What is four-wheel drive?

What’s on this page?

• What is 4-wheel drive?
• How does 4WD work?
• Pros and cons of 4-wheel drive
• What’s the difference between AWD and 4WD?
• 4-wheel drive FAQs

Four-wheel drive is often cited as the best way of putting a car’s power down to the tarmac. It gives you more grip and more traction – usually, though tyres are very important too – and that means that you can use it to either head miles and miles off-road, or to have more useable performance when you’re staying on tarmac, as well as having a bigger safety net when the weather turns nasty. On this page, we’ll talk you through how four-wheel drive works, and what are its benefits and downsides.

What is 4-wheel drive?

Four-wheel drive, also known as 4×4, or 4wd, or 4-wheel drive, is a way of sending power from a car’s engine or its electric motors to all four wheels, balancing its power delivery and providing more grip and traction.

How does 4WD work?

Four-wheel drive works in two primary ways, depending on whether you’re talking about cars with engines, or electric cars.

In a car with an engine, normally power is sent to two wheels, either those at the front, or those at the rear, by means of a driveshaft running straight from the gearbox (that’s for front-wheel drive) or a propshaft leading to a differential, which splits the power between two driveshafts (that’s for rear-wheel drive).

Four-wheel drive basically adds those two systems together. So the power goes from the engine into the gearbox, and then through what’s known as a transfer case, which splits the power up between the front and rear wheels, and transmits that power through a series of differentials and drive shafts. The idea is that each wheel should get an equal amount of the power being produced by the engine (although this can of course be adjusted depending on the needs of the driver and the conditions in which you’re driving).

In an electric car, the setup is a bit simpler. Instead of a transfer case, or extra drive shafts, you simply add an extra electric motor. One motor drives the front wheels, and another drives the rear wheels, and the car’s on-board computers work out how to juggle the power coming from each motor.

Pros and cons of 4-wheel drive

Pros of 4-wheel drive

Better traction — a four-wheel drive car will be able to get going, and keep going, on slippery surfaces that a front-wheel drive or rear-wheel drive car might not be able to cope with.
Better power delivery — there’s little-to-no chance of spinning a wheel under acceleration with four-wheel drive.
More confidence — because a four-wheel drive car is less likely to slip and slide, the driver feels more confident in what they’re doing.

Cons of 4-wheel drive

Weight — cars with four-wheel drive tend to be heavier, and therefore less economical than their two-wheel drive cousins.
Complication — a four-wheel drive car involves lots of extra mechanical and electronic parts, which means there’s more to go wrong.
Cost — four-wheel drive cars tend to be more expensive.

What’s the difference between AWD and 4WD?

AWD, or All-Wheel Drive is generally what’s actually fitted to most cars. It means that power can be sent to all four wheels, but for the most part an AWD car will stick with either front-wheel drive or rear-wheel drive most of the time, only sending power to the other set of wheels when the car’s on-board computer detects that you need the extra traction or grip.

By contrast, 4WD, or four-wheel drive, is in theory designed to send power to all four wheels, all the time, and is designed for serious off-roading. However, the two terms are often used interchangeably and car companies don’t always make the distinction between one and the other.

4-wheel drive FAQs

Is all-wheel drive the same as 4-wheel drive?

Sort of — most car companies use the two terms pretty much interchangeably but if you want to get technical, all-wheel drive means power CAN be sent to all four wheels, but not always is; whereas 4-wheel drive, in theory, means that power is always sent to all four wheels.

Are all SUVs 4-wheel drive?

No, far from it. Actually most SUVs are two-wheel drive, most commonly front-wheel drive. Many offer the option of four-wheel drive, but it’s not usually until you get into the larger and more expensive models that four-wheel drive starts to become standard-fit.

Is 4-wheel drive good?

Yes, if you need it. Four-wheel drive is great for tackling rough terrain, if you have a chunky SUV, or it’s equally great for giving a low-slung performance car extra traction and grip, and giving you more confidence in tricky wet, or snowy, conditions. It’s still important to have good tyres, though!