between powered wheels, the less motive traction will be available overall. Going over uneven ground forces unequal tire loads that change constantly. This principle works for both two and four-wheel drive. The Mighty Furd is equipped with a standard limited-slip rear differential, which would normally help by forcing the overloaded rear tire to rotate and power the truck forward. Not for 2008 models like mine, however. Those have a habit of no longer working after maybe 40,000 miles. Oh well.
Let’s get excruciatingly boring. If you can imagine a 1,500-pound load resting upon one tire on wet grass, then you can also imagine that putting rotational power to it is going to go a lot better if we keep the full 1,500-pound load on it, pressing the tire down with the full weight to be moved forward. Lifting it up so that it now presses down with just 400 pounds of pressure to the ground is going to be problematic, when the weight to be moved forward remains the same 1,500 pounds. Cut that tractive pressure further, to just 50 pounds, and it will spin in vain, unable to push the load forward at all. Given the typical “open” differential, the driveline will push its power to whatever wheels lack traction, limiting tractive push to that of the least effective tires. Serious modern 4WD drivelines can overcome this trait by several methods, but the Mighty Furd’s system, serious in its day, is now old school and way behind in what terrain it can handle. It can certainly be upgraded of course, but there’s that money thing again. So, it helps to recognize what’s slipping, where, and why, and just work around it as best one can.
On a 2WD truck or van, it would be nice to emulate the old VW Beetle’s 35/65% front/rear weight distribution, putting as much of the vehicle’s bulk as possible onto the two rear drive wheels. But just the opposite is the reality for pickups. Vans are usually better in this regard because of the added weight of the enclosed body. With an empty bed, most of a pickup truck’s weight rests on the front wheels, which are not powered. This is especially true of the unladen Mighty Furd when 2WD is selected, because of the extra weight created by its diesel engine and front drive axle. A truck bed by itself is no feather, but it’s much lighter than enclosed body structure. Left in 2WD mode, the Super Duty, without the camper in place, is more helpless than most other vehicles are on low-traction surfaces because its physics are working against it: add more total bulk with the heavier engine, but reduce the tractive ability to power forward by adding all that extra weight to unpowered wheels. This gives the driven tires in back more to shove forward, but without any increase in friction to do it with. If there’s weight to be moved, the more of it that rests on driven tires, the better. That’s what made the old Beetle so good in snow, and what makes most front-wheel drive cars just as good, if not better. And that’s why 4WD seems like the instant fix – the entire weight of the vehicle rests on driven wheels! Unstoppable, right?
You guessed right – I’m preparing you for a bummer. Yup, 4WD is superior overall, but it’s not unstoppable, of course. Tires have traction limits on ice and in mud, as you know, but that’s not what I’m referring to. That “even pressure on all powered tires” thing still applies. It’s the stiff springs and lack of articulation issue, which forces downward pressures to be uneven when bumps are encountered. Ideally, a powered tire should not have to move forward any more weight than what is directly bearing down on it. That’s not always the case though, since although the vehicle’s total mass stays the same, the individual tires underneath have to cope with wildly varying loads and traction levels. Off-road on uneven terrain, 4WD can quickly run into traction problems once the loads on tires start becoming uneven. Without a more sophisticated 4WD system, the highly-loaded tire isn’t the one that gets the power, so its better traction gives the vehicle no advantage. It can’t push forward any harder than its struggling brother on the other side of the axle. SUVs get the fancy, effective 4WD systems. Historically, with one notable exception I know of, pickup trucks do not. That one takes more of a brute force approach without any sophistication, but it works.
The Mysteries of the Locking Differential.
Vans are limited to 2WD, though a few can be converted to 4WD at heart-stopping expense. A limited-slip or “locking” axle on rear-wheel drive vans is often available but seldom ordered. Adding an aftermarket differential can certainly be done, but it’s far from cheap. The bane of campers in vans is long, flat tracks of muddy trail, where the downward loads on the drive tires don’t vary much, as a result. I’ve always lamented the tendency of standard open differentials to direct all the drive power to the tire with the least traction, referring to it as “1WD”. In my experience with cars though, that’s not really accurate. The open differential will inherently try to rotate each wheel with the same force – based on the one with the worst traction. Whatever tractive power the worst tire has, say, generating a forward push force of 100 pounds, the better-gripping tire on the other side of that axle will match it. Should the bad tire briefly hit a good patch and pop up to 200 pounds of push, the other tire will instantly match that, too. So although 400 pounds of tractive power to push a 6,000-pound van through deep mud may be pathetic, the moral here is that both tires are always pushing equally hard, and just how hard is always based on the tire with the worst traction.
