When language is misused, people tend to get confused and misled.
One example of this is the way “4WD” is now being regularly used to describe that which isn’t. Or rather, wasn’t historically speaking.
Before the rise of the Universal Transportation Appliance or UTA, the car-based crossover “SUV” (in air fingers quotes because that’s another example of semantic abuse) a 4WD-equipped vehicle was one that had a truck-type system, based on a rear-wheel-drive layout with a two-speed transfer case and Low range gearing.
The system normally routed all of the engine’s power to the rear wheels only, in 2WD High. When 4WD High was engaged, the power was split 50-50 front to rear. In 4WD Low, the gearing was altered to greatly multiply the available leverage, for force-fording through deep snow or thick mud, etc.
Obviously, these attributes are desirable if you need or want to force-ford your way through deep snow or thick mud, etc.
The problem is that the typical UTA–the crossover “SUV”–doesn’t have them.
What the UTA generally is an all-wheel-drive (AWD) system, which is not the same thing as a 4WD system.
Enter the confusion. Deliberately fostered. Easily done, too.
Technically speaking, AWD is 4WD in that it is true that all four wheels are driven. But it is also as misleading as saying you’ll save “up to” such and such a sum if you buy X to say that AWD is the same as 4WD.
Most AWD systems, to begin with, are front-drive-based and in normal driving situations, send all or nearly all of the engine’s power to the front wheels only.
This is actually a benefit, by the way in terms of initial traction/grip because you’re less apt to experience slip when the car pulls itself forward than pushes itself forward. The first production FWD car, the Citroen Traction Avant of the ’30s, touted just that.
The name means traction forward.
Generally speaking, FWD can obviate the need to buy a 4WD-equipped vehicle in that an FWD car (or UTA) will have more grip on a wet or snow-slicked road than a rear-drive car or a 4WD vehicle that’s operating in 2WD High (which is rear-drive, only).
The AWD system also automatically routes a certain amount of engine power to the rear wheels without the driver having to engage anything. In most 4WD systems, the driver must engage the 4WD to get 4WD (some of the newer systems do this automatically, furthering the confusion).
The AWD system can continuously vary the power split, front to rear by as much as 100 percent in either direction, based on whether the front or rear wheels have the most grip.
Most 4WD systems lock the split, 50-50 as described above.
AWD can actually provide more traction on wet/snow-slicked roads.
It also confers a lateral traction advantage that 4WD does not. Simply, most AWD systems can tailor-adjust wheel slip from side to side as well as front to rear. This capability, in conjunction with ABS application of the brakes, can be used to greatly increase high-speed cornering grip/stability on dry (as well as wet/snow-slicked) pavement.
It is why many high-performance cars are equipped with AWD rather than 4WD.
Most 4WD systems do not enhance high-speed handling tenacity and, indeed, it’s not advisable to engage the 4WD unless there is snow on the road or you are off the road, and not going fast in the curves.
The reason has to do with the differential in rotational speeds of the inside and outside wheels during cornering. This can bind the axles up and cause mechanical problems/premature wear of the components.
So, slow down when the 4WD is on.
4WD systems, as historically defined, have that two-speed transfer case and the gear-reduction functionality that endows them with greater low-speed force-fording capability in very low traction situations, such as slogging through deep, unplowed snow or mud, off-road.
Some AWD systems emulate this functionality by using their transmissions to multiply the effective gearing and they can be quite capable, too. But they aren’t as rugged, because they are not built as heavy, usually. The cases and what’s in them generally aren’t as sturdy and not designed to handle very high-load situations as well as 4WD systems, which are truck-type systems rather than passenger car-type systems.
This brings us to the other semantical thing and a confusing overlap between SUV and crossover.
When 4WD badges were applied to the tailgates of trucks, SUVs were based on trucks. The former bed was enclosed, so as to carry more people than 4×8 sheets OSB. But underneath the floorpans, it was still all truck.
Crossovers look like SUVs but are based on cars, and usually (though not always) front-wheel-drive cars. It is why most crossovers have or offer AWD rather than 4WD even if that’s not what it says on their liftgates.
If you go by historically accepted definitions. But those definitions have also been obscured by referring to crossovers as SUVs, which they aren’t.
It’s not that one or the other is better or worse. It’s that they are not the same.
Buyers would be better served if they understood what they were looking at buying, which used to be much clearer when there were 4WD-equipped SUVs and pickups, and AWD meant something else.
Eric Peters lives in Virginia and enjoys driving cars and motorcycles. In the past, Eric worked as a car journalist for many prominent mainstream media outlets. Currently, he focuses his time writing auto history books, reviewing cars, and blogging about cars+ for his website EricPetersAutos.com.
Editor’s Note: The opinions expressed in this article are those of the author.
