In the past, vehicles with four-wheel drive (4WD) capability were mainly limited to pick-up trucks and large SUVs. Fortunately, automakers mastered technology that offers an affordable alternative for smaller sedans and crossovers, making driving in hazardous conditions a safer experience: all-wheel drive (AWD).
Vehicles equipped with these systems send power to both the front and rear axles simultaneously. The result is an improved handling experience and better traction when navigating slippery roads. The robust performance makes 4WD and AWD automobiles more effective than standard two-wheel drive systems when driving in rain, snow, and ice.
Before you can make an educated decision on which system is right for your next vehicle purchase, you must learn the pros and cons of both systems and what makes them unique. So, what exactly is the difference?
The short answer is that AWD systems take the guesswork out of employing 4WD control by automatically engaging additional power or by maintaining it at all times. In contrast, most 4WD vehicles require human intervention in order to engage, whether through selector switches or manual locking hubs.
Read on to find out all you need to know about the two systems so you can find the vehicle that makes the most sense for you.
How AWD Works
In the auto industry, there are typically two forms of AWD systems available: full- and part-time. Full-time systems send power to the wheels continuously, ensuring enhanced stability whether you’re travelling in slippery conditions or on dry pavement. This setup relies on a network of centre differentials, viscous couplings, and multi-plate hydraulic clutches to ensure that power is distributed to any wheel that slips on one axle. The system automatically compensates for the compromised rotation with torque from the stable axle until the slipping is eliminated.
Part-time AWD systems include vehicles that are generally defaulted to operate in either front or rear-wheel drive until innovative sensors deem that road conditions require more traction. Rather than relying on a centre differential, part-time AWD vehicles use advanced electronically controlled software to delegate power between the front and rear axles. As the operator commutes, real-time information is communicated to the vehicle’s computer, determining when extra traction is necessary. The system automatically engages and then disengages (back to its default mode) once it detects that the driving environment has returned to normal.
How 4WD Works
As we already stated, the key difference between AWD and 4WD systems is that the latter generally require driver intervention. In the past, trucks were commonly equipped with manual locking hubs on the front wheels. To activate a truck’s 4WD capabilities, the operator had to physically leave the cabin and turn a dial to lock onto the axle and allow enhanced performance. While this technology did help drivers deal with slippery road conditions, it also required them to determine when torque would be demanded from all tires.
Today, most manufacturers include a switch within the interior that helps drivers quickly shift in and out of 4WD mode without leaving the vehicle. When this mode is engaged, the system locks the front and rear axles together and splits the torque 50:50. To achieve this even distribution, the system activates a transfer case connected to the transmission to ensure all the wheels are moving at the same speed. The outcome is better traction while off-roading on steep hills or travelling in slippery conditions.
Which is Better: AWD or 4WD?
While both systems have the same results, each offers its own advantages, depending on your driving style and the type of vehicle you want to purchase. If you’re interested in AWD’s benefits, your vehicle search will be limited to cars, minivans, and some crossovers. The specialized drivetrain of such a vehicle is an exceptional fit for drivers who stick to highways and suburban travel but don’t need the aggressive power of pick-up trucks used for off-roading.
The main advantage of AWD vehicles is the automatic engagement of all four wheels determined by the vehicle’s sensors and on-board computer. When the sensors are working correctly, the computer can have a faster reaction time to slippery conditions compared to human intervention. Since split-second decisions are common occurrences while driving, the assistance provided by this technology can not only instill confidence in drivers when road conditions are hazardous but can also be lifesaving.
4WD vehicles offer more control for operators by allowing them to engage different driving modes as their surroundings change. Since part-time functions are used on larger automobiles, such as trucks, drivers are granted substantial advantages in addition to increased traction. For instance, today’s 4WD pick-ups
- are exceptional haulers;
- boast impressive towing load capacities; and
- perform efficiently as daily drivers and workhorses.