A locking or limited-slip differential is often touted as the magic fix to get through mud with a 2WD vehicle like a van, since this type of differential may not be able to help the “bad” tire find traction, but does make sure that the “good” tire gets all the power it can handle. Thanks to the better differential, the more tractive power the grippy tire has, the more of a shove forward the van gets. Trouble is, it’s not quite the nirvana it’s often painted to be in your typical mud flats situation, where the Medusa of articulation isn’t rearing its ugly heads. Both drive tires are carrying very comparable loads, and both are typically facing the same traction conditions. Same mud, same depth, same loading, comparable grip. In this common case, the boast of “twice the traction now that both tires are getting power” is nowhere close to reality. A LSD (limited-slip differential) or locking differential only make a difference when one tire has a distinct advantage in traction. That’s not the case in the most common mud scenario, and you have to hope that one tire or the other somehow finds extra traction, perhaps on buried rocks or gravel. If it doesn’t, the big bucks you poured into the new diff fails to make much of a difference in getting you through any better than the original stock open diff. Mechanical LSDs that are in good working condition won’t even bother engaging unless one tire has a decided advantage in traction over the other. LSDs and locking diffs are a very good thing to have in most difficult situations, but churning through level mud (or having both drive wheels on ice) is not one of those situations. Off-road 4×4 enthusiasts are often surprised and annoyed to find that stock vehicles with standard open diffs often climb muddy, messy grades better than their costly dual-locker bretheren, simply because there are no good traction patches on the way up and, unlike locked diffs, open diffs do not create steering problems that lurch the vehicle off into even worse territory.
For the record, my year of truck did offer a Special Offroad Package that included an onboard air compressor for its air shocks and for adjusting tire pressures, bead lock wheels with a tough inner liner to fight punctures, a 15,000 pound-rated Warn winch, front limited-slip diff, and a locking rear diff. Those and other features could be ordered only by law enforcement agencies. Frowny face.
Your Tires and You.
Since tires are our vehicle’s only link to actual traction on the ground, I’ll have to include them as part of this Traction Jackson post as well, but I’ll try to keep it as brief as I reasonably can, which is not real brief. The “proper” tire choice varies wildly with how much you drive on what kind of surfaces, and it does little good to see what others in camp are using and just assume that those will be best for you, too.
Tires represent a host of trade-offs to boost performance on one surface over another. You’re pretty much limited in width choices by your existing wheel rim width. Wider is better on most surfaces, particularly sand (for flotation), but mud tends to throw a wrench in that as a universal fix to everything. I’ve observed that you’re more likely to get through a churned-up, thick gumbo than you are a layer of water over an undisturbed base of slime. Given an aggressive tread, a narrower tire usually faces less resistance in pushing through, and is more likely to burrow down to get to the solid base – if it exists at a reasonable depth. Get what you want, of course, but don’t just assume that laying out big money for wider wheels and tires will take care of everything you might face. Everyone travels to different places, and so may need different priorities, but for a camper/RV, stick with light truck tires instead of falling for any passenger car tire that will fit.
The typical street A/T (all-terrain) tires you buy are okay for most purposes. They last many miles before they wear out, are quiet, and can handle dry trails and wet pavement as well or better than anything else, including sand, where they tend to have decent flotation to stay near the surface. On sand, flotation is a higher priority than traction, since sand is too light and easily thrown to propel the vehicle forward anyway. It’s like trying to get a grip on a deep layer of packing peanuts – they just move out from underneath, and down you go. On pavement, street A/Ts are quiet, give good fuel mileage, and handle well. Once you’re exploring gravel and rock trails however, they can suffer cuts and lose chips out of the tread.
The sidewalls are more vulnerable to punctures from brushing hard against sharp-edged rocks, too. In mud, they are fairly hopeless. The tread immediately clogs and goes out of action, leaving you to churn away with smooth, muddy donuts. Street-type A/T tires are a good first tire choice, and your experiences with them off-road, where you go, should be a pointer as to whether your next set needs to be tougher or have more aggressive treads with chip-resistant rubber. You replace them with something else only if they don’t prove satisfactory where you go.
