Tag Archives: main reducing gear
Why An FR Is More Expensive Than An FF
Why is an FR (rear-driven) always more costly than an FF (front-driven)? This is truly an interesting topic. There is quite a possibility that the manufacturers deliberately adopt FR to the high-end cars to make it sporty and high-class. But today let’s reveal the technical reasons.
1. Material costs
To begin with, we should understand the machinery difference between FR and FF. In an FF, the entire transmission system is located in the front, the power generated by the horizontally held engine goes through a compact gearbox and is transmitted to the main reducing gear for deceleration and torsional increase, then directly drive the front wheels.
On the contrary, the longitudinal engine generates power to a big gearbox, then uses a long transmission shaft to transfer the power to the main reducing gear at the rear wheels, then output the power and drive the rear wheels. So, because the gearbox and main reducing gear are both small, it does not require high cost, thus decreasing the total cost. But this is not the real factor, and the key is as follows.
2. Chassis design
As described above, all the heavy components of an FF are in the front, so we just need to solder a sub-frame to the front for the entire load-bearing to enhance the mechanical hardness, no need to care about the rear. This really means a lot to the price, because the material for reinforcing the frame is usually steel of ultra-high strength and it’s really expensive. In addition, the FF car has cost advantages in the manufacturing. Without the transmission shaft and main reducing gear, the chassis can be made flat, which saves lots of processing costs.
Things go differently when it comes to an FR. First, its chassis has to hold the entire power transmission system, not only the front, but the middle and the rear need to be strengthened, so the strength of the chassis is greater than that of an FF. Second, the workpiece processing is more difficult. In addition to accommodating the engine, FR’s chassis should also have protuberances for the gearbox, not to mention the intermediate transmission shaft that goes through the car body, as well as the main reducing gear at the rear. All of these components require appropriate channels in the chassis. What’s more, the chassis has a higher intensity. As a result, the manufacturing cost is higher than an FF.