Since cars only have four wheels, you’d think four-wheel and all-wheel drive would be the same, but there are actually some major differences in their functionality, when they should be used, and which vehicles possess them.
As a primer, it’s important to know that a majority of cars default to either front-wheel or rear-wheel drive. If you were to hop into a typical passenger car on a typical day, the engine’s power will be sent to either the front two wheels or the back two, meaning the other set of wheels follow the powered set’s lead. When it comes to braking, all four wheels receive power to help the car safely and evenly slow down.
With those basics in mind, let’s dive into the differences between all-wheel and four-wheel drive and how you can use them to become a better winter driver.
The fundamental purpose of all-wheel drive is to get your car in motion from a dead stop. In this mode, your engine powers all four tires simultaneously to help you move through snowy and rain-slicked road conditions better than when using only front or rear-wheel drive. If you’re stuck in the snow, you’re going to have a lot better luck with all four wheels moving instead of just two.
All-wheel drive also allows each tire to turn at its own pace. As you turn, the tires on the outside of the turn rotate faster than the tires on the inside, so all-wheel drive is the better option to avoid wear and tear on their tires and axles.
Many current cars have built-in tech which automatically shifts between two-wheel or all-wheel drive. This feature selects the most appropriate setting for you by accounting for road conditions as well as fuel economy.
According to Consumer Reports and Car and Driver, all-wheel drive is the standard for most modern passenger cars and SUVs because it’s even appropriate for year-round use, making it the bread and butter of winter driving.
If all-wheel drive is the bread and butter, you can consider four-wheel drive to be like a cake – only brought out for special occasions. This is because it’s meant for off-roading or extremely icy and slippery road conditions since it packs a bigger punch.
Four-wheel drive locks the front and rear driveshafts together and makes both of the vehicle’s axles rotate at the same speed. This allows each tire to slide freely over certain surfaces and then match up with the others to keep you, the driver, in control. With this setting, there will always be at least one front and one rear wheel being powered at all times. This extra power is great for slick or rough conditions but (unlike all-wheel drive) isn’t meant for paved roads. The power, as well as the locked axles, make turning difficult and dangerous on dry pavement, making turns more difficult to perform and causing your tires to shake and hop and you could cause a lot of damage to your axles.
The uses for four-wheel drive are so specific that only certain vehicles (usually pickup trucks and Jeeps) are built with it and the driver must press a button or pull a lever to shift into it.
Be in the Know Before There’s Snow
As if knowing the differences between all-wheel and four-wheel drive wasn’t hard enough, it can also be tricky to know which functionality your vehicle has due to the variety of terms and definitions across manufacturers. As a reminder: passenger cars and most SUVs are now typically made with all-wheel drives, while four-wheel drives are mostly relegated to larger SUVs, Jeeps, and pickup trucks.
To be extra sure which function your vehicle possesses, you can check the owner’s manual. If there’s a warning about using a certain setting on dry pavement, it’s a safe bet you have four-wheel drive.
Don’t Forget Your Tires
While both all-wheel and four-wheel drives can be exceptionally helpful in slippery, snowy conditions, they aren’t the end-all-be-all of safe winter driving. Besides making sure you have the skills to handle driving in wintry conditions, you might also want to invest in snow tires. The two drive settings we’ve covered are meant to help get you going and maintain control while your car is in motion, but snow tires (and your brakes) are the key to getting better traction and bringing the vehicle safely to a stop.
Driving safely in the winter is a combination of factors: road conditions, your skill, and, of course, your vehicle’s functionality. Understanding and using tools like all-wheel and four-wheel drive is a great place to start, but true expertise and confidence comes from training and practice.