Technical Car Info: AWD vs FWD vs RWD vs 4WD, A Look At Drivetrains!

Technical Car Info: AWD vs FWD vs RWD vs 4WD, A Look At Drivetrains!

two four-wheel-drive stuck in the mudOf all the decisions one must make when buying a new car, or buying a used car for that matter, choosing a drivetrain is probably the most complex. Almost every car manufacturer now offers either all-wheel-drive or four-wheel-drive models to go along with front-wheel-drive and rear-wheel-drive variants. Deciding which drivetrain is right for you is not easy with each variant having both great advantages and unfortunate disadvantages.

One thing is clear however. It will be impossible for you to make an informed decision without knowing the differences between each drive system as well as the advantages and disadvantages associated with them.

 
Let’s begin by explaining each technology!

Front-Wheel Drive or FWD

In a FWD car or truck, the engine’s power is relayed to the front wheels. Using the power received from the engine, the front-wheels are in essence “pulling” the car to create motion. The rear wheels do not receive power and are only “following” the front wheels.

Rear-Wheel Drive or RWD

In the case of a RWD car or truck, it is the rear wheels that receive power from the engine, and motion is created by the rear wheels “pushing the car”. Like a bicycle, the front wheels are not relayed to any power source and turn because of motion created from the rear wheels.

Four-Wheel Drive or 4WD

A part-time 4WD system allows the driver to manually select if the power from the engine is relayed to only two wheels or to all 4 wheels. The default setting on a 4WD car is usually rear-wheel-drive. Using a switch, the driver can select to have power transferred to all 4 wheels.

There are 3 settings a driver can choose from on a part-time 4WD vehicle: 2WD, 4Hi and 4Lo. By switching to either 4Hi or 4Lo, the driver engages all four wheels. The difference between Hi and Lo settings resides mostly in the torque provided to the wheels under each setting. Lo mode receives the most torque and the most power but also is restricted in speed and is most often used to get out of very difficult off-road conditions. Hi mode on the other hand would normally be engaged in snowy or slippery conditions.

Part-time 4WD vehicles can be damaged by driving in either 4Hi or 4Lo for extended periods of time, because under these conditions, the transfer case lacks a differential. This creates a situation where the wheels will not be turning at the same rate – for example when cornering – leading to transfer case damage.

A full time four-wheel-drive (4WD) system is, in reality, a part-time 4WD system to which has been added a differential, making it possible to engage all 4 wheels without damaging the transfer case. Unlike part-time 4WD, a full time all-wheel-drive system does not have a 2WD mode, and permanently engages all 4 wheels, usually sending 25% of the power to each wheel.  

A full-time four-wheel-drive system will normally have both a 4Hi and a 4Lo mode that provides the same characteristics as described above.

All-Wheel Drive or AWD

All-wheel-drive systems are identical to full-time 4WD system except they do not have a 4Lo mode. It is impossible to increase the low-speed torque to escape difficult situations, making AWD vehicles less capable in rugged terrain or harsh conditions. However, AWD vehicles are more popular than 4WD in today’s automotive market because all-wheel-drive is sufficient for most people’s driving habits.  

The popularity of all-wheel-drive has pushed many manufacturers to offer automatic AWD systems. These systems are, in reality, either front-wheel-drive or rear-wheel-drive vehicles that have the ability to transfer power to the rear or front wheels respectively in the event of traction loss.

Which drivetrain is right for me?

Now that you know how each system functions; you need to determine which one is right for you.  We have devised a small questionnaire designed to help you make that decision. So grab a piece a paper and a pen and write down your answers along with the number of points next to each response. Of course, if you are still unsure at the end or do not have the time to take the questionnaire, you can always ask us!

1)    When do you usually see the first snowfall in your region?

A)  September:  5 points

B)   October:  4 points   

C)   November:  3 points

D)  December: 2 points

E)   We rarely see snow: 1 point

F)    We never see snow: 0 point

 

2)    How many months is the grass in your area completely covered with snow?

 A)  4 Months: 5 points

B)   3 Months: 4 points

C)   2 Months: 3 points

D)  1 Month: 2 points

E)   We get 1-2 storms a year and the snow melts after a few weeks: 1 point

F)    It never snows: 0 point

 

3)    How long is your daily commute?

