(ISEECARS.COM) — If you’re browsing vehicles, you may notice some models come standard with front-wheel drive (FWD), but all-wheel drive (AWD) is available for a small upcharge.
In order to decide which option is best for you, it’s important to understand what these vehicle drivetrain types are and what the difference is between FWD and AWD.
Automakers and dealerships love to tout the all-weather capability of all-wheel drive and the additional confidence it inspires during inclement weather. But is AWD really necessary? Finding the right drivetrain option depends on your location and driving needs.
If you want a better sense of the major differences between the two systems, as well as their benefits and drawbacks, read on:
Front-Wheel Drive (FWD)
The first front-wheel drive cars were built before World War II, but it wasn’t until the 1980s that the design became mainstream. Now it underpins most sedans and crossover SUVs on the road today.
FWD is exactly what it sounds like: the front wheels act as the driven wheels, or the wheels that get the power from the engine. Before reaching the wheels, the power is first sent to a transaxle, which is a part that acts as a sort of combination transmission and differential. The transaxle ultimately routes the power to the two front wheels.
One reason why this design has become the preferred layout for modern cars is because it is inherently fuel efficient while offering more cost-effective packaging and superior space utilization. A front-drive car doesn’t need a longitudinal transmission, driveshaft, or rear differential, all of which are necessary for rear-wheel drive as well as some all-wheel drive cars. By eliminating these components you can have a flat interior floor and a lower cargo hold. The result is a roomier cabin, lighter weight and lower energy/drivetrain losses between the engine and driven wheels.
FWD is also a safer option than rear-wheel drive (RWD), the reason being its behavior at the limits of grip. If you lose control in a rear-drive car, it usually means the rear tires lost traction – in other words, more power was sent to the tires than they could handle. At that point the tires lose their grip and start sliding. During such a slide the rear end gets light and can come around quickly, resulting in oversteer and a full 360-degree spin, if you’re not careful, though the standard traction control on modern cars can sometimes prevent this.
This scenario is far less likely with front-wheel drive. In most instances, a front-drive car that enters a corner too fast succumbs to understeer – a condition in which the car turns less than you’d like. When it happens it feels like you’re plowing into a corner. For anyone who isn’t a race car driver, this is the easier situation to deal with, as there’s no risk that the rear end will snap around and send you spinning.
Compared to all-wheel drive, a front-wheel drive vehicle will return better fuel economy in just about every instance. With less heavy componentry to tote around and fewer mechanical parts to send power through, the front-drive car will usually eke out an extra one or two miles per gallon compared to its equivalent all-wheel drive model.
If there are any faults with front-wheel drive, it’s with issues concerning grip and performance. Take the dreaded phenomenon of torque steer, for instance. Ever mash the throttle of a front-wheel-drive car, only to feel the steering wheel seemingly get yanked out of your hands as the car makes a beeline for the edge of the road? That’s torque steer. It can plague high-performance front-drive cars and is the primary reason for why there’s relatively few 300-plus horsepower front-drive cars on the road.
Another reason high-performance and front-wheel drive don’t play well together is handling characteristics. That safer handling we mentioned earlier? Great for your mainstream crossover, but not so ideal for a sports car. More neutral handling is found on all-wheel drive and rear-wheel drive cars.
And a word about grip. Yes, it’s been said time and again that front-wheel drive is superior to rear-wheel drive in the snow and in slippery conditions, and this is true. But that doesn’t mean front-drive is totally unflappable. You can certainly get a front-drive car to spin its tires in an unplowed parking lot, even with the weight of the motor pushing down on the front tires. A FWD car will not offer as much grip or feel as sure-footed in the snow as an all-wheel drive car.
All-Wheel Drive (AWD)
Not too long ago, AWD was not much more than a curiosity, but today many buyers deem it an indispensable option when ordering up their new car. Underscoring this is that more and more new vehicles now offer it as an option, ranging from muscle cars like the Dodge Challenger to compact cars such as the Mazda 3.
Most sedans and crossovers that are running AWD use what’s called a part-time system; this means that the all-wheel drive only kicks in when necessary. The rest of the time the system sends all the power to the front wheels in most cases (or sometimes the rear wheels, as in the case of the Dodge Challenger). If the car senses that the front tires are spinning or slipping, it prompts the dormant rear wheels to get to work.
Some AWD options, like that found in Subaru models, use a full-time AWD system. As the name implies, power is always sent to all four wheels regardless of conditions. In times when weather conditions get nasty, the system may alter the power distribution between the four wheels. Full-time AWD is also found on performance cars; the Nissan GT-R, for instance, uses such a system to achieve its sub-3-second 0-60 mph time.
Be it a full-time or part-time system, better traction is the calling card of any AWD vehicle. It’s easier than it looks to get a two-wheel drive car in a situation where both driven wheels are spinning to no avail. That won’t be so quick to happen with an AWD vehicle; the engine powers both the front and rear axles, and odds are one of them has some grip to work with. This significantly lessens – though doesn’t eliminate – the chance of getting stuck somewhere or sliding out of control.
Out on the road, an all-wheel drive car will also have better grip during cornering, be it wet or dry conditions. And it’s always useful on an off-road trail, where rutted forest service roads or knotty two-tracks can make for some dicey approaches to the trailhead.
If there’s a major downside to all-wheel drive, it’s cost. When you initially purchase a new AWD car you should expect to spend at least $2,000 more than if you had bought an equivalent front-drive model. And as you drive it you’ll spend more on fuel, too, as the additional hardware necessary to drive all four wheels makes for a heavier car and creates additional driveline losses.
Some of the total ownership expense may be recouped at trade-in time, though; resale value is better for AWD vs. FWD vehicles.