If you should have traction or durability problems on trails, look at the comparatively small amount of miles that you drive on trails versus pavement, and decide priorities. If you’re occasionally getting flats or are ruining your street A/Ts, the decision to move toward trail-specific tires is fairly easy. You literally can’t afford not to get them. If you’ve had some close scrapes with traction, you may want to decide whether to move to the next most aggressive tires, or back off on your exploration style. Most tire manufacturers make tires more aggressive than street A/Ts. There’s no official separate designation for these. Just look for a more open tread pattern and some mention of off-road suitability. They may not reach as high a wear mileage, and may have less handling stability on pavement. Ideally, the tread design will begin to wrap against the sidewall for better protection, but that’s rare here. Few of these are compounded to specifically resist cuts and chips in their tread from gravel roads. Some are deep snow-rated (with a small snowflake icon molded into the sidewall), and many are not. The very best of the severe snow rated tires, you do not want. Those specialty tires should come off once winter is over, since the soft rubber compounds will quickly wear in warmer temps and be less effective when winter rolls around again.
There’s a step above this as well, also arbitrary, and they are most easily recognized by bigger voids between the tread lugs, and an obvious rubber sidewall wrap. With that protection, better puncture resistance overall, a cut and chip-resistant rubber compound, added sidewall plies with more durable cord, and an even more open tread pattern, such tires are about as trail-worthy as you can get. This class of tire is most often used by serious overlanders for their combination of traction and durability. Many of them may look vaguely like 1960s snow tires and are fine on snow, but they are comparatively awful on ice unless they have been compounded for it. Drawbacks? Compared to street A/Ts, they feel somewhat vague on pavement, dry or wet. If you street drive like Speed Racer, you’ll find yourself backing off a lot. The unsupported, squirming tread lugs and extra sidewall plies can build up more heat at highway speeds, and the treads do not last nearly as long as A/Ts. They usually lack any mileage guarantee. They will tend to clog with mud just like any other tire, but mud ranges from watery broth to thick clay gumbo, and if the mud is thrown off the tread, it will happen a earlier than on other, tamer tires. You’re sacrificing a lot for considerably better grip on most trails. How much are you willing to give up for much better off-road performance? Sand can be their one bad point off-road, but how bad depends on the tread design. In general, open tread designs tend to dig down through deep sand, which is exactly what you don’t want. Better to float on top even if traction is very limited. Some treads are configured to try to trap sand between tread blocks instead of throwing it out of the way, but the aggressive tread makes it awfully easy to start digging toward China if your driving technique is sloppy. Soft, deep sand calls for speed, which grains then can’t move out of the way quite fast enough, and keep the tire afloat where it would normally bog down from vehicle weight. BFG T/A KO2 tires are popular trail tires among hard core overlanders. (B.F. Goodrich, now the Goodrich Company, stopped making tires in 1988 and was bought by Michelin, who makes BFG tires now.) The Cooper Discoverer S/T Maxx is a highly regarded model as well, particularly in Australia. I have a set of the latter on the Mighty Furd, and although I suffered one tread puncture on an unmaintained road last year, the grip has been very effective. The sidewall protection wrap works. My set has 30K miles on it so far, and there looks to be at least another 10K available. Handling when new was a bit spooky when heading into turns on pavement, but the tread wear has now tamed this to street tire levels. (FYI: Besides Goodyear and its subsidiary Kelly Springfield, Cooper and its sub-brands is the only other “major” American-owned tire manufacturer left. Titan is American as well, but not yet on the radar for size. Firestone, General and Uniroyal were snapped up decades ago by foreign majors, though many foreign outfits also manufacture here.)
