4x4 vs 4x2
Know the difference
4x4 versus 4x2 with a difflock?
A common fireside topic amongst bakkie drivers is whether a 4x4 is necessary, or if a 4x2 bakkie with a rear difflock will get the job done. After all, there's a lot more to a 4x4 than just an extra badge on the tailgate.
Firstly, let's look at the difference. A 4x4 bakkie such as a Toyota Hilux 4x4 has a part-time 4x4 system. In normal operation, it is in 4x2 (or two-wheel-drive) mode, and the rear wheels propel the vehicle. When the road surface has less traction, the driver can select 4x4, which engages the front wheels as well. If the terrain is really rough, the driver can select 4x4 Low Range, which allows the vehicle to travel slowly while under control and with lots of torque and traction available at all four wheels.
A 4x2 bakkie is a two-wheel-drive vehicle, just like a regular car. A 4x2 Hilux is driven by the rear wheels at all times. Under normal operation, the rear diff will be unlocked, which means that that the diff allows the two rear wheels to travel at different speeds, for cornering and better handling. (If the wheels travelled at the same speed around corners on a tar road, the inside wheel would have to slip and spin or the diff would be damaged. The inside wheel travels a shorter distance than the outside wheel.)
A rear difflock, as it sounds, locks the diff. This forces the two rear wheels to travel at the same speed all the time. The benefit of this is that if one wheel is in the air and one wheel is on the ground, or if one wheel is spinning in mud and the other wheel is on firm ground, the wheel with traction will push the vehicle forwards.
Obviously a 4x4 system will offer better traction on slippery or rough terrain – it's plain physics. But how often do you need this extra traction (or the added control and torque of low-range)?
If you intend to tackle 4x4 trails then an actual 4x4 is vital. If you are going to spend most of your time driving on tar or gravel roads, and maybe in sand, then a 4x2 with difflock should be adequate. One thing that you really should be aware of when driving with a rear difflock is that it does negatively affect the steering of a vehicle, because the rear wheels are turning at the same speed. It can be used to make sharp turns to avoid obstacles, and in sand you might be pushed out of the tracks at corners.
Something that isn't spoken about often is the use of 4x4 as a safety feature. On gravel roads, especially, using 4x4 in high range can be a useful safety tool, aiding in traction and playing a part in preventing accidents.
What we can't stress enough, though, is to practice with your vehicle (be it 4x4 or 4x2) so that you know its capabilities and its limitations. Another point is to engage 4x4 or difflock before you get stuck – it's much easier to prevent getting stuck than it is to recover a stuck vehicle.
Whether you buy a 4x4 Hilux or a 4x2 Hilux with difflock depends on what you want from your vehicle. There are some people who would rather have 4x4 and not need it, than not have it and need it. Others believe that if you don't need something, don't get it and rather focus on learning your limitations and staying within them.