Any car has several mechanical components that work together to help move the car forward. The most important of them is the engine. It generates all the power needed by the car in order to move ahead. Then comes the transmission. It is the transmission that puts the power from the engine down to the wheels.
Speaking of powering the wheels, the transmission channels the engine’s output to either the front two wheels, rear two wheels or all the wheels at once, depending on the configuration. This brings to the other most important mechanical component of a car, the drivetrain or drive type. It is this configuration that contributes majorly towards aspects like how well the car accelerates, how fuel-efficient it is and how well it can handle under different driving scenarios.
Before getting into the details of how a drivetrain contributes to these aspects, let us first try to understand what each of the different drive types are, and how they function.
As the name suggests, a front-wheel drivetrain is one where the engine sends power directly to the front wheels. This drivetrain is the least complex to design and also the cheapest. The main reason behind it is the fact that most cars have their engines mounted at the front. So it is relatively easy to connect power from them to the front wheels. Utilitarian sedans like the Hyundai Elantra and Honda Accord are some of the most successful examples of front-wheel driven vehicles.
What are the Advantages and Disadvantages of Front-Wheel-Drive cars?
As already mentioned, the FWD configuration is very easy to design and also cheap. So being economical is clearly one of its major upsides. There is, however, more to it than just that. Let us look at it various advantages first:
- Fuel efficiency - Besides being cheap, another major purpose that the FWD configuration serves is that of being extremely fuel-efficient. As the engine is directly placed over the front axle, lesser energy is required to channel power to the front wheels. This reduces fuel consumption.
- Traction - Another major attraction of the front-wheel-drive type is the traction it provides over wet or slippery surfaces. As the majority of the car's weight is upfront, there are very few chances of it slipping away or “fishtailing”. The car remains planted and returns better control.
Then again, the system is not without flaws. Yes, it serves great functionality but that takes a toll on performance. Let us take a look at the disadvantages of the front-wheel drivetrain:
- Acceleration - One of the major challenges of the FWD configuration is what is commonly known as torque steer. Under heavy acceleration, uneven power distribution to either of the front wheels can cause the car to steer in one direction, resulting in loss of control.
- Handling - As all the components are placed upfront, the wheels have very little room left to turn as sharply. As a result, the front-wheel driven cars usually have a wider turning radius. This takes away much of the ease of steering the car around.
- Wear and Tear - The majority of the weight is placed on the front wheels, who also have to undertake steering, acceleration and braking inputs. Together all these factors contribute towards a shorter life-span of the front wheels, resulting in more frequent replacements.
This brings to our next contender, the rear-wheel drivetrain. Let us look into its details in order to fully understand which one is the better of the two.
This drive type is the exact opposite of the front-wheel drivetrain. True to its name, the engine sends power all the way to the rear end of the vehicle to set the rear-two wheels in motion. The mechanism is complete with a long driveshaft connected to a separate differential. The demonic Dodge Challenger and the European muscle of cars, the BMW M2 Competition, are some of the most renowned RWD cars.
What are the advantages and disadvantages of the Rear-wheel drivetrain?
Yes, the RWD configuration is a lot more complex but it serves a different purpose altogether, and better performance is the core of this drive type. Other advantages of the rear-wheel-drive unit are as follows:
- Acceleration - A rear-wheel driven car accelerates a lot better than its front-wheel driven counterparts. As you push the accelerator, the weight of the car is transferred to the back, resulting in maximum acceleration under optimum condition.
- Handling - Besides more punchy acceleration, the rear-wheel drivetrain also accounts for better handling by eliminating the issue of torque steer. As the front wheels only have to focus on steering the car, the effort reduces significantly.
However, even the application of the rear-wheel drivetrain is also limited. It is not the be-all of drive type applications. The major disadvantages of it include:
- Fuel efficiency - The use of the separate differential to turn power from the driveshaft to the rear wheels requires the engine to consume that much extra fuel. So the RWD unit is naturally not very economical when it comes to the consumption of fuel.
- Cabin space - In order to accommodate the driveshaft, a hump is created along the entire length of the cabin. This compromises the availability of space inside and the overall practicality of the vehicle.
- Traction - Sure, a rear-wheel-drive car handles better but only as long as the surface is dry. Under not so optimum road conditions, the vehicles usually tend to lose traction and slip sideways. This results from the fact that all the weight is upfront but power is sent to the back. So there’s hardly any weight to keep the rear-end from slipping away.
After looking at the two drive types separately, it turns out that both serve entirely different purposes. Though none is a complete package. So the decision of which is the better of the two clearly sits on your driving needs and what do you expect out of your car. If it is more efficiency you want, the FWD configuration is the one for you. In case you are inclined towards the thrill of driving, the RWD unit is the way to go.
Although, it is hard to determine the clear winner. Then again, what if there was one drive type to combine the benefits of both the front-wheel and rear-wheel drive units while at the same time eliminating their shortcomings? Well, of course, there is. It is what is known to us as the 4-wheel and all-wheel drivetrain. Now, don’t get confused between the do. The underlying technicality between them is very similar but still, they are hemispheres apart.
The four-wheel-drive unit combines the advantages of the aforementioned drive types by offering better handling, traction, and even performance. It becomes extremely handy in inclement weather conditions and is definitely the sweet spot between the form of the RWD unit and the functionality of the FWD one. The Jeep Wrangler is one of the most coveted 4-wheel driven vehicles of current times.
The all-wheel drivetrain configuration, much like the 4-wheel unit, has the capability of powering all the wheels. It judiciously transmits power to that wheel that has the most traction, thereby, resulting in much better control over varying driving scenarios. Audi’s Quattro, Mercedes-Benz’s 4MATIC, BMW’s intelligent xDrive, and Subaru’s Symmetric All-wheel Drive are some of the most outstanding all-wheel-drive systems in the world today.
What are the differences between 4WD and AWD drivetrains?
Simply speaking, the four-wheel-drive unit is most commonly used in SUVs and larger trucks, that either usually, go off-roading or are used for towing heavy loads. The 4WD configuration can be activated by the use of a mechanical lever or even automatically by simply switching it on as when the situation demands. So in a way, the 4WD unit is switchable.
On the other hand, the AWD unit sends power to all wheels at all times. It is automatic and cannot be turned on or off. Yes, it can alter power sent to the wheels depending on which wheel needs it the most but the system is constantly working and is omnipresent. So either way, it is without a doubt that be it a 4-wheel drive type or an all-wheel one, your vehicle will have the most optimized output in terms of handling and control.
So, are there no disadvantages to these 4WD and AWD configurations?
The only underlying downside of these drive types is the additional cost they incur. On average, these units can raise the price of a car by about as much as $1500 to up to $4000. Then again, keeping in mind the diversity and versatility they bring in the overall driving experience is definitely a lot more than the price they ask.
Which drivetrain configuration then is the best?
If you own one car and one car only and want to get all your needs to be taken care of, the all-wheel or the 4-wheel drive types are definitely the most sensible way to go. They serve both form and functionality. However, if the cost of the investment is your prime concern, either the front-wheel or rear-wheel drivetrains will serve a greater purpose.