By Eric Peters, Automotive Columnist
Trucks, like high-performance sports cars — like minivans for that matter — are specialty vehicles. Which means they’re compromised vehicles.
Some things, they’re very good at — usually, much better at them than a jack-of-all-trades family car.
A high-performance sports car, for instance, can be driven faster around a race track (or your favorite winding country road) than a family car before it approaches the limits of its ability to hold the road.
But the flip slide of this extra capability here is less capability there.
To wit: High-performance sports cars are usually awful in the snow. And they are awful in the snow to a great extent precisely because of the design aspects and features that make them adroit high-speed handlers on dry pavement — such as sport-compound (and short sidewall) “summer” tires and being low to the ground (and so having a low center of gravity).
In this case, you can’t have your cake and eat it, too.
Same goes for trucks — and SUVs built on a truck-type layout.
In order to be extra-capable off-road, on-road handling and stability are usually at least somewhat compromised.
Trucks and truck-based SUVs usually have more ground clearance — they sit higher up off the pavement — which is exactly what you want if you’re heading out into heavy snow or thinking about attempting a trek up a rutted, rock-strewn dirt road. (The lack of clearance, by the way, is one of the chief reasons why low-slung sporty cars suck in the snow. They bottom out sooner — and ride up on top of the accumulating snow, which reduces the ability of the tires to bite through the snow to the pavement.)
On the other hand, riding higher off the ground also means a higher center of gravity — which is exactly what you don’t want if the object is high-speed handling stability, especially in the curves.
The higher ground clearance/higher center of gravity typical of truck/SUV design is one of the primary reasons why they’re inherently less stable — and more prone to rollover accidents — than are cars. The auto industry has worked hard to make trucks and SUVs handle more like cars, to accommodate the conflicting demands and expectations of consumers, but they’re still compromised — and will probably always be compromised . . . so long as consumers expect vehicles to be rugged off-road as well as civilized on-road.
One method by which the car companies have attempted to crutch this Catch-22 is by fitting trucks and SUVs with car-type wheel and tire packages. Specifically, tall (and wide) wheels with short (and stiff) sidewall “sport” tires — as opposed to the Mud & Snow (M&S) rated tires — and not as tall, nor as wide — wheels you’d want if you don’t want to get stuck in the snow and mud. The end result is an automotive oddity. A truck/SUV that might actually be worse in the snow than a standard passenger car.
Again, you can’t have it both ways.
Same goes for the pros — and cons — of the truck’s (and truck-based SUV’s) four-wheel-drive system.
Most trucks and truck-based SUVs are rear-wheel-drive — with a part-time four-wheel-drive system optionally available. It is very, very important to comprehend the functional differences — and relative strengths and weaknesses — of truck-type four-wheel-drive vs. the increasingly ubiquitous all-wheel-drive, which (very confusingly) is often marketed as “four wheel drive” (see, for an example, the 2014 Jeep Cherokee; reviewed here).
Both systems do — technically — send power to (i.e., drive) all four wheels. But truck-type 4WD only sends power to the rear wheels when it’s not engaged, whereas AWD normally sends most of the engine’s power (90 percent being typical) to the front wheels — with (second Big Difference) power being automatically routed to the back wheels in the event the front wheels being to slip. With a part-time, truck-type 4WD system, the driver must engage the 4WD for any power to be routed to the front wheels. Otherwise, all the engine’s power is going to the rear-wheel-drive — and when in RWD, trucks and SUVs (which are light in the tail) are more prone to slipping and sliding than a FWD car!
But wait, there’s more.
Even in 4WD, a truck/SUV is not optimized for on-pavement driving. Most salesmen will not tell you this truth.
I just did.
Truck-type 4WD (which usually includes a two-speed transfer case and 4WD Low range gearing) is designed for uneven terrain, negotiated at relatively low speed. It is specifically not designed to enhance high-speed handing (and cornering) and you should avoid engaging it when driving on dry pavement — to avoid excess wear and tear. It also means you’re driving a two-wheel-drive (and RWD at that) vehicle when the system is disengaged.
AWD, on the other hand, is designed specifically for on-road driving in all conditions — wet, dry or snowy — and it provides a high-speed handling/cornering advantage, in addition to improved traction. Some of the latest systems are so sophisticated that they can direct the flow of power to individual wheels, in varying ratios, to enable the vehicle to corner at higher speeds without any loss of stability or control. This is something no truck-type 4WD system is capable of doing.
So what’s the advantage of truck-type 4WD? The two-speed transfer case’s gearing reduction provides extra pulling power for clawing your way out of deep mud and through deep snow. For climbing up rutted dirt trails — and so on. Also, the system is generally “heavier duty” than most AWD systems — and so can take a lot of abuse in an off-road context.
But these advantages may amount to not much if most of your driving is in fact on paved roads — even in the winter time. And there are some significant disadvantages — in addition to the handling/cornering disadvantages already described.
For instance, weight.
A truck-type 4WD system includes more components — most notably, the two-speed transfer case — but also a separate rear axle assembly. These parts are usually made of very heavy cast iron and add several hundred pounds to the vehicle’s curb weight, while AWD systems (which have no two-speed transfer case) typically add about 75-100 pounds and often less.
The higher the curb weight, the higher the vehicle’s fuel consumption. This is one reason why trucks and truck-based SUVs are — usually — so thirsty.
More gas is needed to get all that mass moving.
Which would be ok, if you got everyday capability enhancement — which (if you go off-road or deal with really severe conditions on-road routinely) you may indeed get. But if your driving is mostly on road — and rarely in severe conditions — then most of the time you’re lugging around useless dead weight that’s dunning you for dollars every time you gas up.
Trucks — and truck-based SUVs — also tend to be less space-efficient than cars (and car-based crossover SUVs). The reason for this has to do with the rear-drive layout that most trucks and truck-based SUVs are built on.
In a front-drive car, the engine is mounted sideways (“transversely,” in car industry lingo) rather than front to back (or “longitudinally”). The transmission and axle are snugged up against the engine as a single assembly called a transaxle. This greatly reduces the intrusion of the drivetrain into the passenger compartment, which usually means more legroom as well as more cargo room. The trunk/cargo area can be made larger because space isn’t taken up by a rear axle and related components. The floorpans can be flatter, too — because there’s no need for a “tunnel” to accommodate a driveshaft from the engine/transmission up front running to the rear axle in the back.
All else being equal, a truck or SUV of a given size (e.g., mid-size or full-sized) will have less interior room for people and cargo than a same-size car, crossover or wagon. The third row, especially (in larger models) is almost always more cramped than the third row in a crossover SUV or minivan.
None of this means trucks — and truck based SUVs — are bad. But it does mean they are different. It’s a good idea to know up front what you’re getting into.
Both pro — and con.
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