AWD vs. 4WD vs. 2WD Systems
AWD vs. 4WD: Which should you choose?
When you’re looking to buy your next vehicle, one of the many factors you’ll want to consider is whether you need or want a Four-Wheel Drive (4WD), All-Wheel Drive (AWD), or Two-Wheel Drive (2WD) vehicle. This will be true no matter what kind of vehicle you wish to purchase — from sports cars to SUVs, all gas-powered vehicles, diesel-powered vehicles, and all types of EVs use one of these systems.
Here, we’ll define the basics of AWD vs. 4WD systems and outline why you might opt for one over another. We’ll also cover a few basics about 2WD, but we pay particular attention to the differences between 4WD and AWD systems, as the two are often spoken of interchangeably, despite having unique characteristics.
What is AWD?
AWD is a drive system in which the engine or electric motor output can be delivered to all four wheels. AWD systems operate autonomously and require no additional driver action.
How does AWD work?
Before learning about how AWD works, it’s useful to understand why your vehicle might need it. To do this, imagine the tire tracks a car would leave as it was turning in the snow or dirt. Looking at those tracks, you would see that the front tires travel further than the rear, and that the tires on the “outside” of the turn travel further than tires on the “inside” of the turn.
Since the tires in this situation all need to travel different distances, they should not be “linked” in a way that requires them to rotate at the same speed. From a technical standpoint, this means that cars require a differential at each axle that allows tires to spin independently.
In both AWD or 4WD vehicles with an engine or an electric motor, another device located between the front and rear axles (either a transfer case, center differential, viscous coupling, multi-plate clutch pack, etc., depending on the vehicle) gives the front and rear axles the independence that they need to operate.
Part-time AWD
A vehicle with part-time AWD takes engine power from the transmission and splits it between the front and rear axles. In most part-time AWD vehicles, the power to the front or rear axle can be autonomously “turned off” completely or varied from 0-100%. Driving just one axle helps with efficiency, as it takes less power for the engine to spin just two wheels instead of four. AWD vehicles with a 0-100% variable output can help make the vehicle more responsive and stable in low traction driving conditions.
Battery electric vehicles with AWD usually have a motor on each axle and front/rear differential action is provided by motor control. Hybrid electric vehicles with AWD often use a gas engine for driving the front wheels and electric motor(s) for driving the rear wheels, offering AWD benefits without the center drive shaft, which reduces weight and, sometimes, improves interior floor space.
Part-time AWD is more common than full-time AWD. The majority of AWD vehicles are derived from front-drive vehicles and operate as front-drive until AWD is needed, like the Mazda3, CX-5, CX-50, and CX-30.
Others at the performance or premium end of the spectrum — like the Mazda CX-90 — are rear-drive biased and tend to have a more sporty feel.
Full-time AWD
Full-time AWD sends power to the front and rear axles all the time. This approach to AWD gets less common every year, as more AWD vehicles drive only one axle for peak efficiency and add drive to the other axle when needed.
Mazda’s i-ACTIV AWD®
In some all-wheel drive systems, like Mazda’s i-ACTIV AWD ®, the system has sensors which detect the driver's intentions and road conditions, the system calculates how much torque should be sent to the rear wheels in order to prevent the front tires from slipping, and almost instantaneously sends a command to the AWD coupling unit to send the appropriate drive force to the rear.
Vehicles typically equipped with AWD
AWD systems are common on a broad range of vehicles, from crossover SUVs to performance luxury cars (gas and electric). For example, every Mazda vehicle except the MX-5 Miata comes equipped with AWD on at least one trim level.
Benefits of AWD
• Superior acceleration in low-traction conditions like snow, hail, or mud
• Improved steering response under acceleration
• Sensors and processors work faster than humans
• Completely automatic, one less thing for the driver to think about
• Potentially higher resale value
What is 4WD?
Part-time or Full-time 4WD, also referred to as 4x4, gets its name from the engine’s ability to apply torque to all four wheels at once and rotate the wheels at the same speed. When 4WD systems are activated, if one or two wheels lose traction or grip, the other wheels are still able to propel the vehicle forward. The capacity to operate in this mode is what makes 4WD vehicles ideal for operating in off-roading and in more extreme weather conditions, including heavy amounts of snow and deeper loose terrain.
How does 4WD work?
With 4WD, power flows from the transmission to a transfer case, a selectable secondary gearbox that feeds power to the rear axle only or front and rear together, depending on what the driver has selected. In some vehicles, the transfer case may contain options for center differentials — an “Auto” setting lets the system perform like an AWD. Unless the vehicle has an “Auto” mode, it should not be driven on dry pavement, as both front and rear axles will operate at the same speed in 4WD. Part-time 4WD systems can be selected from 2-high to 4-high or 4-low, this is all done through the transfer case. Full-time 4WD is driving all four-wheels at all times without the ability to shift out of 4WD into 2WD.
Meanwhile, 4WD high, low, or locked settings indicate the axles are linked together and should not be used on surfaces with good traction, such as dry roads. More on these settings below.
4WD driving options and settings
4WD vehicles can offer a range of driving options, including 4WD, 2WD, 4 Auto, high and low range, as well as several differential locks. These are selected by the driver using a dashboard switch or a floor-mounted shifter. Let’s break each option down.
