A car’s drivetrain, or the way a vehicle powers its wheels, can make a huge difference when it comes to driving in harsh weather conditions or on unpaved or rough terrain. But many of us still remain confused about the basic differences (and advantages and disadvantages) of 2-, 4-, and all-wheel drive vehicles. Check out the mysteries of the drivetrain and learn the difference between 2-, 4-, and all-wheel drive vehicles.

What is 2WD?

First off, 2-wheel drive (2WD) comes in 2 flavors: front- or rear-wheel drive.

Most cars sold today are front-wheel drive (FWD) vehicles, meaning the engine directly powers the front wheels of the car and does not deliver any power to the rear wheels. This design offers distinct advantages, accounting in part for its overwhelming popularity. For one, the engine weight at the front of the vehicle lends better traction to the front wheels in slippery conditions. Additionally, FWD vehicles tend to be roomier than their rear-wheel drive counterparts — without a driveshaft transferring torque to the rear wheels, the cabin floor can be flat.

On the other hand, rear-wheel drive (RWD) offers good traction on vehicles with heavy rear loads (like trucks) and can provide more balanced weight for better handling on performance vehicles.

What is 4WD?

A 4-wheel drive (4WD) vehicle has the ability to apply torque to all 4 wheels of a vehicle some of the time. Supplying equal torque to all 4 wheels provides greater traction, but can be problematic on ordinary roads. In normal driving conditions, for example, the 4 wheels of a vehicle need to turn at different speeds (like when you round a corner, the outer wheel has to travel a greater distance than the inner wheel). Differential gears allow the wheels to turn at different rates, making them safe to drive on roads, but with reduced traction. 4WD vehicles allow you to (either manually or electronically) lock the center differential, delivering equal torque to the front and rear axles. This offers outstanding traction on rough and slippery roads, but would cause damage to the drivetrain on ordinary asphalt.

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4WD vehicles also offer low gears with generously multiplied power for slowly climbing up steep slopes or over obstacles. These vehicles tend to have much higher clearance than 2WD vehicles to allow for driving on difficult terrain. The rugged nature of 4WD vehicles means that heavy-duty (emphasis on the heavy) components are used and you’ll very likely pay a penalty on gas mileage to drive one.

What is AWD?

Like 4WD vehicles, all-wheel drive vehicles are capable of delivering power to all 4 wheels some or all of the time. Generally, today’s AWD cars send power to all 4 wheels when slippage or rapid acceleration is detected. AWD vehicles vary in the level of torque they can apportion and how they operate, but typically the function is automatic and computerized. This makes AWD a better choice for drivers who may need some extra traction in snowy or gravelly conditions, but aren’t planning on doing recreational off-roading.

So which one is right for me?

If you live in a snowy area or travel frequently on dirt roads, or you routinely tow your boat up a slippery ramp and out of a lake, then a 4WD or AWD vehicle is probably no-brainer. But if you spend most of your time on dry, well-maintained roads, you might be better off renting an AWD vehicle for your once-a-year ski trip and buying a 2WD car for regular driving.

Also, keep in mind that the right tires make a huge difference. Some FWD vehicles with winter tires have outperformed AWD vehicles with all-season tires in snow driving tests, for example.

So, whatever type of drivetrain you choose, make sure you pair it with the right tires to get the best performance possible.

Now that you’ve unlocked the mysteries of your drivetrain, make sure you’ve got auto insurance you can rely on. Get a quote today.

Not available in all states. Policies underwritten by Esurance Insurance Company and its affiliates: San Francisco, CA

 

 

Safe and smart | Car safety

about Rebecca

Rebecca is a freelance copywriter and editor living in the SF Bay Area with her husband and two kids. She enjoys productively channeling her anxiety into safety-minded articles for home and garden, running with her robot trainer, and advocating on behalf of the Oxford comma.