The main difference when comparing AWD vs. FWD is where the engine sends power. In vehicles with front-wheel-drive (FWD), the engine only powers the front axle and wheels, whereas, in AWD vehicles, the engine powers both front and rear axles. Several manufacturers, such as Toyota and Honda, offer many models in both FWD and AWD options, so it’s crucial to know the difference
Deciding between these two powertrain options depends on a lot of factors, not much different than deciding to get a big V8 or a more fuel-efficient turbocharged engine. The main differences largely have to do with your expected usage and your budget. This article will point out several powertrain types, and the pros and cons of each. This will help you understand which option is right for you.
Here's a brief rundown on the four types of wheel drive systems:
Front-Wheel-Drive: The vast majority of new cars on the road today are front-wheel-drive vehicles, including almost all models of SUVs and crossovers. For a front-wheel-drive vehicle, the engine and transmission are under the hood and they power only the front wheels. There is no mechanical connection between the engine and the rear axle. Since the drivetrain is positioned in the front and pulls the vehicle’s weight, the effect of oversteer (rear end of the vehicle sliding out when cornering and causing a tighter turn than intended) is limited. FWD cars are good at climbing hills and perform well in slippery conditions. From a manufacturer's standpoint, FWD vehicles are beneficial because they are cheaper to manufacture and use space more efficiently.
Rear-Wheel-Drive: Rear-drive systems are usually found in sports cars, pickup trucks, older truck-based SUVs, and luxury high-performance sedans. It is a two-wheel drive system that pushes the car from the rear axle. Rear-wheel-drive systems (RWD) enable better handling in performance cars by distributing weight more evenly. Also, since the front wheels aren't in charge of both steering and powering the vehicle, makers of rear-wheel-drive vehicles are free to tune the suspension system for handling superiority. These days, many performance RWD cars typically have AWD options available as well. RWD trucks are made with robust and heavy parts that provide better traction when hauling a heavy load. Rear-wheel drive trucks are also generally lighter than their four-wheel-drive counterparts, which allows for higher towing and payload capacity. However, RWD vehicles have inferior traction control when road conditions are slippery.
All-Wheel-Drive: AWD systems deliver power to each corner of the vehicle, similar to 4WD cars. However, unlike 4WD cars, AWD is always engaged and provides varying amounts of power to the axles depending on traction conditions. All-wheel-drive systems primarily power one set of axles, either front or rear. When the car senses traction loss in one axle, it will automatically divert more power to the other axle to compensate. Not all AWD systems utilize the same power ratio. For example, Subaru’s crossover’s all-wheel-drive system continuously sends at least 20% of the engine’s power output to the rear axle, with the possibility of directing more if necessary. Other systems exclusively power the front axle and only rebalance engine output to the rear when the front tires lose traction. The always-on nature of all-wheel-drive is appealing because the driver is not required to manually change anything in order to get extra traction. The car is ready and decides when and where traction is needed.
AWD cars work well in moderate off-road driving situations or when driving conditions are prone to change due to terrain variation or volatile weather conditions. In addition, AWD vehicles provide great overall traction during acceleration and cornering due to all four wheels being engaged, and actively adjusting how much power is sent to each wheel. AWD systems are commonly found in car-based SUVs and minivans. They also make an appearance as an option for performance cars that are normally rear-wheel-drive or front-wheel-drive.
Another all-wheel-drive option has recently entered the market, electronic AWD. Toyota uses this on some of its hybrid vehicles, like the Prius AWD-e. Under normal operations, the front wheels drive the car, but while accelerating in slippery conditions an electric motor can temporarily add power to the rear wheels to help the vehicle get moving. It is a little different than traditional all-wheel-drive vehicles because the electric motor is not mechanically connected to the gas-powered engine, only via electrical cables. Electric cars, like those from Tesla, can also offer AWD. Using two, three, or four electric motors to power the wheels for maximum traction.