Mud tires are the last option, useful solely for mud and for impressing your friends with their gnarly appearance. The treads of these have even larger open gaps, in the hope that spinning the tire will more easily throw off the mud and clear the tread for the next bite. Mud can allow a faster wheelspin rate than other surfaces, but its consistency matters, as does its depth to reach a more solid base underneath (if any). Mud tires do perform better in mud than any other tire type, since they stand a better chance of not clogging up. But, they suffer all the faults of trail tires to a greater degree, and then some. Rubber is heavy and some mud tires have plenty of it, so I wouldn’t try to span the Interstate at 70-80 MPH with some of these, personally. They make the most sense if you don’t rack up many miles per year, stick to lower-speed roads, and have to deal with muddy trails a bit too often for your liking. (If you like mud-soaked trails, then you’re a closet 4×4 off-road enthusiast, not a bucks-down camper looking for solitude. Stop reading this and go get a good-paying job to pay for more hardware.) Thing is, if you’re choosing to face conditions that warrant the use of dedicated mud tires, you should also be packing fully competent recovery equipment, and be well-practiced in its safe use. Too, you should not be traveling without a comparable companion vehicle.
Your Priorities May Not be Someone Else’s
Unlike most off-road driving hobbies, off-road camping, like overlanding, places “arriving safely” at the top of the priority list. If you don’t arrive when expected, you’re obviously still out there struggling with who knows what, and if you’re not considering your personal safety as key, your odds of you and your rig arriving intact are questionable at best. If you’re planning to push the envelope of your vehicle’s capabilities (whether 2WD or 4WD), you need to be able to deal with a situational failure, and deal with it in such a way that your physical welfare is not compromised.
Some people choose not to prioritize their physical safety in driving or using recovery equipment, and they have that right. Adventure wouldn’t be adventure without risk. It’s just that, as a camper, working your way toward Point A3 may include some inherent degree of risk, and adding to it with driving or recovery techniques that can strand or injure you is a needlessly foolish risk that has nothing to do with the adventure quotient (unless you enjoy campfire stories about emergency rooms, rehab and pain-killers, or like to compare scars). Such people have a perfect right to post advice on forums. They also have the right to create videos of their approaches, make recommendations, and to basically instruct you on how to put yourself in jeopardy. It can be difficult to discern the competency level of who’s leading you down the garden path. Difficult, but critical. “I’ve always done it this way” is not much help if he’s always done it wrong but has lucked out so far. One YouTuber videotaped an extrication method he’d heard about and was trying for the first time on camera, but without the needed hardware bits and pieces to make it actually work. It failed badly. He titled and posted the video as a “How To” anyway, in order to get people to watch it. Made me wonder just how desperately lonely or validation-seeking some of these people are. In his follow-up video, he coughed up for the needed equipment, tried it, and it worked fine. But, he didn’t care for it because of its complexity, and decided in the end to recommend an approach guaranteed to damage equipment. Brilliant. Another teaches us to attach our snatch strap (used like a big rubber band to allow one vehicle to yank out another) to the tow ball on the rescue vehicle’s hitch. This can easily induce stresses it’s not designed for, and catapult the plum-sized, 2-3 pound solid steel ball back at you with very impressive speed. Luckily, no recorded fatalities so far (that I know of). Just Civil War-style maimings, but without the eagerness to employ a hacksaw as the remedy. This is the kind of instruction that’s worth every penny you pay for it.
One source of driving and recovery instruction that I do trust is Andrew St. Pierre White, a persnickety teabagger who has extensive overlanding experience all over the world, and teaches practices that maximize the odds of “arriving safely”. Many of his videos are available on YouTube, and all of them are available on his website, 4xOverland.com. There, you won’t find videos with rolled over or airborne vehicles, or people showing off pretzeled driveshafts. Its about how to succeed at the challenges of getting to where you want to go, intact. Should you lack the bandwidth for videos, he is an author as well. He intends to be at the Overland Expo West again this year.
I’m not going to get into traction aids like tire chains and straps here. I’ll mention traction boards, but I can’t promise much objectivity. These are like mini-surfboards a few feet long, with a highly textured upper surface for the tire to roll on and get some grip. If your tires sink into whatever, you dig clear what you can, then try to stuff one end of the traction board as close to being underneath the “bad” tire as you can. Presto, the tire now has its traction, and you glide up and out of the hazard. In practice, it’s not so carefree. If the tire can’t get a bite on the tip of the board, not much will happen. Once caught under the tire, the results vary wildly. Cheap and crappy boards and traction mats tend to either lay there and look good, or zip under the tire and eject or submarine on the other side. Highly regarded boards like the plastic Maxtrax from Australia work okay as long as you don’t allow much wheelspin. That would quickly shave off its plastic projections. Its classic predecessors, based on perforated and formed steel sheet, are more versatile, but weigh more and cost twice as much. The Maxtrax MkII boards are $300/pair, just so you know. That’s why some folks recommend carpet squares to vanners, but that’s a bit like Typhoid Mary. They’ve never actually used them themselves in a tough mud situation, but confidently spread the word to others as if they do work, which in mud they do not. So the hopeful victims lose 50 cents for the carpet sample, and $200+ for the tow truck. Learning curves are essential and beneficial, but less so when they come at a high cost, financial or physical.
