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The Most Efficient Drive Train in Winter Snow and Ice
For efficient winter driving, which is best: RWD, FWD, AWD, or 4WD? The efficiency and winter driving ability of each is a balance that should be considered before purchasing a new vehicle.
The efficiency of your vehicle is determined not only by how economical its fuel consumption is, but also by its ability to be used in all weather. If you live in the colder north, your vehicle needs may be very different than they would be were you to live in a warmer climate.
So let's explore the various drive trains (front wheel, rear wheel, all wheel, and four wheel drive) and how they affect both vehicle efficiency and winter weather driving.
We will assume that your vehicle uses fuel (gasoline, diesel, natural gas, or hybrid) and is not a battery electric vehicle (BEV or all-electric car). Battery electrics can come in any of these four drive train configurations, but have different efficiency measurements in terms of energy usage. Since they are not yet commonplace, we will not include them here.
FWD and RWD
These are the most-used configurations for most passenger vehicles. Front wheel drive (FWD) is the most prevalent in today's cars while rear wheel drive (RWD) is common in larger vehicles such as trucks and SUVs as well as in older cars.
FWD has many advantages in terms of efficiency over RWD vehicles. This is why is it more often used today. Its main advantage is weight distribution. With the engine being at the front of the car, this puts the main weight of the car on the front tires, giving them better traction if they are also the tires that move the car forward.
RWD has advantages in some applications, such as pickup trucks, because in these vehicles, much of the weight is more likely to be at the rear (in the cargo area) than at the front. RWD, however, has another disadvantage to FWD: power loss due to longer linkages. Because the power must be transferred from the engine at front to the wheels at the rear of the vehicle, mechanics must be used to move the energy. This reduces efficiency since any mechanics will involve power loss through those linkages.
- FWD has a definite advantage in winter weather because of its superior weight distribution towards the drive wheels of the vehicle. This coupled with the fact that most FWD vehicles are lower to the ground than are their RWD counterparts, gives better handling capabilities in adverse conditions.
- Neither FWD or RWD is better in deep snow or similar conditions than is having power going to all the wheels on the vehicle. RWD is decidedly inferior to all other drive trains in adverse weather conditions of almost all types, in fact, unless weight is artificially (outside of the vehicle's factory condition) added to the drive tires - a condition which inherently reduces fuel efficiency.
AWD and 4WD
Many crossovers and SUVs now feature all wheel drive (AWD) and many trucks and SUVs feature four wheel drive (4WD). The two are basically the same, allowing power from the engine to turn all four tires of the vehicle. The major difference between AWD and 4WD is that the latter is selectable either by the driver or by the vehicle's computer.
Normally, a 4WD vehicle will be a RWD until the operator or the vehicle's on-board computer select to go into four wheel drive mode. In an AWD drive train, however, all four tires are always being powered by the drive train with no exceptions.
Both systems have similar advantages in extremely adverse conditions, since all four wheels can vie for traction at all times (assuming 4WD is switched on). The major disadvantage of both systems is loss in overall fuel efficiency under non-adverse conditions. AWD is slightly more efficient in everyday driving than is 4WD, but both are much less fuel efficient than are FWD and RWD vehicles.
- Most AWD and 4WD vehicles have higher clearance and thus a better ability to get through un-plowed snow. Both also have generally superior traction in snow, ice, and extremely heavy rain than do their two wheel driven counterparts.
- Fuel efficiency is the major down side to AWD and 4WD systems. In most cases, they suffer a 30% or higher fuel consumption rate over their two wheel drive equals. This is not insignificant, taking a 2WD pickup capable of 25mpg down to 17.5mpg or lower.
Only a very few people living in North America really need AWD or 4WD systems in their everyday vehicle. Nearly all roads in America are paved and most are well-maintained during winter except in the most adverse of weather - which is often fleeting, causing less than a 24-hour delay.
For most of us, a FWD vehicle will accomplish 99% of our driving needs and will be much more efficient in terms of both fuel and weather handling than will other options.
If you do live in an area where snow, ice, and heavy rains are fairly common, consider a newer AWD vehicle rather than 4WD. Newer AWD systems (starting at around 2005) are tuned for road driving, rather than off-road as are most 4WD systems, and use power distribution to maximize efficiency in good driving conditions. This makes many of the newer AWD systems more fuel efficient than 4WD - especially when you consider that AWD is available in cars and smaller vehicles whereas 4WD is almost exclusive to truck-based vehicles.
In terms of sticker price, you will pay much less for the FWD vehicle because it is both more common and easier to manufacture than are the other drivetrain options. Of the four options, AWD is often the most expensive because of the more complex electronics and control systems required for this drive train.
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