Four-Wheel-Drive: Four-wheel drive systems (4WD) can be turned for extreme off-road uses like traversing over deep water, scaling boulders, or climbing steep hills with poor surface traction. When enabled, 4WD systems send power to all four wheels using front and rear differentials plus a transfer case that distributes power equally regardless of traction. In addition, some 4WD have two gear ranges, high and low. The low gear range proves especially helpful when low-speed climbing power is required. There are three different mode toggle options in modern four-wheel-drive vehicles. Full-time systems are always engaged, automatic systems switch between 2WD and 4WD automatically, and part-time systems require the driver to manually switch between two-wheel-drive and four-wheel-drive modes. Driving a part-time 4WD vehicle on the pavement with 4WD enabled can cause damage to the vehicle's drivetrain.
Is an All-Wheel-Drive or Four-Wheel-Drive vehicle worth it?
It depends on the driving conditions you plan to encounter. Two-wheel-drive cars handle rain and light snow just fine, with front-wheel-drive cars generally beating out rear-wheel cars when it comes to traction in slippery conditions. Rear-wheel-drive cars excel when performance is critical (although all-wheel-drive systems can provide more traction). All-wheel-drive vehicles are great for light off-road driving and typical snow conditions. If you're powering through heavy snow or tackling extreme off-road terrain, a four-wheel-drive vehicle with high ground clearance and a low gear range is the set of wheels you should be looking for.
In addition to weather and terrain conditions, fuel efficiency is another factor that should be considered. Both four-wheel-drive and all-wheel-drive systems contribute substantial heft to the vehicle, so you end up trading better fuel economy for that extra traction. Sending power to all four wheels when it isn't necessary also contributes to more mechanical drag and reduced efficiency. Some all-wheel-drive systems now automatically disconnect power going to the rear axle when the system determines the front wheels have sufficient traction.
Traversing Winter Terrain
Safety and handling is another major concern. Many potential car buyers view all-wheel-drive and four-wheel-drive SUVs as safer due to the increased traction they provide. However, that straight traction contributes less to assist in safer turning or braking, especially when ice is a factor. Sure, the robust traction is helpful when you need to get going, but stopping is another story. Four-wheel-drive and all-wheel-drive cars are involved in icier condition-related accidents than their lighter two-wheel-drive counterparts, and their drivers' misconceptions about the limitations of their 4WD and AWD drivetrains certainly plays a part. Even on dry streets, heavier four-wheel-drive and all-wheel-drive vehicles require more distance to come to a complete halt.
When driving through winter weather, you can't go wrong with a set of winter tires. A set of dedicated snow tires should be budgeted into the purchase of any vehicle if you live in an area with wintery weather. Snow tires vastly outperform all-season tires when temperatures dip, and ice or snow covers the road. Numerous independent studies have shown that good tires play the largest part in determining a vehicle's safety performance when driving through snow and ice. That is because snow tires are made from a softer kind of rubber than standard tires. Their more pliable texture enables superior traction when the temperature drops. Besides, winter tires feature specialized treads that are designed for carving into the snow and ejecting it out of the way. Snow tires are embossed with a three-peak mountain and snowflake logo, so it's easy to see if the tire you're looking at passes snow performance standards and is rated for winter driving.
To Sum it Up:
If you are mainly looking to drive in the city, a two-wheel-drive car is all you need to zoom around town. Throw a set of winter tires in places with occasional snowfall, and it will perform surprisingly well. This is the cheapest option since all-wheel drive and four-wheel drive vehicles have higher pricing right out of the dealership and are less fuel-efficient, leading to increased expenses down the line. A front-wheel-drive vehicle is more versatile and less prone to oversteer. If you live in a warm, dry climate and are a performance enthusiast, a rear-wheel-drive car might be right for you. A two-wheel-drive truck may also be the best choice if your primary concern is towing or hauling the maximum amount of weight.
Nothing beats the versatility of an all-wheel-drive vehicle when you want a mix of urban driving and rural performance. All-wheel-drive cars are jacks-of-all-trades and can weather harsh winter conditions when equipped with a good set of snow tires. That is why Subaru enjoys such popularity in the Northern US. All-wheel-drive cars also redistribute power automatically, so you don't have to worry about fumbling with controls and can focus on the road. They also have impressive resale values, particularly crossovers and SUVs, when compared to their two-wheel-drive counterparts.
For heavy high incline off-roading and trudging through unplowed roads, a four-wheel-drive car with a low gear range and high clearance provides the best mobility. Just remember to enable the right settings for the terrain, as failing to do so can damage your drivetrain.