Visually distinguish front-wheel drive car from rear-wheel drive or all-wheel drive under the power of not every motorist, especially if the hood is closed, and the bottom is hidden by protection. However, front-wheel drive It has a number of characteristic design features that give its device even when cursory inspection. Unlike the classic scheme with a driveshaft going back, here the entire power plant is arranged in the front of the body, and the torque is transmitted directly to the front wheels.
Understanding that, What the front-wheel drive looks likeIt is necessary not only for general development, but also for competent diagnosis of malfunctions of the chassis. When inspecting the bottom of the car, the absence of a massive tunnel for the driveshaft is striking, which makes the floor in the cabin more even. Instead, attention is drawn to short but powerful shafts that go to the hubs of the front wheels through joints of equal angular speeds, known as the βSpace of the Frontβ shafts. SRUSS.
In this article, we will examine in detail the anatomy of the transmission so that you can accurately determine the type of drive and understand the principles of its operation. Knowing these nuances will help you when buying spare parts or communicating with masters at the service station, as the design of the car is not a problem. front-wheel drive The car has its own unique service.
Design features of the layout under the hood
If you look under the hood of a modern front-wheel drive car, you can see that the engine is located transversely relative to the movement of the car. This arrangement allows you to use the space of the engine compartment as efficiently as possible, freeing up space for passengers in the cabin. The main visual sign is that gearbox It is adjacent directly to the engine block from the side, rather than being moved back, as in classic rear-wheel drive models.
From the gearbox depart two drive shafts of different lengths, which are connected to the hubs of the wheels. These shafts pass through the subframe and suspension elements, making their location quite difficult for visual analysis without a lift. Presence is the presence srussians at the ends of the shafts is a key marker indicating the transfer of rotation to the front axle.
β οΈ Attention: When inspecting the engine compartment, do not try to move the drive shafts or engine mounting elements by force - this can lead to damage to the anthers or violation of suspension adjustments.
The layout of units in front-wheel drive cars is often very dense. Access to certain sites, such as grip or flywheelIt can be difficult and require partial disassembly of adjacent systems. This is a fee for the compactness and efficiency of using the internal volume of the body.
Visual signs from the bottom of the car
The most complete picture of this, What the front-wheel drive looks likeIt gives an inspection of the car from below on the lift or observation pit. The first thing that catches the eye is the absence of a driveshaft stretching along the entire bottom to the rear bridge. The space under the cabin floor is free, which often allows you to make the exhaust system more direct and simple.
The main attention should be paid to the front suspension. You will see two shafts coming out of the gearbox differential. One of them is usually shorter than the other due to the displacement of the power unit to one side of the engine compartment. At the ends of these shafts are located internal and external SRUSSClosed with corrugated anthers that protect the lubricant from dirt and moisture.
- π The absence of a driveshaft and a rear gearbox (stocking) on the rear axle.
- βοΈ The presence of two drive shafts running from the gearbox to the front wheels.
- π‘οΈ The presence of corrugated anthers of SRUS in the area of the front hubs.
- π A flat floor in the cabin without a high central tunnel (in most cases).
The rear of the car looks much simpler: there can be either a simple beam or a multi-link suspension, but without heavy mechanical components of the transmission. Brake mechanisms at the rear also do not have torque supply, which confirms the absence of drive on the rear axle.
Pay attention to the interior of the front wheel: if you turn the steering wheel you see a thick shaft going deep into the body to the box, and a corrugated case (dust) - you are clearly front-wheel drive.
Scheme of transmission and SRUS operation
The central element transmitting the force is the differential built into the gearbox body. It is he who distributes the torque between the two. drive-shaftallowing the wheels to rotate at different speeds when cornering. Without this mechanism, the car would constantly be carried, and the tires were washed unevenly.
The most vulnerable and noticeable elements are joints of equal angular velocities. They are divided into internal (tripoid or ball) that are attached to the box, and external, connecting to the hub of the wheel. Outside Ε RUS It is experiencing enormous loads, as it must transmit rotation even at large angles of rotation of the wheels.
| Element | Location. | Function | Visual sign |
|---|---|---|---|
| Inner SRUS | At the checkpoint hull. | Suspension travel compensation | Pear-shaped anther, walks less |
| The Outer SRUSS | At the hub of the wheel | Turning gear | Spherical anther, often crunchy |
| Drive shaft | Between the SRUS. | Connection of elements | Smooth metal bar |
| Dust. | On the hinges. | Mud protection | Corrugated rubber/plastic |
Damage to the anther leads to a rapid failure of the node, as the abrasive dust mixes with the lubricant. Therefore, when regularly inspecting the bottom, the condition of these protective elements should be checked first. The resource of modern SRUS with whole anthers can exceed 300,000 kilometers of run.
βοΈ Diagnostics of actuator status
Differences from rear and all-wheel drive
To make it clear, What the front-wheel drive looks likeIt is useful to compare it with other schemes. In rear-wheel drive cars (RWD), the engine is often located longitudinally, and a massive driveshaft goes to the rear wheels. In all-wheel drive versions (4WD/AWD), the driveshaft is also present, but it transfers the moment to both axles, which makes the design of the bottom more complex and heavy.
