Four-wheel Drive or All-wheel Drive? That Is the Question

Measures of Control

Though casual car shoppers may speak of four-wheel drive and all-wheel drive as if they’re interchangeable, that’s far from the truth, Damon Cartelli says. Which system is preferable comes down to how that vehicle will be used.

“Any time you have an option that adds security — that allows people to drive to their destination with a little more security than in a traditional front-wheel-drive vehicle — people want that,” said Cartelli, president of the local Fathers & Sons chain of auto dealerships.

But while four-wheel drive dominated the market for a long time, all-wheel drive has long been recognized as the superior option for driving in inclement weather — including those snowy and icy days of a typical Massachusetts winter.

“With four-wheel drive,” Cartelli said, “each tire receives 25% of the vehicle’s power at all times. So, while a rear-wheel drive car gets 50% in each of the two rear wheels, with four-wheel drive, the power is broken down evenly between right front, right rear, left front, and left rear.

“The difference with all-wheel drive is, the system has the capability of transferring power to the wheels that are gripping, based on sensors detecting which wheels have lost traction,” he continued. “The result is better traction in wet or inclement weather — or any weather, for that matter.”

Cartelli said Audi was a pioneer of all-wheel drive back in the 1980s with its Quattro system, which helped it dominate rally racing for a decade. “Audi was eventually banned from this race circuit because the Quattro system gave them an unfair advantage against rear-wheel-drive cars.”

Today, he noted, all-wheel drive is a selling point in a wide range of cars for drivers who want stability in any weather condition.

“If you’re not buying a truck, you’re looking for classic all-wheel drive, and you don’t have to worry about anything. You get in and do your thing,” added Brian Farnsworth, a sales consultant with Marcotte Ford in Holyoke, which features four-wheel drive in Ford trucks and larger SUVs, like the Expedition, but all-wheel drive in cars and smaller SUVs.

“The main thing with all-wheel drive is, there’s no user input. You don’t have to select it; it’s always monitoring road conditions and what you’re doing, whether that’s steering, braking, or accelerating,” Farnsworth noted.

The latest all-wheel-drive systems use high-tech software and wheel sensors to detect wheel slippage more quickly than ever before, then react by activating traction control to reduce that slippage while rerouting engine torque to the wheel with the best grip on the road — as opposed to the evenly divided torque of four-wheel drive.

“It may sense when you’re taking a corner too quickly and transfer power to the wheels that are getting the grip,” Farnsworth said. “In that scenario — in any scenario, whether it’s hitting ice, sand, whatever — it senses spin in milliseconds, sometimes correcting it so that it doesn’t happen in the first place. Same thing when you take an off ramp too quickly, things like that.”

It also automatically reverts to two-wheel drive when cruising on the highway to improve fuel economy, he added.

“Four-wheel drive is a lot more heavy-duty, more work-oriented, for things like towing a boat out of the water, towing up a grade, things like that,” he went on. “It can’t be used on dry pavement, so if you take that off ramp too quickly, it doesn’t help you.”

Pros and Cons

In short, dealers say, the choice often comes down to how much off-roading a driver expects to do.

Four-wheel drive, they note, provides added traction when needed and is generally less expensive than all-wheel drive because it’s based on simpler technology. And, of course, it’s the preferred system for difficult terrain.

However, it doesn’t provide extra traction and better handling in everyday driving situations — but drivers often believe it does, leading some to take more chances on the road. The driver also has to actively turn four-wheel drive on and remember to turn it off afterward to prevent draining fuel economy.

On the other hand, all-wheel drive increases grip and control under any condition and works all the time. While it can’t match the levels of traction in low-speed off-roading that traditional four-wheel-drive systems provide, all-wheel drive does pose some clear advantages, notes Peter Braun at digitaltrends.com.

“In the sort of winter road conditions that most drivers experience, it’s nice to have a drivetrain, like a modern AWD system, that responds instantly without the driver having to toggle any switches,” he writes. “In addition, most vehicles featuring AWD tend to have better weight distribution, which also aids in traction.”

For many drivers, he added, particularly those down south who rarely experience wintry driving conditions, basic front- or rear-wheel drive is fine. Still, many drivers value the added level of comfort and peace of mind an all-wheel-drive system provides.

Farnsworth said Ford, like other car makers, has incorporated a number of different all-wheel-drive systems that shift power around in different ways, but one thing they all have in common is the ability to operate without any user input or thought, and then switch back off under normal conditions. “It’s always on when you need it most, but always trying to save you gas when you don’t.”

That does not, however, free drivers from basic common sense when operating in wintry weather, like speeding down hills during snowstorms.

“Some people think they’re invincible. They think if they’re going down a hill and hit ice, they’ll be fine because of their four-wheel or all-wheel drive,” he explained. “But it only helps you get going. It doesn’t help you stop.”

It’s also no substitute for tires that have proper tread, Farnsworth added. “It really all comes down to this: no matter what kind of drive train you have, your tires are the most important thing. The fanciest all-wheel drive in the world is not going to help you if your tires are bad. It’s just simple common sense. It’s constantly monitoring slippage, but if nothing’s getting a grip, if the tires aren’t catching, you’re not going anywhere.”

That’s a common refrain in the industry, even among those who sing the praises of all-wheel and four-wheel drive.

“You can’t put a price on safety, but shelling out [for all-wheel drive] isn’t a get-out-of-a-ditch-free card either,” writes Ben Bowers at gearpatrol.com. “No matter what you wind up picking, our advice is to study up on good winter driving skills, focus on regular maintenance, and work on improving your decision making behind the wheel first. After all, at the end of the day, it’s the man behind the machine, not the other way around.”

Peace of Mind

Even today’s front-wheel-drive vehicles handle well in wet or snowy weather as long as they’re fitted with the proper seasonal tires and the driver is careful, Cartelli said. But for people who don’t have the option of staying home from work during those New England snowstorms — doctors and nurses, for example — all-wheel drive brings an added layer of comfort. “If you have to be somewhere no matter what, all-wheel drive with the right tires will get you there.”

No matter how they use their vehicles, Farnsworth added, purchasing drive-train options beyond front- or rear-wheel drive is an investment worth making, if only for the peace of mind.

“All the new SUVs drive much like cars; the all-wheel-drive systems are not as bulky, so they don’t drive like a truck,” he said, adding that many drivers come to take the systems for granted — until it’s time to buy a new vehicle. “When they come in, it’s the first thing out of their mouth: ‘I need that all-wheel drive.’ It makes them feel safer; it’s definitely a security blanket for them.”

Joseph Bednar can be reached at [email protected]