All Wheel Drive Vs. 4 Wheel Drive in Snow

There are actually two types of four- wheel drive: True four-wheel and full time four-wheel. In the first, all the wheels are turning at the same time because the transfer case redirects power to all four wheels. In other words, the front end and the rear end are driving at the same time. In traditional two-wheel drive the rear end would basically be turning and "pushing" the front end. In front wheel drive the front end would be turning,"pulling" the rear end.

With true four-wheel drive, the operator decides when they need the extra traction of all four wheels and manually (either by inside switch or outside wheel lugs) turns on the four- wheel-drive. When all four wheels are engaged the vehicle should not be driven on dry pavement. It is designed for snow or mud now. There are two settings for four- wheel drive: Low and high. High is for driving at speeds above 30 to 45 miles per hour on a highway. Low is for driving at slower speeds that need more traction, such as deep snow or mud on a back road--or sometimes your own driveway.

Some vehicles have what is called full time four- wheel drive. These vehicles have an additional set of gears in the transfer case, which allows it to be driven on hard surfaces such as a dry road.

All wheel drive is controlled by the vehicle's internal system. When the vehicle senses loss of traction it will switch from two-wheel drive into AWD, so it is considered a full time system. The other difference between all wheel and four- wheel- drive, is AWD wheels turn independently from one another. This makes it better on a hard surface or dry pavement. The power is split evenly between the front and rear axle. An AWD vehicle has the ability to increase traction no matter what condition the road is in. Some AWD vehicles allow the driver to choose a high or low mode.

Driving a four- wheel -drive vehicle or an AWD in the snow definitely gives an advantage as far as traction is concerned. While AWD is convenient, especially for those who drive in more urban settings, there are pitfalls. In four- wheel drive the amount of torque sent to the different axles has a set ratio, but in an AWD vehicle the system will send the torque to the wheel with the most traction. Sometimes it may send all the power to one axle only. In addition, AWD is definitely less fuel efficient as it is engaged all the time, as compared to four- wheel drive which is engaged only as needed. Cost is also an issue with AWD, as repairing the system is more complicated.

Which is better in snow? Both are equally good depending on what type of road conditions you drive. Choose your vehicle by the way you drive. If you are driving "off road" often, then a four- wheel drive will be better as the low setting gives more torque to all four wheels. For those who drive daily on snowy roads, the convenience of AWD may be preferable as it takes away the stress of knowing when to switch into four-wheel drive -- as long as you don't mind losing gas efficiency. When it gets right down to actual performance, all systems require the proper tires to provide good function. Without good tires and tire pressure, your four-wheel or AWD vehicle will not get proper torque. In fact, your AWD system can turn a worn tire into a "slippery" situation.

Having four-wheel -drive in any form does not mean you should drive fast or that you have the "God-like" vehicle. Power sent to four wheels, instead of two, only helps in starting out not cornering or stopping. With all four wheels turning, you also have four wheels which can suddenly stop. Sliding in this situation can sometimes be worse.

Regardless of which vehicle you choose for driving in snow, it is important to always think in terms of stopping, especially in an emergency situation involving the safety of other drivers. All the traction in the world will not help if you are driving too fast for the road conditions.