Most cars and trucks made today have front wheel drive, but some have all-wheel drive (AWD) or four-wheel drive (4WD). While most consumers have a vague notion that all-wheel drive and four-wheel drive offer better performance in certain conditions, they might not understand the specific mechanics, benefits and drawbacks of front-wheel drive and all-wheel drive.
Front-wheel-drive vehicles apply the torque from the engine to the front wheels. This differs from rear-wheel drive, which distributes the driving power to the back wheels. Modern cars typically are equipped with front-wheel drive to provide better fuel efficiency and traction. By consolidating the transmission, engine and differential into the front of the car, the bulk of the weight is moved to the front of the vehicle, which gives tires a better grip on the road. The rear space can then be used for cargo or passengers, making front-wheel drive more suitable for passenger vehicles.
The differential in a vehicle is designed to allow both wheels to receive an equal amount of power while still allowing them to rotate at different speeds. This is to compensate for the different rotation rates when turning a corner. Because the inside tire covers less distance, it needs fewer rotations to make a turn than the outside tire (think of a rotating column in a marching band; the players near the inside of the line end up taking much smaller steps compared to those on the outside, who may have to run to keep up). By allowing the wheels to rotate at different rates, the differential vastly reduces the amount of wear on the tires.
When you are driving in slippery conditions---on snow, ice or mud---power would normally be distributed to the wheel that has the least amount of traction. Because of this, you would end up spinning one wheel while the other remained stationary. A limited-slip differential ensures that both wheels receive an equal distribution of power in such a situation while still allowing wheels to rotate at different rates while turning corners.
Four-Wheel Drive and All-Wheel Drive
A four-wheel-drive vehicle has power distributed to both the front and rear wheels. This power is equally distributed to the front and back axles, meaning that the differential will divert power to only one front wheel and one back wheel. However, a "locking differential" allows all the wheels to receive the same amount of driving power, which is good for off-road driving.
All-wheel drive differs from four-wheel drive because it allows power to be distributed among the wheels in any configuration. Rather than picking one of the front wheels and one of the back wheels, a vehicle with all-wheel drive can choose whichever wheels have the most traction, giving a driver optimum road grip. For example, an all-wheel-drive system could transfer power to only the front wheels or only the back wheels, whereas a four-wheel-drive car could only choose between the left and right side.
Four-wheel-drive and all-wheel-drive vehicles tend to get slightly less gas mileage than front-wheel-drive vehicles. This is due to the added weight from the multiple-wheel-drive components as well as the extra power required to engage more wheels.
What are the Benefits of All Wheel Drive?
All-wheel drive, which usually refers to vehicles with full-time four-wheel drive systems, can be an extremely useful feature in cars, trucks, and...
All Wheel Drive Vs. 4 Wheel Drive in Snow
When you live in a place that gets a lot of snow, or even moderate snow, the vehicle you choose is one...
4-Wheel Drive Vs. 2-Wheel Drive
Many different types of vehicles including pickup trucks, SUVs and even some cars boast about including four-wheel, or all-wheel, drive. This system...
Gas Mileage Difference between a V6 and 4-Cylinder
In addition to considering styles, prices and features, new vehicle shoppers often examine fuel efficiency. The government’s fuel economy website shows gas...
How Does a Front Wheel Drive Perform in the Snow?
With the best of cars, driving in snowy or icy conditions can be dangerous. Vehicles with front-wheel drive offer superior control in...
All Wheel Drive Vs. On-Demand 4 Wheel Drive
The terms All Wheel Drive (AWD) and Four Wheel Drive (4WD) indicate that vehicles with these designations are powered by all four...
Locking Differential Vs. 4 Wheel Drive
Vehicles that use four wheel drive can have various differentials, depending on the owner's desires and needed functions. One type of differential...
Does It Feel Different to Drive an AWD Car Vs. a FWD Car?
Driving front-wheel and all-wheel drive cars can be quite different experiences. All-wheel drive cars deliver power to all four wheels most of...
Front Wheel Drive vs. Rear Wheel Drive Advantages
Manufacturers, mechanics, car enthusiasts, and consumers, have long debated the rear-wheel drive versus front-wheel drive issue. Determining which vehicles tend to handle...
What Cadillacs Are Front Wheel Drive?
Cadillac is a vehicle marque owned by General Motors, and is one of the oldest car brands in the world. Upon being...
Difference in FWD & AWD
How many and which wheels drive your car is just one of the factors to consider when you're planning a purchase. If...