If you’ve ever driven during the winter in Canada, you know how much of a difference the right drivetrain can make. If you’re thinking about getting a new vehicle this season, taking a closer look at your drivetrain options, especially all-wheel drive systems, may help you make your final decision.
Types of Drivetrains
The four most common types of drivetrains are front-wheel drive (FWD), rear-wheel drive (RWD), four-wheel drive (4WD), and all-wheel drive (AWD).
FWD
In FWD, the car’s engine powers the front two wheels to make the vehicle move. Of the four choices, FWD is typically the cheapest and most fuel-efficient because of how compact it is.
In North America, most vehicles have FWD as a standard system for most driving conditions and AWD for specific conditions.
RWD
RWD relies on the rear two wheels to move the car. Because of the powerful acceleration it offers, RWD is the most popular system for sports cars.
It’s also common for RWD standard vehicles to have an optional AWD mode, especially in pickup trucks and large SUVs.
4WD
With 4WD, the same amount of power is sent to the front and rear axles of the vehicle at the same time. This system is ideal if you frequently drive in difficult conditions.
4WD is available in part-time or full-time modes. In most cases, it’s paired with FWD or RWD and is meant to be activated by the driver for temporary use when off-roading or on very slippery roads in extreme weather.
All-Wheel Drive Systems Explained
How does AWD work? Like 4WD, AWD sends power to all four wheels. AWD can vary the amount of power sent to each axle, however, allowing the wheels to rotate at different speeds. A drive shaft that runs between the car’s axles allows the AWD system to adjust how much power is sent to which axle.
Most AWD systems will focus more power on the front two wheels. If an AWD system is described as 60/40, for example, it means 60% of power goes to the front wheels while the other 40% goes to the rear. This is the most common power ratio for AWD, but sportier models may put more emphasis on the rear wheels, while other systems will maintain a 50/50 distribution.
You can use AWD for everyday driving, light off-roading, and certain kinds of performance driving. It usually activates automatically with no input from the driver. It’s not ideal for intense off-roading or heavy-duty lifting (where 4WD excels).
AWD is typically available as a full-time or part-time system. Even within the same manufacturer, the design of an AWD system can vary between vehicles.
Full-Time AWD
Full-time AWD always uses all four wheels used to move the car. If the wheels on the front or rear axle start to spin, more power is sent in the other direction to balance things out.
Part-Time AWD
Part-time AWD is the more common version of this drivetrain. Part-time AWD is paired with vehicles that have FWD or RWD as a standard. In these cases, the vehicle will automatically switch to AWD from FWD when the front wheels spin or from RWD when the rear wheels spin. Part-time AWD is most common in SUVs and cross-utility vehicles.
Both full-time and part-time AWD systems require no action from the driver. In some vehicles, though, the driver can choose how much power is sent to which axle.
AWD in Electric Vehicles
Most electric vehicles (EVs) come with RWD, but they can be equipped with AWD, as well.
The main difference between AWD in an EV versus a gas-powered vehicle is that there’s no drive shaft connecting the two axles together to distribute torque.
EVs without AWD will have one motor, but those with AWD have two. Instead of relying on a drive shaft, an EV has one electric motor powering the front wheels and another electric motor powering the rear.
Pros & Cons of AWD
To help you decide if it’s right for you, check out this summary of the main pros and cons of AWD.
Pros
- Engages automatically with no input from the driver.
- Works on various road conditions.
- Increases control around corners.
Cons
- Tires may not last as long.
- Reduces fuel efficiency.
- Limits off-road capabilities.
- Costs more.
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