Maxtrax cautions against using their traction boards as bridging ladders, or on hard or rocky surfaces. Some obstructions like deep gaps between rocks, or abrupt, high steps up or down, go much easier and safer with a ramp. Metal bridging ladders are made for this type of work, though nearly all bridging ladders are made for overlanders with light SUVs in mind. When your wheel loading is twice the usual, you have to start asking questions and weeding out the ones that will bend like wet spaghetti. Some off-roaders press pickup bed loading ramps and other more industrial products into service to try to trim back the cost.
A bridging ladder that actually works well and isn’t based on WWII technology is one from Crux Offroad. A simple, modular assembly of formed aluminum extrusions, the standard model handles 4,000 pounds per axle, while the heavy duty model introduced late last year is rated at 7,000 pounds per axle. Woof! I have reason to believe that these ratings are very conservative, too. Both versions are available in 4- or 5-foot lengths, making costs range from $350-$500 per pair, more expensive but more useful overall than the Maxtrax poly boards.
Unique inset ends make them less prone to lever up and whack the bodywork. Their drawbacks are that, with such an emphasis on function, they take up more space when stacked together, storage mounting may require more improvisation and, if you’re into fad and fashion, they do not come in a variety of gnarly colors. Bare aluminum is it. I was all breathy to get a pair of these, principally to deal with high steps and very deep, narrow washes/ruts I’ve encountered, but A] I lack the cash and B] I lack a place to store them without rigging up yet another bizarre external mount on the Intrepid. No room at the inn (truck cab interior), and you wouldn’t want to stow muddy ones back in the available carry bag. Enough, already. Not this year. I know where reverse gear is.
Back to plain traction boards, I’ll probably never touch one unless it can bridge the Ford as well, because of the cost. Why spend so much money for that when airing down tires for more traction is touted as being as effective as jamming a traction board under the tire of a bogged vehicle? And you don’t have to stop to retrieve the board, risking getting stuck again.
Airing Down Tires.
Airing down is the last topic I’ll handle, thankfully. Actually, I’ll brush off most of it to this post I put up a year ago, which is still perfectly relevant. Its not like these are Facebook blurbs going stale. But, with more exposure to more usage and more information, I’ll touch on two details, because the boring topic of tire air pressure can have profound results on your tour, good or bad. When tires work well, our thoughts don’t even brush past them once. When they act up for any reason, they resemble the source of misery personified. Titling this post “Understanding Your Tires” would make even me want to run the other way, but it’s always better to have a basic understanding of what’s going on with equipment, than to lack even a clue and simply follow some formula blindly, a formula that may not apply.
Here’s the straight poop. The sticker on the driver’s doorsill of your vehicle lists the tire air pressures that the vehicle’s manufacturer recommends for general use. Those values are very good. On a work vehicle, those recommended pressures will normally be based on making sure that the tires have enough air pressure to safely handle the maximum weight that the vehicle itself is rated for, the GVWR. Also, the sidewall of the tire has molded into it the maximum cold-fill pressure that should be used in that tire. The air pressure that you choose to maintain should be somewhere between the sticker value and the tire sidewall value, with the emphasis being toward the sticker pressure. Should you have some weight distribution difference on your vehicle that borders on being obnoxious, you can mismatch pressures in order to make sure that the more heavily-loaded pair will take the extra load without heating up, but you’ll need to find out the weight on each axle using a scale so that you know what you’re dealing with. More air pressure has the side effect of decreasing traction on pavement (racers adjust handling with air pressure), and if you don’t know what you’re doing, you can get some unhappy surprises on fast corners. Lumbering along is a good policy if you have some really funky weight distribution thing going.
