RWD vs FWD vs AWD vs 4WD!
Hi everyone! Your favourite pretend engineer is back for another post! Today we are talking about which of the four(usually!) wheels are spun by the engine.
Any of the four wheels can be spun by the engine of a car, so there are mainly 4 different types of power disctribution to the wheels. These are:
Front wheel drive: the engine spins the front wheels only. Due to this cofiguration, the engine, transmission and differentials are all in the front of the car.
Advantages: cheap to design and build, easy to drive.
Disadvantages: when pushed to the limit of grip, the car tends to understeer(front tires lose grip), limited in the amount of power you can have while conserving favourable handling characteristics.
Rear wheel drive: the engine spins the rear wheels. The engine can be in the front, middle or rear of the car(in respect to the axles).
Advantages: more fun to drive, you can drift and do burnouts, reliable and stable handling characteristics up to the limit of grip, good car weight balance.
Disadvantages: once at or past the limit of grip, controlability of the car is hard to manage for an average person. It´s also expensive and more complex to design and build.
All wheel drive: the power of the engine is sent to all four wheels. In these systems, there are usually three differentials. One is inbetween the axles, which spits the power for the axles. The two remaining differentials are on each axle, which will spit the power according to how much each wheel needs. This system is used for very low grip conditions like extreme rain and snow, or for good lap times and 0 to100kph accelerations(in certain cases). This system usually has a preference for an axle, but when the oposite axle loses traction, it sends the required amount of power to regain stability.
Advantages: higher levels of grip, still gets good fuel economy, can be used in a wide range of cars.
Disadvantages: expensive, complicated and heavy.
4 wheel drive: the power is also sent to all 4 wheels, but not in the same way. In 4WD cars, a transfer case is used to split the power between the axles, so all wheels have power. The problem is that if the transfer case is working properly, all wheels will have the same power and torque to ensure that they are spinning at the same speed to ensure maximum grip in off roading conditions. But on the road, the car won´t turn properly if the wheels are all spinning at the same speed. This is because, in a corner, the inner wheels have less distance to cover in comparison to the outer wheels. This discrepancy will mess with the handling characteristics of a 4WD car. That´s why most 4WD cars can choose wether to have all 4 wheels powered or not.
Advantages: best at off roading, proven technology.
Disadvantages: worse fuel economy, heavy.
Any of the four wheels can be spun by the engine of a car, so there are mainly 4 different types of power disctribution to the wheels. These are:
Front wheel drive: the engine spins the front wheels only. Due to this cofiguration, the engine, transmission and differentials are all in the front of the car.
Advantages: cheap to design and build, easy to drive.
Disadvantages: when pushed to the limit of grip, the car tends to understeer(front tires lose grip), limited in the amount of power you can have while conserving favourable handling characteristics.
Rear wheel drive: the engine spins the rear wheels. The engine can be in the front, middle or rear of the car(in respect to the axles).
Advantages: more fun to drive, you can drift and do burnouts, reliable and stable handling characteristics up to the limit of grip, good car weight balance.
Disadvantages: once at or past the limit of grip, controlability of the car is hard to manage for an average person. It´s also expensive and more complex to design and build.
All wheel drive: the power of the engine is sent to all four wheels. In these systems, there are usually three differentials. One is inbetween the axles, which spits the power for the axles. The two remaining differentials are on each axle, which will spit the power according to how much each wheel needs. This system is used for very low grip conditions like extreme rain and snow, or for good lap times and 0 to100kph accelerations(in certain cases). This system usually has a preference for an axle, but when the oposite axle loses traction, it sends the required amount of power to regain stability.
Advantages: higher levels of grip, still gets good fuel economy, can be used in a wide range of cars.
Disadvantages: expensive, complicated and heavy.
AWD layout
4 wheel drive: the power is also sent to all 4 wheels, but not in the same way. In 4WD cars, a transfer case is used to split the power between the axles, so all wheels have power. The problem is that if the transfer case is working properly, all wheels will have the same power and torque to ensure that they are spinning at the same speed to ensure maximum grip in off roading conditions. But on the road, the car won´t turn properly if the wheels are all spinning at the same speed. This is because, in a corner, the inner wheels have less distance to cover in comparison to the outer wheels. This discrepancy will mess with the handling characteristics of a 4WD car. That´s why most 4WD cars can choose wether to have all 4 wheels powered or not.
Advantages: best at off roading, proven technology.
Disadvantages: worse fuel economy, heavy.
4WD layout
I hope you enjoyed reading this post! It is possible that I´ve made a mistake somewhere, so if you spot something, please let me know.
Bye!
PS: rear wheel drive is best!
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