One of the unfortunate side effects of AWD is the sense of false confidence it can provide. Yes, it can help get you rolling from a stop during bad weather. But it will not let you stop any faster. It’s easy to get goaded into a false security as you trundle down an unplowed road in your AWD-equipped Honda CR-V or Toyota RAV4, but if you have to start braking you’ll be no better off than anyone else on the road, whether they have AWD or not.
Also, don’t confuse AWD with four-wheel drive vehicles. Sometimes people use the terminology interchangeably, but there are major differences between the two systems: don’t expect to follow a Jeep Wrangler into the mountains with your Subaru Forester. AWD cars can only handle light-duty off-road pursuits, as they are lighter and lower than vehicles with four-wheel drive systems found in more rugged SUVs and pickup trucks. If you plan on doing regular off-roading, a 4wd system will better suit your needs.
Other Drive Types: Four-Wheel Drive and Rear-Wheel Drive
Four-Wheel Drive (4WD)
Although both 4WD and AWD systems send power to all four wheels, there’s a distinct difference between the two. That difference is what’s called a transfer case – a gearbox containing another set of gears that’s located alongside the normal transmission. This secondary gearbox essentially allows for a different set of gear ratios. These alternative ratios are designed to provide gearing for extreme conditions, such as driving in heavy mud, sand, or snow.
This is why four-wheel drive vehicles have a 4-hi and 4-lo selector, which refers to the high and low gear ranges. Four-wheel drive can also decouple the front axle completely in the 2-hi setting, which is the recommended setting for ordinary driving. Vehicles so equipped have what’s known as part-time four-wheel drive – four-wheel drive when you need it, and rear-wheel drive for all other instances. This is better for fuel economy and lower drivetrain wear and tear. A full-time four-wheel drive system only offers 4-hi and 4-lo; there is no option to disconnect the front axle completely.
All this flexibility is what makes four-wheel drive so potent off-road. With its transfer case and low-range gearset, 4WD vehicles can get through nearly any terrain, especially if they’re running dedicated mud or all-terrain tires. There’s serious capability in four-wheel drive rigs; it’s why Toyota 4Runners and Jeep Wranglers are such favorites with the off-roading crowd.
Where four-wheel drive suffers is in day-to-day livability. Bad gas mileage, long braking distances, ponderous handling, and a generally unrefined driving experience have long been common complaints among four-wheel drive vehicles, though constant refinement has substantially reduced these traits in modern 4WD vehicles (To learn more about the differences between Four-Wheel Drive (4WD) vs. All-Wheel Drive (AWD), refer to our handy guide.)
Rear-Wheel Drive (RWD)
Rear-wheel drive is the simplest of all the drivetrains. Carmakers just drop an engine under the hood, affix a transmission behind it, and from there add a simple rotating driveshaft to the rear axle to power the rear wheels.
In most situations, rear-drive doesn’t feel that much different than front-drive, especially during calm and dry conditions. Where rear-drive struggles – literally – is during inclement weather. This is due to weight and physics. With RWD cars, the driven wheels are, of course, the rear pair, located under the trunk or truck bed. Unless you’re loaded up the cargo area, this is nothing more than an empty cavernous space. That empty space doesn’t provide much mass to push down on the rear wheels.
This is quite the opposite from the front of the car, which is weighed down with the engine. Because there’s comparatively little weight over the rear wheels, traction is at a premium. Without any substantial weight pushing down on the rear end, It’s easier to spin the rear tires when you jab at the throttle during slippery conditions.
To mitigate these winter traction issues, many owners of rear-drive cars throw sandbags in their trunk. You can also purchase chains or studded snow tires to get better grip.
A particularly notable attribute of rear-drive is its handling tendencies. Generally a rear-driver offers the best handling from a performance-minded standpoint, but it also requires the most finesse to drive well without error. If you apply too much gas, you can overwhelm the rear tires, lose control, and find yourself in the spinning situation we noted earlier.
Because of its limitations during snowy or icy conditions and its tendency to be difficult to correct if control is lost, rear-drive is largely confined to performance cars. But for those who care deeply about handling, dynamics, and other more technical aspects of driving, rear-drive remains the standard.
Rear-drive is also the best drivetrain for anyone planning on towing. If you look at the tow rating charts for any full-size truck, for instance, you’ll see that the highest-rated towing combo always occurs in a RWD model, no matter the bed length, cab style, or powertrain. (To learn more about RWD vehicles, check out our handy guide for more details on the differences between RWD and FWD.)
The Bottom Line
Front-wheel drive is cheaper to buy and cheaper to run, but it doesn’t offer the peace of mind that an all-wheel drive system provides. AWD, on the other hand, has improved traction and is better in winter weather but costs more money, both upfront and throughout ownership. So which is better?
As always, the answer depends, particularly with where you live. A buyer in Duluth, MN with regular and heavy snowfall would benefit more from an all-wheel drive vehicle than a buyer in Atlanta, GA. Generally, the demarcation point where all-wheel drive is not really needed lies along the southern edge of the snow belt.
Yet that doesn’t mean you must buy AWD if you live in a place where snow and ice make a yearly appearance. If you live up north but really don’t find yourself ever leaving the pavement, a set of winter tires is an excellent alternative. In fact, a front-drive car with four winter tires will be better in most winter road conditions than an all-wheel drive car running a set of all-season tires. And if you live in an area that regularly has light snow, front-wheel drive will likely be sufficient.
That said, those who live on dirt roads, mountainous areas, or other remote, terrain-challenged places will want the extra grip of all-wheel drive. There you’ll want all the grip you can get, and a set of snow tires on a four-wheel drive car might not cut it.
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(Information from iSeeCars.com via the Nexstar Media Wire)