Note: Don’t bother checking tire pressures after the vehicle has been driven (except maybe 6 hours or more afterward), and don’t ever bleed air out of hot tires to control pressures, even if the pressure is now above the sidewall maximum, which it may well be. Check pressures in the morning or whenever the start of the drive is, while the tire and ambient temps match. Adjust pressure then and then only – not on-route. Doing otherwise may well result in an under-inflated tire that runs too hot and seems to need bleeding again and again, at least until the carcass disintegrates. I’ve come across people who passionately argue that winter pressures should be different than summer, or that the inflation pressure must never be allowed to exceed at any time the maximum molded into the sidewall. The manufacturers of tires disagree, and specifically caution against this practice.
The vehicle’s doorsill sticker value is usually plenty good, apart from two situations. If you have the vehicle loaded up near or at the vehicle’s limit – which you should know by having it weighed and compared to the GVWR (also on the same sticker) – and will be spending much time at highway speeds, add more air pressure to the tires before starting out. Why? It boosts your margin of safety, which is the difference between what the tire is actually carrying right now and what it is capable of carrying at its current pressure. You want that to be a nice, big safety margin. To a tire, air pressure is life. Any given tire’s load capacity will drop if you lower its inflation air pressure or increase the vehicle speed. Go fast on an under-inflated tire, and the tire’s sidewalls can generate enough heat to permanently damage the tire’s innermost foundations. The sidewalls may bubble out first, to reveal that the tire is literally coming apart inside, but at any rate, the tire will fail early. It will usually fail after awhile, hitting you by surprise while you’re doing nothing wrong. Of course, it may also disintegrate then and there during that run.
I see that a lot with travel trailers and fifth wheels on the Interstate. The rated load capacity of trailer tires is noted on the sidewall as so-and-so pounds@60 MPH, along with the maximum cold-fill air pressure that the tire should have. To keep costs down, TT manufacturers usually fit tires which have a very thin margin of safety, the tires being pretty close to their load-carrying limits right off the bat. Therefore, trailer tires need to be kept right up near the max pressure molded into the sidewall in order to be able to cope with the load, and thus to limit heat buildup. Doing that is great! …But. But then many folks do the 75 MPH speed limit or exceed it, which adds heat and significantly chops away the load capacity of the tires. Sooner or later, blammo! The max load rating on the tire’s sidewall is at 60 MPH only, and while the capacity may increase somewhat at slower speeds, it will begin to nosedive at higher speeds. With the load being so close to the tire’s limits under optimum conditions, making something go non-optimal effectively overloads the tire. I mention trailer tires only because they make understanding the pressure/speed principle easier, but the same principle applies to cars and trucks. They’re just not quite so close to overload and speed limitations as trailer tires are. Never weighed your RV, truck or van fully loaded (or overloaded), and don’t plan to? Then you may want to consider keeping cold-fill tire pressures much closer to maximum. This won’t do you any favors off-road, but will help them survive their time on the Interstate at the speed limit. In large samplings, the majority of RVs have been found to be suffering an overload on at least one tire, so this isn’t as overly cautious as it might seem at first, and they aren’t just talking about 40-footers.
The second situation is if you bought store-exclusive branded tires priced lower than any other tire that chain offers, size for size. Tire manufacturers make a range of tire quality levels to accommodate the market, from value leaders to high performance. They each establish a certain minimum quality level that they will choose to offer as their own brand. Big tire chains contract with one of their primary suppliers to manufacture an exclusive model bearing their own brand name, the only available differentiator being price. It must sell at retail for less than any other tire model they offer. Apart from periodic promotions, the tire chain is not going to lower its customary profit margins on the new proprietary model, otherwise it would cannibalize all the other models with juicier profit margins, hurting more than helping the chain’s overall profitability.
They’re not in a market position to be able to “make it up with volume”. So the chain sets the retail price it wants for its tire, sets its minimum profit margin to be comparable to the other tire models it carries, and asks one or more tire manufacturers it carries to submit a bid to make the new in-house brand for them. Sure, manufacturers want to win the chain’s business, but they have an obligation to watch their bottom line as well. They aren’t going to be left holding the financial bag by sacrificing their own profitability. So they negotiate tire specs and construction with the chain in order to bring manufacturing costs in line with the tire’s low wholesale price. What results is a low cost tire which is lower in construction and/or rubber compounds than what the manufacturer would be willing to place its own brand name on. Then, along comes you, wanting to spend as little as humanly possible. You have it mounted on your loaded vehicle, and hit the highway or the gravel trail. You just might luck out and come out ahead in this game, but the overall odds are not with you if the tire is pressed to or beyond its limits, which will likely be lower than any other tire you can buy, particularly for off-road use.