Front-wheel drive wins in compactness and weight, but loses in mass distribution. When accelerating, the weight of the car is redistributed to the rear axle, unloading the front drive wheels, which can cause slippage. The rear-wheel drive lacks this drawback, but requires a more complex and expensive transmission maintenance.
β οΈ Attention: Do not attempt to tow a front-wheel drive car with the front wheels raised without turning off the drive or removing the shafts - this can lead to the transmission being destroyed due to the lack of lubrication of the rotating gears.
Visually, all-wheel drive car can be distinguished by the presence of a gearbox behind and a driveshaft, even if the front design looks like a conventional front-wheel drive. Many modern crossovers are based on front-wheel drive platforms, getting a plug-in rear axle, which creates a hybrid visual picture.
Why is front-wheel drive safer for beginners?
The front-wheel drive car during skidding tends to demolish the front axle (sluggishness), which instinctively causes the driver to drop gas and level the trajectory. The rear-wheel drive, when skidding, goes into uncontrolled rotation, requiring counter-rule and experience to stabilize.
Diagnostics of drive failures
Understanding the device helps to identify problems faster. The most common fault is the wear of external srussiansThis is a characteristic crunch when turning the wheels and moving. If the rudder is turned and the beginning of movement is heard rhythmic cracking, then the hinge requires replacement.
Another sign of problems may be vibration of the body during acceleration. It often indicates an imbalance of drive shafts or wear of internal hinges. Visual inspection can reveal torn anthers through which the lubricant has flowed - in this case, the knot is already contaminated and must be replaced or severe bulkhead.
- π Crunch when cornering is a sign of wear of the external SRUS.
- π Vibration during acceleration is a problem with balancing the shafts or the internal hinge.
- π§ The traces of lubrication on the inside of the wheels are a torn anther.
- π Beating the steering wheel is a possible backlash in the drive connections.
Timely diagnosis avoids more serious breakdowns, such as jamming of the shaft or damage to the glands of the transmission. Regular inspection of the bottom of the car after off-road trips is a good habit for the owner of a front-wheel drive car.
The main enemy of front-wheel drive is dirt and water, falling through torn anthers. Timely replacement of anther is several times cheaper than replacing the entire ShRUS collection.
Advantages and disadvantages of the scheme
The popularity of front-wheel drive is due to a number of economic and operational factors. The absence of a driveshaft and rear gear reduces the total weight of the car, which has a positive effect on fuel consumption and acceleration dynamics. In addition, this arrangement allows you to increase the space of the cabin.
But the scheme has its drawbacks. The design of the front suspension is more loaded, since it has to combine the functions of control, damping and torque transmission. This results in more complex and expensive chassis repairs compared to simple rear-wheel drive beams.
It is also worth noting the effect of "tork styre" (torque on the steering wheel), when with a sharp acceleration on a slippery road, the steering wheel can escape from the hands. This requires the driver to be more focused and hold tight, especially on powerful cross-engine modifications.
β οΈ Attention: When installing non-standard wide wheels or large-drive wheels on a front-wheel drive car, the load on the bearings of hubs and SRUS increases, which can reduce their resource.
Despite some nuances, for most urban conditions, front-wheel drive remains the optimal choice. It provides good exchange rate stability, predictable behavior and economy, which makes it the standard for the modern automotive industry.
The Myth of Front-Wheel Drive
It is believed that the front-wheel drive is always worse than corners. This is not quite so: modern stabilization systems (ESP) and competent suspension setting allow front-wheel drive hot hatch to show on the track results comparable to the rear-wheel drive classics.
Frequently Asked Questions (FAQ)
How do I know exactly what type of drive I canβt see the bottom of the car?
Look in the technical passport (TCS) of the car: there is a number of driving wheels (4x2 - two leading). You can also find a VIN code and break the complete set online. Visually: if under the hood the engine is cross and a box is screwed to it from the side - this is almost certainly front-wheel drive.
Can you make a full front-wheel drive?
Theoretically possible, but in practice this requires a complete replacement of the platform, the installation of a driveshaft, a rear gearbox, a different gearbox and rear suspension. The cost of such a conversion will exceed the price of a new all-wheel drive car.
Why does the right anther rupture more often than the left one on front wheel drive?
This is due to design: the right drive shaft is usually longer and consists of two parts with an intermediate support, which creates more points of potential wear. It is also more likely to be exposed to dirt from the wheel.
Is it dangerous to drive with a crispy SRUS?
Yes, dangerous. The joint can break down at any time, leading to a jamming of the wheel or a breakaway of the shaft. This can lead to loss of control and an emergency situation on the road.
Is there a driveshaft at the front wheel drive?
No, the term "drivershaft" refers to a long shaft that transmits moment to the rear axle. In front-wheel drive, short "drive shafts" or "half-axles" with SRUS are used.