October 23, 2019

All Wheel Drive And 4 Wheel drive

What is All Wheel Drive and how is it different from 4 Wheel Drive?

With cars getting smarter, not only have they shed weight, they have become more efficient without losing power, they also have added some amazing new technologies which are not so talked about, at least not as much as they should be, which has led to some confusion with people. I will try to dwell on one such topic.

What are the difference between All Wheel Drive (AWD), Two Wheel Drive (TWD) and 4 Wheel drive (4WD). Without going into the technical aspects of these, which might sound gibberish for quite a few like me, this is a simple benefit led explanation attempted here.

Two Wheel Drive (2WD) – This is the common drive that majority of the sedans & compact crossovers have. These could be rear wheel drive or front wheel drive where the power from the engine is delivered only to either the front wheels or the rear wheels as the case may be. The other two wheels have no traction of their own. 2WDs are usually driven within the city on ‘black tops’. These provide good efficiency as only two wheels are powered. These can have small engine size starting under 1-liter engines as well as fuel guzzlers.

4 Wheel drive (4WD) – also known as the 4×4 vehicles, these are usually found in Sports Utility Vehicles (SUV) which are used of off road driving where all the four wheel are delivered with power and hence if you experience a terrain where the grip is not available, all the four wheels provide traction to overcome the situation. I would like to further segment these into two kinds; the hardcore 4x4s & the SUVs. 4x4s like the Landcruiser, Patrol, Pajero & certain Jeep variants to name a few, can be driven into almost any kind of terrain and the SUVs which might have a 4×4 drive but not enough power & ground clearance needed to go on an off-road adventure. Of course the driver skills are critical to maneuver on these terrains apart from the machine itself. You might have the best 4×4 but that does not mean you can scale any terrain if devoid of driving skills. I have seen drivers who with a passenger van, take on some serious off-roading without the vehicle having any 4×4 capabilities. e.g. The vans used for Animal Safaris in Kenya which have very small modifications to their axel and shock absorbers. 4x4s are low on efficiency and usually have large engines to carry the heavy weight of the cars as well as to have enough power to conquer off-road terrains. In the case of some 4x4s, there are levers or switches to move from 4×2 to 4×4, which has to be manually engaged or dis-engaged.

All Wheel Drive (AWD) – This is an interesting technology given that it is the most intelligent of the three. It becomes a 2WD when driving on city roads and automatically changes to 4WD when the terrain changes. Power is provided to all the 4 wheels individually, which means the onboard chip decides when to release more power to which wheel depending upon the traction required. There are no switches or levers. The AWD is permanently engaged and this leaves a confusion that this may result in lower fuel efficiency, which is not true.

Some of the top luxury and niche brand use this technology, which provides superior drive and control to the car. Audi, Subaru, Mazda, are some of the brands that use this technology and it is more preferred on crossover vehicles due to its adaptability. These are more fuel-efficient without compromising on the traction required when needed. In fact Subaru range of cars across their sedans as well as crossovers have AWD along with the unique Boxer engine, which contributes to its drive control. (more on Boxer at a later stage).

The Crossover segment is slowly expanding its wings and range from small, mid and big crossovers that give the driving feel of a SUV (the ease of getting in & out, higher stance) and also the comfort of a sedan. This segment is the fastest growing one and the Big, bulky 4x4s are contracting globally except some markets like the Middle East where fuel is still not very expensive. The crossover segment is also expected to spread its wing towards the sedan side and convert a few.