Detail for geekoids: As in one of the photos above, most LT (light truck) tires also mold a service description into the tire sidewall. This is a code that refers to how fast a maximum-loaded tire at maximum inflation pressure can safely run. The code on my Coopers is 125/122Q, the first number set being for single wheels, and the second for duallies. Looka this here chart, page 10. The chart is from Goodyear, but what the codes mean is universal. Thus my tires at “125” means that the tire can handle a 3,640-pound load (at 80 PSI). The “Q” means it should be able to run at a sustained 99 MPH before it self-destructs. The second number “122” refers to duallys, where each tire can only be expected to carry 3,305 pounds due to the loading effects of uneven pavement. These charts let you see directly how reducing air pressure affects load capacity. (My own tires are left blank on this chart, but I can still get some idea for kinda-similar tires.) Passenger car tires often include a single service code on the sidewall, immediately following the tire size.
Considering all the woeful cautionary stuff above, you wouldn’t think I’d be suggesting that you deliberately lower inflation pressures well below the sticker value on your doorsill. As my earlier post explains, properly lowering inflation pressures does three good things on trails:
- It smooths the ride on rocky or washboard roads.
- It lengthens the tire contact area with the ground, increasing traction and helping to keep the vehicle from sinking into soft surfaces, etc.
- It decreases the likelihood of cuts and impact breaks.
Airing down also potentially includes 5 bad things:
- It exposes the relatively thin tire sidewalls to an increased risk of trail hazards and puncture. With a low enough pressure, it’s even possible to dismount the tire bead from the wheel rim, instantly letting all the air out. It can be remounted on-site, but the process can be a real bugger.
- It can make handling feel more vague or sloppy.
- Reinflating the tires takes considerable time with a decent air pump or air tank.
- Careless driving can damage the tire or wheel rim on obstacles.
- At any given speed, the increased sidewall flex will create much more heat.
This last point is the real bugaboo. There are a plethora of guidelines as to just how much pressures should be lowered. The one I’ve chosen places the wheel rim 25% closer to the ground than normal, though I’m not convinced that this percentage is appropriate for 10-ply E-rated truck tires. It’s intended for lighter SUVs with lighter-duty trail tires. Another guide recommends going no less than 25% of the maximum PSI molded into the tire sidewall. For SUV tires, Andrew White recommends an alternate based on ground surfaces, which range from 10%-50% of the doorsill sticker value.
Andrew White is the only advisor I’ve come across who has noted that low-profile 70-series tires such as mine do not respond much to airing down, in that the tire’s ground contact patch does not lengthen nearly as much as it does with the taller balloons used by off-roaders and overlanders alike. Those tires’ larger diameters lift the vehicle higher off the ground for improved clearance, soften the ride, and provide an ample contact patch when air pressure is lowered. Unfortunately for me, no taller tires are made which will fit my existing wheel rims, making a move to big soft pillows an expensive proposition. And even with new rims, that necessary E-class load rating narrows the tire field further. So, why would Ford decide to go with a tire profile that was once associated with sporty cars, and specify them for a full-size 3/4-ton 4×4 pickup truck? The answer is that, like Chevrolet, GMC and Dodge, they know that the vast majority of their buyers – including those who want pickups just to project an image – will gravitate toward a truck which will respond with authority carrying a load on pavement. Despite the 4×4 drivetrain, these vehicles will only occasionally go off-road, and when they do, it will be limited to gravel roads with some mud patches here and there. Their weight, long wheelbase and mammoth size make these trucks a very poor choice for serious off-roading , so there would not be much point in optioning them with tires guaranteed to give vague steering while they eat up suspension parts with their massive rotating weight. These pickups are destined to be work trucks, not trail tamers, and in the great scheme of things, there is so much else about them that inherently compromises rough-trail performance that adding tall mudders is like putting lipstick on a pig. Some individuals might do so to cope with local conditions or to compete in poor-traction contests, but they still won’t be able to get very far down any difficult Jeep trail. Taller tires simply make it a one-trick pony, and serious overlanding isn’t one of those tricks. The market for that brand of muy macho in new truck purchases is practically nonexistent, so they build for the best all-round performance in real-world use: construction and trades. If you want something else, you’ll have to open up your wallet in the aftermarket, and then live with what you’ve done – sans warranty.