A)  More than 1 hour: 4 points

B)   30 minutes to an 1hour: 3 points

C)   15 minutes to 30 minutes: 2 points

D)  Less than 15 minutes: 1 point

E)   I walk or take public transportation, my car is only for family outings: 0 point

 

4)    Which vehicle category were you contemplating?

A)  Full-size  S.U.V. or pick-up truck: 4 point

B)   Small to midsize S.U.V.:2 point

C)   Large or small minivan: 1 point

D)  Full-size sedan: 1 point

E)   Sedan: 0 point

F)    Coupe/Hatchback: -1 point

G)  Convertible: -1 point

 

5)    Are you planning to pull anything with your vehicle?

A)  I will be hauling huge loads of over 10,000 pounds on a regular basis: 20 points

B)   Yes, we plan on pulling more than 3,000 pounds occasionally: 10 points

C)   Yes, we have small loads of less than 3,000 pounds: 5 points

D)  Yes, occasionally we will pull a light load (less than 1,500 pounds): 3 points

E)   No, we will not be pulling anything; we do not even have a trailer hitch: 0 points

 

6)    How many times will you be going off-road with your vehicle?

A)  We live off the beaten path and use rough roads every day: 10 points

B)   We have a cottage in the woods and go there every couple of weeks: 6 points

C)   We live outside of the city but most roads are paved: 3 points

D)  We live in the city or the suburbs and will never go off-road: 0 point

 

7)    What is an ideal vehicle for you?

A)    One that can go anywhere and pull anything and take me wherever I want to go: 10 points

B)    One that allows me to relax during my commute and be worry-free:  4 points

C)    One that offers a lot of cargo and passenger room for all the trips we take: 3 points

D)   I do not have an ideal vehicle. I just want to go from point A to point B when I need to: 1 point

E)     I want performance! (Skip to last section: What about rear-wheel-drive and part time all-wheel-drive.)

 

Here is the chart:

33 points or more: We recommend full-time Four-wheel-drive. If you have scored above 33 points, it means you need a vehicle that can survive brutal winters, or travel on broken roads on a daily basis, or have a long commute or that you will be towing large loads, or some combination of the above. Having the 4Hi and 4Lo modes will come in handy in rough road conditions and when you are pulling something with your vehicle. It will also help you easily cross any snow storm.

25 to 32 points: We recommend Full-time All-wheel-drive. With a score in between 25 and 33, you probably do not need a 4Lo mode to get out of really tough spots but  still need a good go-anywhere vehicle. This is exactly what you get with an AWD vehicle.

16 to 24 points: We recommend Automatic All-wheel-drive. As mentioned in the definitions, automatic all-wheel-drive systems transfer power to wheels that are losing traction if need be. They combine the safety of an all-wheel-drive system with the fuel economy of a front or rear-wheel-drive vehicle. If you scored between 16 and 24, you do not need full-time systems.

0 to 15 points: We recommend Front wheel drive. Your lifestyle probably does not warrant sending power to all four wheels. Go with front-wheel-drive to get better fuel economy, lower repair costs and less maintenance.

 What about Rear-wheel-drive and Part time all-wheel-drive?

You probably have noticed that we do not recommend either rear-wheel-drive cars or part-time four-wheel-drive vehicles in our chart. How come?

Let’s begin with Part-time four-wheel-drive. We do not recommend it because put simply, you do not need it. Many full time four-wheel-drive systems will provide you with great off-road performance while still allowing you to drive on-road, something that cannot be done in a Part-time 4WD vehicle.

Rear-wheel-drive systems are a little different. We would recommend them for one specific reason: fun! A RWD vehicle is much more fun to drive. It offers better handling than a front-wheel-drive vehicle and better driving dynamics than an AWD car. Most performance vehicles come in rear-wheel-drive configuration because of these advantages.

So, our recommendation goes as follows: if your main priority is fun behind the wheel, we strongly suggest going for a RWD vehicle. Just remember that having a rear-wheel-drive vehicle is not ideal in winter. Sure, most current new vehicles have stability and traction control systems, but rear-wheel-drive vehicles can still be tricky in slippery conditions and you risk spinning out of control if you are not careful.

Regards,

The Auto Consultants

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