Reinventing Your Wheels: Why Your Choice of Drivetrain Matters
You’re chauffeuring your car junkie BFF, who’s admiring your new car and they ask, “is this front or rear wheel drive?” And there you are feeling stumped, as if trying to solve the daily double on Jeopardy. If it’s happened before, don’t worry – it will be the last time after you finish reading this article. Today, we’re going to discuss the various types of drivetrain systems out there, as well as their pros and cons.
Defining the Drivetrain
Before examining the various drivetrains out there, we need to understand what it is in the first place, and what it does. The drivetrain, which is not to be confused with the powertrain, is the system of parts that connects the transmission to a vehicle’s axles, making it possible for a car to move forward. The components that comprise the drivetrain include the following:
- Driveshaft – This lengthy tube of steel is connected to a car’s transmission at one end and the wheels at the other end. It transfers power from the transmission to other parts of the car.
- U-Joint – The U-Joint, which is short for universal joint, is the pivot point that transmits power to the driveshaft, allowing for it to change angles.
- CV Joints – CV joints, which is short for constant-velocity joints, have the ability to bend in any direction, so they can turn the drive wheels at a consistent speed.
- Differential – The differential is where the shifting of power ends before spinning the wheels.
- Axle shafts – These parts are single rotating tubes on either side of the differential, which transfer power from the final drive assembly to the drive wheels.
Now here’s the catch: the arrangement and function of these drivetrains varies from vehicle to vehicle. In other words, a front-wheel and rear-wheel drivetrain look and work a bit different.
Front Wheel Drive – FWD
Front-wheel drive is considered as one of the most practical choices for modern drivers. It’s name is self-evident since the motor provides power to your car’s front wheels to give you motion. In terms of arrangement, the motor is placed in what’s known as a transverse orientation, where the axes used to rotate the wheels sit parallel to the wheel itself (like this). With that said, there are advantages and disadvantages of driving a car with FWD.
Pros of FWD
- FWD is better suited to bad weather conditions such as ice and snow
- FWD weighs less than RWD transmissions, which increases fuel economy
- Driving a FWD vehicle is easier to master than RWD, making them better choices for new drivers
- Cars with FWD transmission are cheaper to buy since they’re cheaper to build
Cons of FWD
- Since the transmission is at the front, the car is heavy at the nose making it harder to handle
- Despite being cheaper to build/afford, these cars are more expensive to maintain due to the number of small parts they contain
- FWD transmission vehicles rely on front wheels for steering which further contributes to handling difficulties – that’s why it’s hard to find a sports car with this kind of transmission
- These transmissions are somewhat fragile and thus more susceptible to damage
Rear Wheel Drive – RWD
Due to advantages offered by FWD vehicles, fewer auto manufacturers are building cars with rear wheel drive. There are still many that do, however. Again, the name rear-wheel drive suggests the location of the axis of the motor’s rotation – the rear. Vehicles with this configuration are the opposite of front-wheel drive since they carry more weight at the back. This option, too carries it’s own set of pros and cons.
Pros of RWD
- Better balance, better torque, better handling making them perfect for sports cars
- Less susceptible to damage from road obstacles such as speed bumps and potholes
- Costs to maintain these transmissions are lower
- Ideal for towing due to more torque
Cons of RWD
- The handling, although smoother, is harder to control especially for new or less skilled drivers
- RWD vehicles are often pricier to purchase upfront (although they’re cheaper to maintain)
- Unsuitable for poor road and weather conditions (ie. ice, snow, wet surfaces)
- Reduced interior space due to arrangement of transmission and hardware
4-Wheel Drive – 4WD
While front and rear wheel drive are pretty straightforward, figuring out what four-wheel drive (4WD) might be a bit confusing. Cars with this kind of configuration give you the option of transferring power to all four wheels or just two. Many vehicles with four-wheel drive are available in two forms – part-time or full-time 4WD. A part-time system is designed for you to only drive in four-wheel mode when off pavement (driving on pavement in this mode causes extra wear on the vehicle). A full-time system, however, is intended for use whether you’re on or off paved surfaces.
Pros of 4WD
- Excellent traction in off-road conditions making them great for rural driving
- Can switch to two-wheel functionality to improve fuel economy
- 4WD cars have better acceleration than two wheel drive
- The resale value on four-wheel drive cars are higher than two-wheel drive
Cons of 4WD
- 4WD vehicles add a lot more weight than vehicles with two-wheel transmission
- The ride quality offered by 4WD vehicles are usually bumpy and rough
- More susceptible to tire and axle damage if used on dry pavement
- Vehicles with four wheel drive tend to have reduced fuel economy
Advance Wheel Drive – AWD
Finally, there’s advance wheel drive (AWD), which is also referred to as “all-wheel drive”. The name refers to drivetrains that transfer power to all four wheels. Most vehicles with this kind of drivetrain attempt to solve the problems found in FWD and RWD vehicles, so that you have the best of both worlds. Many AWD cars are adaptations of front wheel and rear wheel vehicles. Although the abilities of all-wheel drive vehicles vary considerably, cars with these drivetrains are usually built for on-road use.
Pros of AWD
- Cars with all-wheel drive tend to have better traction since all four wheels are spinning at the same time (ie. kicks in if one wheel gets stuck in snow)
- Better traction translates to better acceleration
- Great for poor weather such as thick snow and slush
- Although AWD costs more, the resale value is higher
Cons of AWD
- AWD use more power to keep all four wheels spinning, meaning reduced gas mileage
- AWD require more maintenance since their differentials need oil changes
- Although AWD improve acceleration and traction, but they don’t help with braking
- All-wheel drive vehicles are costlier than cars with other drivetrains
Putting the Right Spin on Things
So the question remains: Does it matter what drivetrain you have? The short answer is yes. It shouldn’t be the only factor you think about when deciding whether you should buy a particular car or not, but it is worth considering. You should think of costs and the amount of maintenance you’re willing to add on top of what’s already required of you. More importantly, however, you should think about where you live and the conditions you may have to encounter throughout the year. For instance:
- Front-wheel drive (FWD) – Ideal for those who live in a climate with a moderate amount of snow and rain, and for people who want a practical option.
- Rear-wheel drive (RWD) – The perfect option for those who want a sports car, and rarely encounter snow or rain.
- Four-wheel drive (4WD) – Vehicles with four-wheel drive are a great choice for those who plan on spending much of their road time…off road.
- All-wheel drive (AWD) – If you’re regularly commuting through snow, ice, rain and dirt roads, then all-wheel drive will work great for you.
By keeping your circumstances in mind (as well as your finances and style preferences), you’ll naturally narrow your options down. And to sum it all up, you’ll no longer be confused when someone asks you a question about drive-trains ever again.