Whenever tires are aired down, heat buildup will be a part of the picture – a big part. This will be no problem while lumbering slowly down a trail, but there are traditional guidelines for maximum trail speed based on the existing inflation pressure, which I mentioned in the earlier post. Then again, this is for light-duty tires that are slower to create heat than mine. So far, I’ve never found any speed guidelines for heavy-duty E-class tires that are aired down. So a step back is in order. At their foundation, all these guidelines are trying to do is to limit speed with lowered pressures in order to keep the tires from overheating and ruining them from within. After all, airing down tires may reap traction, flotation and smoothness benefits, but it also forces the tire into a precarious position if speeds are up. At walking speed, the underinflated tire will have no issues whatsoever with the load it’s carrying. But at some unknown higher speed, that low pressure will allow the sidewalls to generate enough heat to internally damage the tire. For any given pressure, what is that speed in my application? There are too many variables to make this easy or exacting, so perhaps it’s best to go back to where all these guidelines originated from: tire temperature.
In my tire, the “standard” sticker inflation pressure is 65 PSI, with a max limit of 80 PSI. I normally run them at 70 PSI, since I’m loading them right at my truck’s GVWR. This puts them well within their load limit at that pressure. On trail, the stiff sidewalls allow running inflation pressures lower (at 25 PSI) than the normal “overlanding” minimum of 50% of normal. (Typical SUV tires can often be run at half that, or less – but risks go up.) What’s my new speed limit, the speed where my tire transitions from being okay to being in danger of heat-induced carcass damage, a technical overload? I can trust in speed/pressure guides for lighter tires, or find an acceptable value out for myself. Aired-down speed limits apply to sustained speeds, where the tire gets no chances to roll slower and lose some heat. It’s not an absolute speed limit that the tire must never exceed, but you do not want to stay higher for long.
Experienced overlanders use this rule of thumb to avoid the risk of ruining aired-down tires: run at a set speed on the low side for awhile, then periodically get out and put your hand on the tire. If it’s just warm, maybe uncomfortably warm, you can afford to bump speed up a bit and retest later. The point where the tire feels coffee mug hot is the indicator that you have passed your safe cruising speed at your current inflation pressure. At that point you must either reduce cruising speed or raise inflation pressure, and retest. Heat gain will tend to be greatest on pavement and washboard dirt roads.
I suppose that this can be measured using an infrared temperature gauge. They do this with cars on race tracks, to try to get the rubber as soft and grippy as possible, but without frying any part of the tire. This allows them to monitor how pressure settings are working, and suspension settings for the track, with the goal for desirable street tire temperatures being between 140-170 degrees for maximum grip on pavement. Race tires operate at over 200 degrees, but they do not face road hazards either, and their service life is measured in minutes. On trail, there is no such publicized magic temperature limit for off-road tires – all you’re trying to do is to make sure there’s no chance of the interwoven carcass having an excuse to begin a hidden disassembly process that will eventually leave you with a tire to change out. Discounting the surface effect of prolonged sun exposure on one side of the vehicle, it comes down to being able to keep your hand on a tire sidewall without getting the hot coffee mug jerk-back. Vague, but simple.
I’d like to find out what my top cruising speed should be at 25 PSI inflation pressure. I will try this coffee mug approach when I get the chance, which is very seldom. That’s because I rarely get to reach even 20 MPH on most trails due to the Super Duty’s stiff suspension. Since I’m mostly exploring just to look for campsites, long stretches at moderate speeds don’t happen often. My trail showstoppers are rarely traction-related. They have to do with trails being too narrow or too prone to high-center the long Ford. Each obstacle is a freestanding decision to make for me, since 2WD mode is the norm. Although I occasionally need 4WD to press on ahead, I won’t 4WD into anything I’m not sure I can’t 4WD out of. Running solo, a significant risk is an unacceptable risk. Therefore, I think twice about going over sand or deep gravel with 2,600 pounds per tire. I’ve done it, but done it knowing that not making it means I have only a small shovel to address any issue, not a winch or other recovery device with the needed weight capability. I’ll let you be the hero!