Truck and SUV owners are better equipped for off-roading because the 4WD capabilities and higher ground clearance of these vehicles allow for accessibility to rough terrains, such as sandy, muddy, or rocky ground and steep hills.
The answer to which is better, AWD or 4WD, depends on your daily commute and what you’re seeking in a vehicle. If improved traction on busy roadways is your most significant concern, looking for an AWD vehicle would provide you with more options. However, if rugged work performance, towing, or driving on desolate backroads is on your checklist, a 4WD model is a more suitable choice.
What Are the Drawbacks of AWD and 4WD?
Most innovative automotive features come with disadvantages, and AWD and 4WD vehicles are no exception.
One of the most substantial drawbacks of both AWD and 4WD vehicles is the initial price tag. These intricate drivetrains require numerous sensors and parts as well as up-to-date technology to operate flawlessly. Unfortunately, these operating components translate to a higher sales price compared to similar models that are only front- or rear-wheel drive. The cost of ownership can also be higher when it comes to repairs, as some of the software in these vehicles may require specialized service and calibration when resolving an issue.
It’s vital to budget for expensive parts and labour costs when a vehicle is not working correctly or a problem is discovered during a regular maintenance appointment. Drivers should also consider that the additional weight used to support these systems will decrease stopping distance and require increased awareness for braking safely. Plus, the extra pounds and mechanical resistance employed to effectively distribute power to all four wheels will have a negative impact on the vehicle’s fuel economy.
Below, check out a few of the disadvantages tied to each system exclusively.
Because an AWD vehicle relies on high-tech software, drivers may adopt a false sense of security when travelling—even if a component has failed. Many computer systems will trigger a warning light on the dashboard when something is amiss, but if you don’t notice the alarm, you can find yourself driving in slippery conditions without the additional support of all-wheel mode.
Another common complaint regarding full-time AWD systems is the toll it takes on your tires. Since all the wheels are continuously working overtime, the tire tread won’t last as long as that found on two-wheel-drive vehicles.
While AWD vehicles can navigate in and out of AWD mode seamlessly full-time, 4WD mode should not be activated on dry pavement. Failure to disengage this system after travelling through slippery conditions can lead to severe damage to a critical component, as extra stress impacts the entire drivetrain. While the mechanically driven package isn’t as complex as AWD, expensive parts, such as the transfer case, differential gears, and front axles, are all at risk for an early demise after employing 4WD improperly.
When driving a 4WD vehicle, you must also be aware of impending conditions that may make the roadways hazardous. You should be familiar with how to engage the vehicle’s 4WD capabilities and ensure you can activate them before encountering slippery conditions. While most modern trucks and SUVs make the process easy, some systems require the vehicle to be in park, or they must be engaged at the wheel.
Conclusion and Recommendations
When deciding which system will best fit your needs, remember to consider the operating costs. Both drivetrains require regular maintenance and can incur expensive repair bills. Ask yourself if the enhanced performance is worth both the initial investment and the upkeep down the road. The good news is that maintaining most AWD or 4WD systems well will help to avoid catastrophic problems. With regular servicing, a certified mechanic can discover even minor issues before they impact your vehicle’s capabilities or your wallet.
There is no doubt that enhanced traction helps drivers travel through weather events like rain, snow, and ice. However, AWD and 4WD systems are not accident-proof for navigating various terrains. Drivers still have the responsibility of safely adapting to road conditions, and they must be aware of their own position in relation to other vehicles on roadways, driving defensively.
Keep in mind that neither system allows for safe driving if your vehicle’s tires are worn out. Ensure the tread is in good condition to promote better traction when driving on wet, snowy, or icy roads.
In short, both AWD and 4WD could come in handy during your commute, but these systems require driver responsibility to perform to their expectations. Remember to keep up you’re your vehicle maintenance, and become familiar with how your vehicle is supposed to operate so that you can quickly address and resolve any issues as soon as they arise.