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What Is Best For Winter Driving: RWD, FWD, AWD or 4WD?

Posted on December 2nd, 2010 in , | 8 Comments

What Is Best For Winter Driving:  RWD, FWD, AWD or 4WD?
By Eric Peters, Automotive Columnist

What’s the best set-up for winter-weather driving? Or just driving, generally? Is it rear-wheel-drive? Front-wheel-drive? All-wheel-drive? Or four-wheel-drive?

Here are some of the the pros and cons of each:

Four-wheel-drive (4WD)

This system is typically found in pick-up trucks and truck-based SUVs. Most 4WD systems work “part-time” — engine power goes only to the rear wheels until the driver (or, in the case of automatic systems, the onboard computer) engages the front axles. Typically, the power split front-to-rear is not adjustable. When in 4WD mode, the front wheels get 50 percent of the engine’s output and the rear wheels get the other 50 percent in a fixed-ratio split. Truck-based 4WD systems are also distinguished by the presence of a two-speed transfer case and 4WD Low range gearing, which is designed for very low-speed use in deep, unplowed snow (or off-road).

The upside: Truck-type 4WD systems are great for dealing with very heavy snow on unplowed roads and for off-road driving on muddy, uneven terrain; the Low range gearing makes it possible to crawl up steep inclines and slog through deep mud. Truck-type 4WD is great — even essential — for people who live in very rural areas or who must deal with heavy snow on unplowed country roads.

The downside: Truck-type 4WD systems usually operated in 2WD mode — with just the back wheels receiving engine power. When in 2WD mode, these vehicles often have less grip than a FWD car, which has the traction advantage of the drive wheels pulling (instead of pushing) the car and also because the weight of the engine and transmission are sitting on top of the driven wheels. In addition, 4WD systems are not designed to aid high-speed handling/traction on dry, paved roads. In fact, most 4WD systems come with warnings not to engage the 4WD on dry paved roads, because it may negatively affect handling and result in premature wear of the components.

Finally, a 4WD system adds a lot of extra weight to the vehicle, which in turn cuts down on fuel economy. While you may only need 4WD a few days out of the year, you’ll be paying for it every day by lugging around a couple hundred pounds of additional dead weight.

Not many people are aware of these significant everyday limitations of 4WD — even though the information is usually right there in the owner’s manual.

The bottom line: Buy a 4WD if you need a vehicle with serious off-road capability or have to travel often on rural (and unpaved) gravel or dirt roads – or if you live in an area subject to severe winters where it’s routine to have to drive through heavy snow on unplowed roads. Otherwise, it’s probably a money-waster.

Front-wheel-drive (FWD)

Most passenger cars being built today are front-wheel-drive — including “crossovers” that look sort of like SUVs but which are (usually) built on a car-based, FWD chassis.

The upside: FWD cars can actually be pretty tenacious in the snow because the weight of the engine/transaxle is sitting right on top of the drive wheels. FWD is vastly better in the snow than a rear-wheel-drive car. With a good set of all-season or snow tires, you will probably be able to make it to work unless the snow is really deep — in which case it’s the absence of ground clearance more than anything else that will cause you to get stuck. FWD is also more economical — both to buy “up front” and to operate over the life of the vehicle. You’re not paying extra when you buy the car — and you’re not paying every time you gas up to lug around equipment you only use a handful of times every year.

The downside: FWD cars are weight-biased toward the front, which is a built-in design limitation as far as handling/performance is concerned. Also, the wheels that propel the car must also steer the car, which isn’t optimal for high-speed driving/cornering. This is why most race cars and also high-performance cars are rear-wheel-drive. FWD is fundamentally an economy-oriented drivetrain layout designed to cut down on vehicle weight, simplify assembly and reduce manufacturing costs.

The bottom line: FWD is a good choice for the average driver who uses his vehicle to get from “a” to “b” and would like to have decent traction on those few days each winter when there’s some snow on the roads.