4WD
Four-wheel drive sends power to both axles. This is used where surface traction is marginal–slick boat ramps, deep snow, muddy fields, rocky or rutted trails, and so on.
2WD
The 2WD setting can be used to maximize efficiency (the engine uses less power when spinning just 2 wheels instead of 4) and when rear-wheel drive dynamics are most useful.
4WD Auto
When 4WD Auto mode (sometimes called simply “Auto”) is selected, it mimics an AWD system and can be used on pavement. Auto mode is standard on some luxury models and very highly optioned pickup trucks.
Low range
In most cases, 4WD vehicles offer a selectable set of reduction gears called “low range” (colloquially 4-low or 4-lo) that provide maximum torque. This is especially useful in situations when climbing obstacles, powering tires in mud or sand, or towing a heavy load up a steep incline off-road. The majority of vehicles if equipped, require stopping before engaging low range.
Differentials
A 4WD vehicle is also more likely than an AWD vehicle to offer locking differentials that will drive both tires on an axle even if one is off the ground. Most locking differential systems are limited to use in 4-low only.
There are differentials in the rear and front axles. If your vehicle has a locking differential (rear axle or both front and rear) you may choose to use them on terrain where traction is very limited or varies side-to-side.
As mentioned above, an AWD vehicle or one with 4WD offering an Auto setting may also contain a center differential allowing it to operate on the highway but can lock for when more traction is needed. This is achieved automatically by the vehicle according to whatever drive mode (4WD Auto, 4WD high, etc.) the driver has chosen.
Neutral
Finally, most 4WD systems also offer a Neutral gear position within the transfer case, which makes them easier to tow.
Vehicles typically equipped with 4WD
4WD systems are found in many midsize and all full-size pickups, most large pickup-based SUVs, and other vehicles designed for off-highway. If a vehicle was built using the body-on-frame method design, it typically offers 4WD.
Benefits of 4WD
• Robust design allows for driving in more difficult terrain and/or conditions
• Torque multiplication of low-range gearing puts 2 times the torque to the wheels
• Driver selectable for conditions and preferences
• Superior off-highway performance
• Ideal for towing up steep boat ramps or on muddy trails
What is 2WD?
2WD sends power to either the front or rear wheels — primarily the front wheels for economy cars, sedans, hatchbacks, and minivans, and the rear wheels for most sports cars, luxury and sport sedans, big SUVs, and most pickup trucks and heavy-duty vans.
In general, the more power a sport sedan has, the more likely it is to use AWD because acceleration comes from power and traction. But remember: power is not the only way to enhance performance. For example, the Mazda’s MX-5 Miata prioritizes a lighter weight and responsive driving dynamics over outright horsepower; it features rear-wheel drive.
AWD vs. 4WD: Which should you choose?
Ultimately, whether AWD or 4WD is better for you comes down to your lifestyle and preferences.
AWD is a great option for drivers who neither want nor need to think about how their car propels itself. It is also ideal if you want more confidence in your car’s ability to accelerate in various driving and weather conditions (although a 4WD with a 4-Auto position can do the same thing).
If you regularly drive in very rough terrain or deep snow, a 4WD vehicle may be a better choice for your needs.
Which is better in snow and ice?
If you’re plowing through snow drifts, the robustness and low- range driving options of a 4WD system can serve you better than an AWD system, but both systems are advantageous in handling snow-covered driveways or hills. Of the two, AWD is a simpler system for a driver to navigate.
An AWD system and dedicated winter tires provide better traction in winter weather than just one or the other; neither AWD nor 4WD serves as an alternative to winter tires.
Most AWD and 4WD systems detect a tire slipping before any human does and make the necessary adjustments immediately, but skilled and practiced driving will always be one of your best tools, no matter the conditions on the road.
It’s also important to remember that once you’ve traversed that snowy hill, neither AWD nor 4WD will benefit you coming down. That’s where brakes and the friction interface between tires and a cold, wet, or icy surface come into play.
To put it another way, if you pit an AWD system on all-season tires against a 2WD system on winter tires, the AWD may accelerate better, but the 2WD’s winter tires will change direction and stop notably better on snow and ice.
Which is better off-road?
Any vehicle can venture off the beaten path, but the further off or more beaten the path is, the more preference skews to 4WD. This is because of 4WD’s low-range gearing, robust drivetrain, and the nature of body-on-frame trucks to be built with materials (such as steel frames, skid plates, and iron axles) that make them better able to take certain levels of abuse.
However, an increasing number of crossover SUVs, many of which feature AWD, are being constructed with off-roading in mind. The Mazda CX-50, for example, is a CUV that combines off-road drive mode with i-ACTIV AWD® to provide refined performance on rough terrain.
Meet Mazda’s AWD vehicles
Mazda’s i-ACTIV AWD® system is standard on all Mazda crossovers and optional on the Mazda3 and hatchback. Both the CX-90 and CX-90 PHEV offer a rear-biased version of i-ACTIV AWD® for the same benefits and excellent handling.
To learn more and experience the difference of driving a Mazda, explore Mazda’s line of vehicles online or take one for a test drive at a Mazda dealer near you.
This article is intended for general informational purposes only and is based on the latest competitive information available at the time of posting. Information herein is subject to change without notice and without Mazda incurring any obligations. Please review a variety of resources prior to making a purchasing decision. Visit Resource Center for more articles.