All-Wheel-Drive or Four-Wheel-Drive

September 7th, 2021 by

Looking for a vehicle that’s great for snowy or icy roads? Then your shopping options include vehicles equipped with all-wheel drive (AWD) and four-wheel drive (4WD). Both drivetrains have an advantage when it comes to traction under wet or slippery conditions. However, these systems operate differently from one another.

Read on and learn the differences between AWD and 4WD, as well as which system is the best choice for your driving needs.

What’s the Difference?

In a nutshell, both AWD and 4WD systems provide power to all four wheels to combat wheel slip and maximize traction for acceleration. However, both systems differ in their approach.

All-Wheel Drive

AWD systems are optimized for on-road use and, as a result, are usually found in mainstream SUVs, wagons and even a few sedans. Most AWD systems use a center differential between the front and rear axles while others use a clutch-pack coupling. Either way, AWD systems can send varying amounts of power to the front and rear tires, as needed.

The upside to AWD is that it ensures seamless traction regardless of road and weather conditions. AWD systems are also lightweight in their design, which also helps with fuel economy. On many AWD-equipped vehicles, drivers can toggle through special settings that optimize the AWD system for specific terrain or road conditions.

AWD systems come in part-time and full-time varieties. The former drives the front or rear wheels most of time and only sends power to the other two wheels upon detecting wheelspin, ensuring surefooted handling under demanding road and weather conditions. The latter drives all four wheels all the time, giving the vehicle better acceleration on dry pavement and more traction in bad weather.

Four-Wheel Drive

4WD systems, on the other hand, are optimized for off-road performance. Instead of using a center differential, 4WD systems rely on a transfer case to distribute power. Think of a transfer case as a locked differential that sends a fixed amount of power to each axle. Most 4WD systems have a “4-LO” setting for rock crawling and other low-speed situations that call for lots of traction, and a “4-HI” setting that can be used at higher speeds. There’s also a default 2WD mode that exclusively drives the rear wheels, on most models.

Unlike an AWD system, both the front and rear driveshafts on a 4WD system are locked together when engaged in 4-HI or 4-LO, causing them to rotate at the same speed. While that guarantees power delivery to the tire with the most traction, it also makes on-pavement cornering difficult. That’s why 4WD systems are typically reserved for SUVs and pickup trucks designed for off-road duty.

Like AWD systems, 4WD systems also come in part-time and full-time versions. Part-time 4WD systems require you to engage 4WD when you need it via a lever, push-button or knob. Older 4WD systems may also feature manually-locking hubs that require you to exit the vehicle and lock each wheel by hand.

Which Works Best?

For everyday driving that occasionally calls for a boost in traction, AWD is the way to go. It’s also the simplest option for anyone in search of set-and-forget usability. You won’t suffer as much of a fuel penalty as you would with a 4WD system, plus you’ll also enjoy better cornering and overall handling.  

For off-road enthusiasts who regularly deal with rugged terrain, however, 4WD is the best option. 4WD systems give you greater control over your vehicle’s traction needs. The actual components are also more robust, ensuring greater longevity under harsh conditions. That adds weight, however, with the end result being poorer fuel economy when compared to an AWD vehicle.

Don’t Forget About Winter Tires

While AWD and 4WD systems help immensely with traction and acceleration, its your tires that ultimately play a big role in keeping your vehicle under control on snowy and icy roads. The all-season tires that come with most AWD and some 4WD vehicles are not as ideal for snow- and ice-covered roads as a good set of winter tires.

Unlike all-season tires, winter tires feature tread designs and rubber compound specifically formulated for winter conditions. Wider grooves, deeper channels, tread compound that stays pliable in cold weather, and grip-enhancing sipes all combine to cut through deep snow and enhance traction.

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