This is a question that is easily answered by 4×4 enthusiasts and product planners working for car manufacturers who sell SUV’s, pickup trucks and some interesting all wheel driven station-wagons. However, for the average car buyer this difference can be confusing and many still think it’s the same thing.
Let us explain
Both 4-wheel drive (4WD) and All-wheel drive (AWD) distribute power to all four wheels of a standard vehicle, as opposed to the standard front or rear-wheel drive of 2-wheel drive (2WD) vehicles. If you live in an area of the country (like Borneo) where you will be driving in mud, red earth, or gravel roads, the added power of either system is valuable and very needed. However, many vehicle buyers still don’t know the difference between the two.
In attempting to answer what’s the difference between 4WD and AWD, start with part-time 4WD. This is the basic 4WD setup offered by many vehicles; it includes a switch that alternates between 2WD and full-power 4WD. As long as the 4WD setting is avoided on dry pavement, excessive mechanical wear can be avoided. Some vehicles in this class have a simple 2WD/4WD toggle, and some have added options like 4WD High and 4WD Low (the latter of which should only be used in extreme off-road scenarios). Newer part-time 4WD vehicles allow the driver to shift from 2WD to 4WD High while the car is moving but must be at a complete stop before moving from 2WD to 4WD Low. Older part-time 4WD vehicles must be stopped before any such shift can occur.
If you only need 4WD on occasion, then part-time 4WD is for you. Frequent changes in driving conditions that would necessitate a constant switch between 2WD and 4WD are both inconvenient for the driver and add wear and tear on the drive train.
This is a more advanced form of 4WD that can be left on without placing undue strain on the drive train. High and Low settings are available, as well as an automatic 4WD. Shifting from High to Low while in 4WD will require that the vehicle be at a complete stop (with most vehicles). Those drivers who drive under adverse situations more often can avoid the tedious 2WD/4WD switching and go with this full-time 4WD option.
All-wheel drive sends power to all wheels of the vehicle in a similar fashion to four-wheel drive vehicles, but a 2WD switch is typically not present. On a slippery road, AWD locks the vehicle’s axles and automatically feeds power to all wheels. Most AWD vehicles are great for slippery roadway conditions, but are not intended for rugged off-road excursions. Certain AWD vehicles such as the Subaru Forester do offer a low-gear AWD setting that allows for tougher roads, however. In general, AWD doesn’t add much weight to a car and is great for all weather situations like we are having this last week in Klang Valley.
Which is safer: 4WD or AWD?
Both versions off road handling tend to maximize traction over a 2WD, but it does not mean 4WD and AWD are automatically safer. Drivers should keep in mind that while 4WD and AWD help acceleration, they do not help with cornering and braking. On wet, water logged roads, it matters little whether you have a 4WD, AWD or 2WD vehicle when it comes to maneuvering and stopping. Using the right set of tires, having good brakes and a good working suspension are more important in that case.