There was a time when all-wheel drive offerings were rare in the auto industry. Today, it has become the norm, with carmakers offering this technology extensively and touting it as the eighth wonder of the world.
Reactive and permanent systems are the most common.
Some all-wheel drive systems are electrically controlled.
A 4×4 system is a whole different beast.
Driving an all-wheel-drive vehicle is indeed more reassuring in slippery conditions, but the driver’s behavior remains the ultimate measure of safety.
Nevertheless, there are different types of all-wheel drive systems on the market, which can make it confusing for buyers. What do you actually need?
The different approaches
Each manufacturer has its own philosophy, and different types of vehicles require specific devices. Broadly speaking, we could divide the systems into four main groups. There are reactive systems, permanent systems, traditional 4x4s, and electrically controlled systems, which are a new reality across the industry with EVs.
In this first of two articles, we will focus on the first two types: reactive systems and permanent all-wheel drive systems. These are the two most common types on the market.
Reactive systems
As the name implies, a reactive system responds to a given situation. Its operation is simple. As a general rule, during everyday driving on dry roads, power is sent to only two wheels, often the front ones. When the system detects a loss of traction, it transfers torque to the wheels that need it most.
The advantage of this configuration is that fuel consumption is lower during everyday driving because the vehicle operates in two-wheel-drive mode. If you’re not looking for performance or live in an area with less snow, cars with this type of AWD (All-Wheel-Drive) will meet your needs.
Permanent systems
Here, too, the name says it all, as we have a system that is always active. In this case, a percentage of torque is always sent to all four wheels, maximizing traction at all times. For those who like to drive more aggressively, the system is constantly in attack mode for a more reassuring experience. For those who live where snow is a daily occurrence, where slushy, icy roads are the norm rather than the exception, you should prioritize vehicles equipped with this type of drivetrain.
Depending on the manufacturer, power distribution between the front and rear axles varies. Some will adopt a 50/50 split, while others will take an approach where the rear receives 60% or 70% of the torque, for example, to give the drive a sportier feel.
And with some vehicles, it goes even further, with targeted distribution between the left and right rear wheels. We will have a chance to delve into this topic later.
As for not, there it is for the two main types of all-wheel drive systems.
Coming soon: a look at two other drivetrain types: 4×4 systems and electric configurations.