All-wheel-drive (AWD)

This is a system in which engine power can be sent to all four wheels — or even to individual wheels — as necessary to maintain traction. As recently as five or six years ago, only a few makes/models offered AWD systems; today, AWD is either standard or available optionally on many types of passenger cars, wagons, minivans and light-duty, car-based “crossovers.”

The upside: AWD provides excellent all-year/all-weather grip on snow-covered roads in winter and improves handling on dry (or wet) paved roads in summer. Unlike a truck-style 4WD system, AWD is optimized as much for use on smooth, paved surfaces as it is for use in snow (or even on unpaved gravel and dirt). High-performance AWD-equipped sports cars and sedans offer incredible dry-weather, on-road handling with superior wintry weather capability. Also, AWD systems do not require any driver involvement; power is automatically routed to the wheels with the most traction. And they can kick as much as 90-plus percent of the engine’s power to the front (or rear) wheels, as the traction situation dictates.

The downside: AWD is not designed for off-road use; there is no two-speed transfer case or 4WD Low range gearing. AWD can also add substantially to the purchase price of the vehicle — sometimes by as much as several thousand dollars. In some cars, AWD also usually adds significant weight to the car, which cuts both performance and fuel economy.

The bottom line: AWD is an excellent choice for the performance-minded driver who values dry-weather handling and high-speed grip in a corner as much as being able to get out of his driveway when it snows.

Rear-wheel-drive (RWD)

This was once the standard drivetrain layout of most passenger cars, especially domestic-brand models. The engine is up front — but power is sent to the rear wheels exclusively.

The upside: Rear-drive cars spread the weight of the engine, transmission and axle assemblies front to rear more evenly than nose-heavy FWD cars — and tend to be lighter (and cheaper to buy/maintain) than AWD-equipped cars. Rear-drive cars are also rugged and durable — which is why they are favored for police use/taxi duty. And finally, rear-drive allows for smoky burnouts — important to many performance car fans.

The downside: A RWD vehicle is not the hot ticket for snow driving — unless you enjoy fishtailing like a just-landed sea bass. Rear-drive (2WD) pick-ups are especially atrocious in snow; their light rear ends tend to break loose even on wet roads.

The bottom line: If you enjoy a good burnout every now and then, live in an area where winters are mild — and can handle dealing with some hassle on those few days each year when it does snow — then rear-drive will probably work for you.

Comments?
www.ericpetersautos.com


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8 Responses to “What Is Best For Winter Driving: RWD, FWD, AWD or 4WD?”

  1. [...] What Is Best For Winter Driving: RWD, FWD, AWD or 4WD? A very simple breakdown. Remove AdvertisementsSponsored Links ClubFrontier.orgAdvertisement  [...]

  2. 40yrsatthewheel says:

    There are a few things to consider. In the first place, the road departments use far too much salt, and far too often. Salting roads when the temperatures are below twenty-five degrees makes absolutely no sense when simply plowing the roads of cold dry snow would have the black top exposed instead of turning the whole matter into wet compressed slush or ice which is far slicker than dry snow.

    That said, I would agree that front wheel drive works well for the masses, particularly when snow tires are used at least on the front. However, when descending hills, it's quite easy to lose steering control while braking, particularly on curvy roads. I have also seen front wheel drive cars literally drive themselves off the road when drivers accelerate hard against torque steer, and, when they back off the tires bite and they find themselves on the shoulder or into the center meridian, or worse.

    The trick with rear wheel drive cars (no need to lug all that AWD hardware around) is to add enough trunk weight to achieve a slight rear bias through some sand bags, or those old weights you no longer put on the bar. These can be removed during summer months or if you plan to load the trunk with heavy luggage, and your mileage will be enhanced. Repair costs are far lower with rear wheel drive due to easier access to engine, transmission, etc., and there have been more rear wheel drive cars appearing in almost all of the brands.

    If you find yourself disagreeing with the salting theory, remember the last time it snowed. The TV announcers were announcing: "The plows are out, the salt trucks are out. The roads are treacherous." Does that sound like a success story? How long would you be employed if you produced similar results?

