4WD vs AWD: The Great DebateOct 20th, 2017
You’re in the showroom looking at a new car. You can’t quite decide what you want – maybe a midsize SUV, a pickup, or a sports sedan – and now you’re pouring over available options and configurations with the salesperson. Some extras are easy picks. Leather seats – check. A/C – check. Upgrades stereo – check. Then you stop… 4WD or AWD?
Aren’t those the same? Well, no. They are absolutely not the same, and you’d be surprised to learn how many relatively car-savvy individuals still think that. The truth is, there are unfathomable differences between an all-wheel drive drivetrain and a traditional 4X4 or 4-wheel-drive system. Each have their own unique strengths and uses – as well as cons – so knowing ahead of time will help you to make an educated decision on factual, real-world knowledge.
In this post, we’ll break down the inter-workings of each option, outline the differences, tell you where each shines, and where you can stand to benefit from selecting one of the two.
How Does It Work?
A typical AWD system, most often found in sports sedans and crossover utility vehicles, has evolved over the years into more of an -on-demand feature of modern drivetrains that is capable of sending power and therefore grip to the non-primary powered wheels – usually the rear wheels.
Basic systems operate by sending power through a power-splitting differential in the transmission and then through a prop shaft to a separate rear differential where the power is directed to each of the rear wheels. This is all done when an onboard computer recognizes that there is substantial primary drive wheel slippage, so the computer transfers power to the rear where wheels are not slipping. The power will remain as an all-wheel-drive unit until the same computer is able to detect that grip has been reestablished to the primary drive wheels.
Some AWD systems can also feature a 4-LOCK feature that acts similarly to a traditional 4WD system. Under 4-LOCK, a vehicle will secure a 50/50 power division between front and rear axles, locking power until a speed of about 5-10km/hr.
Four-wheel-drive vehicles are much simpler. This traditional drivetrain we often associate with pickup trucks and serious off-road capable SUVs is accomplished via an output shaft from the transmission that is led to a transfer case, where engine power is split evenly between the front and rear axles. The rear driveshaft ultimately turns a pinion inside the rear differential that turns each axle shaft, turning each wheel.
On most traditional and modern 4WD systems, the transfer case is divided into a 4-High or 4-Low gear, wherein a fork engages a drive chain that turns the front differential at the same speed as the rear driveshaft, linking and unifying torque and grip across all four wheels. The 4-Low setting is unique in that it allows the driver to multiply the transmission gearing to provide more power and greater control to the drive wheels at slower speeds for more useable torque and grip.
What’s the Difference?
The big differences between AWD and 4WD are the complexities involved in the operation of each system. AWD is often a computer-activated feature that assists when the driver is unknowingly slipping and sliding, making it a powerful safety-oriented tool that seduces most parents and people who commute in snow, sand, dirt, and wet weather conditions. AWD vehicles usually feature unassuming features as well, like regular road-going sized tires and moderate ground clearance appropriate for traversing through the odd snowdrift, over a tricky dirt road, or through a creek or two.
On the other hand, most 4WD and 4X4 systems are not aided by onboard computers and require the driver to have an intimate knowledge of the road condition and when to use each setting. The transfer case of a 4WD system will also require most vehicles be stopped before shifting from 2WD, unlike AWD systems which automatically adjust as you drive. For-wheel-drive vehicles are usually equipped with larger, more off-road savvy tires and boast ample ground clearance in anticipation of driving regularly through fields, up hills, and in off-road situations on a regular basis. They can also feature skid-plates and significant extra metal for protection under the chassis.
When Do They Shine?
All-wheel-drive systems are most at home during the daily commute. AWD vehicles like many crossover SUVs and sports sedans are perfectly suited to a rural commute or a climate that throws a multitude of road weather at the driver – from snow storms and heavy rain, to the odd dirt road and urban commute. They’re less capable off-road and because they invisibly switch back and forth between two and four wheel power, have the potential to save fuel costs if driven with modesty.
4X4’s are more at home in dedicated off-road, or work settings. Pickup trucks, for example, feature a dedicated four-wheel-drive transfer case for the implied types of driving and work the driver will be doing with the vehicle – whether that be construction, farm use, towing/hauling, or recreational off-roading.
Whichever you choose, both come in very handy if you live in an area where you deal with winter weather, or go camping with your family. The extra cost will be worth it even if it saves you once.
Both AWD and 4WD systems are sought after commodities these days as we see the continuing trend of more and more urban residents venturing into the countryside and taking up adventurous hobbies and pastimes with their families and friends. This means that over time, a vehicle with a functional AWD or 4WD system will maintain a decent resale value with the added protection and perceived safety features of the additional traction and capability.
Have a camping trailer? A boat? A yard work trailer? A 4WD or AWD truck or SUV will help you when towing from a wet, muddy, or snowy incline, and will reduce the likelihood of you getting stuck with the family during a remote camping trip.
Most people choose to purchase an AWD or 4WD vehicle when the live in an area that has potential to produce inclement weather. A vehicle with two-wheel-drive cannot accelerate at the same speed, or with the same sure-footedness as an all-wheel-drive or four-wheel-drive vehicle. Plans and simple.
False Sense of Security
It’s really easy to be sucked into a false sense of security when you have the added security of an AWD or 4WD system. Both systems provide added traction, increased stability, and help drivers feel safer in the snow and rain – but drivers with AWD or 4WD systems often get themselves in trouble more than their 2WD contemporaries because of a false sense of capability. Braking distances and handling will be the same in a 2WD vehicle. Always drive with caution.
Increased Fuel Consumption
4WD and AWD components usually decrease fuel economy slightly in most cars and trucks.
Whatever you decide to choose, any reputable and honest automaker, salesperson, or mechanic will tell you that a four-wheel-drive or all-wheel-drive system is always worth its salt if you’re able to save yourself even one call to a friend or a tow-truck to help you out of a jam. Plus, the added sense of safety – as long as it’s used with respect and caution – is a great way to boost your confidence on the road.