  3. jbt56 says:

    Sorry, Eric, but here I have to disagree. The best thing for Winter driving is COMMON SENSE. With a good helping of common sense, any vehicle can be safely operated in all weather. Keep in mind that many milions of drivers (and passengers) have survived over the past decades with only rear-drive cars available to them. FWD is only 'superior' for those who lack any shred of common sense or driving ability, while 'real' 4WD is, as you say, very suitable for rural applications.

    • schwinn8 says:

      I agree with you JBT… but I wouldn't call it "common sense"… as the joke goes, if it were so "common" we wouldn't need to talk about it. The point is, people who can't drive are the problem… not the car.

      Secondly, AWD doesn't kick over "as much as 90% engine power" to the front or rear wheels. Very few vehicles can actually do this, while most of the crap-AWD systems (Toyota, Nissan, Honda) can barely push 50/50 when necessary. For example, see http://www.awdwiki.com/article.html?inc=nis

      These are simply gimmick-based AWD systems for people who don't know any better. What's more, they won't get you out of trouble – I recall seeing a Murano AWD stuck in a small snowpile from the plow truck, spinning it's front wheel… because, you have to remember, the front diff is still OPEN, so it can't do anything to save you there. Most AWD systems have open front diffs.

      Although it's probably biased, this youtube video shows that not all AWD systems are alike, and there are big problems with the crap being fed to the ignorant masses: http://www.youtube.com/watch?v=2OzK-oRPCbs

      Lastly, although AWD is a nice feature, it can actually get you into MORE trouble than it's worth. This is because AWD will give these same clueless drivers a false sense of security when driving along, but when the car starts to fishtail, the driver often lets OFF the gas, which means the AWD system can't do its job, and the car ends up in a spin. I've seen it many times, as it's very easy to do. Again, lack of driver ability is the problem here.

      Bottom line, FWD is best for the people who can't drive (or can't be bothered to learn). The rest is for the people who have even a small amount of ability to understand the system.

      Incidentally, this lowest-common-denominator behavior is why we are being forced to have stability control on all cars in 2012. So sad, so lame, and so pointless… as it's just making the drivers dumber and dumber.

    • GeorgeC_ says:

      I'd have to disagree.
      A rear wheel drive vehicle with 55/45 weight distribution and an open differential (without hardware & software traction control) is going nowhere in snow.

      Unless you use chains (or a modern equivalent: AutoSock, Snobootz, GoClaws, EasyGrip, Put&Go, Biathlon, Softspike, 'next generation' snow chains)

    • schwinn8 says:

      Additional info. I was curious to see if there was a study done comparing accident rates between vehicle types (AWD vs others). I found one from Australia here: http://monash.edu/muarc/reports/Other/RACV%204WD%

      Now, I don't want to summarize the data for them, but I have always found that people driving AWD/4WD tend to drive with less "common sense" as jbt56 stated. The short story is that you really need to know HOW to drive properly with different drive wheels. Each one needs different actions in a skid… and too many people are pre-programmed to slow down and back off the gas when getting into a skid… this is the WRONG thing to do in an AWD vehicle, as it will CAUSE a spin.

      The bottom line is that AWD won't solve ANYTHING. In fact, it will make an inexperienced driver more dangerous, because the AWD will get the car moving faster, and with a false sense of security… when the reality is the car will skid just as easily as a FWD/RWD car when rounding a corner, for example. Of course, there's also the fact that ALL cars have 4WB (4 wheel braking) so these AWD people already going to fast are just going to get into more trouble.

      Thankfully, as I mentioned below, REAL AWD isn't what these Honda/Toyota/Nissan minivans and other "SUVs" have… so they can't get into too much more trouble. These people NEED less traction, to keep them out of trouble they can't handle.

      In the end, better driver training is what we need… for regular conditions and for adverse. Separating the driver from the road (via ABS, AWD, stability control, etc) will just make for more accidents as the drivers are even LESS experienced to deal with driving.

  4. TheNamesIsJames says:

    Great article! I'd add that all season tires are simply tires that aren't too bad in snow, where as winter and snow tires step the performance up to all new levels.

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