A car mostly has two axles. Even if it is a four-wheel drive car, it will have only two axles. There is the front axle and rear axle.
The front axle is often also called the steering axle as it is vital for turning the wheels. Depending on the driving wheels, you can also have the rear axle as the drive axle.
This is not to mean that you would not get a car with more axles, but over 99% of the cars made right now only have two axles.
You will get more axles on a vehicle when it is a semi-truck or bus. Considering the turning radius of a semi-truck or bus, they need more axles to support the weight and also help in turning.
We shall look more into what an axle is, its purpose, the types available, potential problems, and caring for it. You will have all the key information about axles by the time you get to the end of the guide.
What is an Axle? Why is it Important?
An axle is an important part of the car that sometimes we neglect to look at. Well, an axle is simply a rod that connects wheels and propels them in one direction.
The axle also retains the positions of the wheels ensuring there is proper drivability of the car.
When the engine applies a turning force to the axle, then it is the job of the axle to transfer the motion to the wheels as it moves.
In simple terms, the axle is responsible for delivering the driving power to the wheels from the engine.
Axle strength is quite important in ensuring that the axle can hold the car’s weight in addition to passengers or cargo that might be in the car. You can see it has more uses than transferring the engine power to the wheels.
The axle will also absorb any shock coming from driving over rough terrains. That is why an axle has to be made using robust materials that will resist fracturing, deformation, abrasion, and compression.
Other than the axle strength, you also have the axle stiffness. This is another factor that must be considered in axle design so that the car can achieve and maintain performance as it should.
Most cars would have sturdy front and rear axles. This means there will be a steady transfer of power from the engine to the wheels. You also experience better control when driving the car in different conditions.
Here is a video explaining how an axle works
A car will likely only have two main types of axles. You will mostly come across the front, rear, and stub axles. We look at them in detail below so that you can know which type of axle you have on your car.
Based on the name, you can know that this axle is located at the front of the car. Its work is mostly to help with the steering of the vehicle. It contains four main parts including the stub axle, ties rod, beam, and swivel pin.
Because of its location, it has to be robust. Keep in mind that the front of a car will have also many parts. So, it has to bear more weight too. That is why this type of axle is likely to be made of carbon steel or nickel steel.
You will come across various types of front axles. They include a dead front axle and a live front axle.
A dead front axle is designed to stay in place and does not rotate with the wheels. Such an axle and differential will have housing that keeps it from getting into contact with dirt and water.
The live front axle will deliver the driving power from the engine power from the gearbox to the front wheels. This is unlike the dead front axle which does not move.
A rear axle as the name suggests would be at the rear of the vehicle. It mostly comes in two halves. These halves are connected by using a differential. You will find that these axles are live most of the time. This is because they are responsible for driving the rear wheels of the car.
Just like the front axle, you can also get several types of the rear axle. They include;
- Semi-floating axle: This type of rear axle will connect the wheel to the flange and hold it securely on the outside of the axle shaft. There is a bearing that supports the axle shaft and another one is in the axle housing. You would find such type of axle in cars, medium-sized trucks, and SUVs.
- Full-floating axle: For this type, it also has two bearings and can effectively float in place and still maintain its position. Its work is to only transmit the drive torque. This makes them good for larger vehicles including heavy trucks. Also, some medium-sized trucks can have such an axle to improve the towing capacity.
- Three-quarter floating axis: It is a more complex design compared to the other two mentioned above. Well, the design is also what makes it more reliable. Its work is to help in maintaining the vehicle’s wheel alignment and also handle driving torque and side trust.
We had said that a car only has two axles, so what is a stub axle all about?
So, a stub axle would be found in rear-wheel-drive cars and will be attached to either end of a front axle by using kingpins. You can come across four types of stub axles depending on their arrangement and subcomponents.
- The Lamoine stub axle is an L-shaped spindle and has a kingpin instead of a yoke.
- Lamoine reverse has a reversed arrangement of the Lamoine stub axle.
- Elliot stub axle will be attached to the front axle using a kingpin, yoke, and cotter.
- Reverse Elliot will have a reversed arrangement of the Elliot stub axle.
Here is a video explaining more about axles
Can a Car Axle Break?
A car axle can break as much as it might be made using strong materials. Let us say the car shocks are worn or you keep hitting potholes in your area, you could then damage or even break the car’s axle,
The axle is also often flexed to accommodate the different road conditions. In time, it can also wear out and fail thus leading to a broken axle.
The axle is an essential part involved in the steering, braking, driving, and also transferring of the power of the engine to the wheels.
So, what happens when you have a bad axle? This means that there will be more wear and damage to these other parts mentioned.
For a bad axle, you can expect more pressure on the car shocks thus leading to premature wear. Of course, the result is having costly repair bills. Some also experience excessive wear of tires when the axle is bad.
It is important that you understand what could break an axle. Here are some scenarios where you can end up with a broken axle.
- Whenever there is too much load on the axle then it can potentially break. Yes, even if it is made of strong material, the material would of course have a breaking point too.
- Metal fatigue is also possible in an axle. This would be common in an older vehicle model or a car with high mileage. That is not all. Any car that is often overloaded will likely have this problem. The metal fatigue generally reduces the strength of the axle making it easily break after some time.
- Road conditions are also a key player in making the axle break or remain in good condition. That is why you have to watch out for potholes. Do not deliberately hit potholes or you might end up with a broken axle.
How Long Does an Axle Last?
How long an axle can last depends on a few things, but the average is around 10 years or over 90,000 miles.
How the axle was installed can be a big factor in determining if the axle can last long. If the axle is poorly installed, then it would not last long. If you need to change the axle, make sure it is done by a professional.
Of course, the quality of materials used to manufacture the axle also matters. The cheap axles are only cheap because of poor quality materials.
So, they might have a higher failure rate. That is why you should only get an axle from a reputable brand if you ever need to replace it.
You are advised to periodically check the axle for signs of wear. This helps you to catch a problem before it advances.
Listen for odd noises from the wheels and axles whenever you go over a bump or around a corner. This could mean there is a problem with the axle and it needs replacing.
You should always have the axle also maintained as part of maintaining the car. If you neglect it, then you might find some parts wearing out would also lead to the breaking of the axle.
So, the next time you are servicing the vehicle, make sure you also check the components attached to the axle.
Signs of a Broken Axle
So, how would you know that you have a broken axle? Below are the signs that help you know you have a broken axle.
- Vibrations: You may experience vehicle vibrations after hitting a big pothole, curb, or any other thing that might show you have hit an axle. Vibrations are often a sign that you have damaged the axle. Sometimes you can notice sluggish driving, steering, tire wobbling, and more. Just make sure you take a good look at the axle to see if it is in good condition or not.
- Loud clunking: Sometimes you may experience loud clunking whenever you put the vehicle into gear or the car seems to struggle to get the power to move. When the car is unable to transfer power, it could mean that there is slack in the axle.
- Leaking grease: When you notice there is grease leaking on the tire edge, it can mean that the axle boot is ripped. When the grease leaks out, you end up with a damaged axle that no longer works great. Make sure to ensure that the axle boot is replaced to keep the axle lubricated.
- Problem with increasing speed: If you notice that the car is running well, but the speed does not seem to increase, then there could be a problem with the axle. It needs to be checked because it is not transferring the power as it should.
Here is a video on how to tell if you have a bad axle
How much will it cost to replace an axle?
An axle price varies based on the make and model of the car. With an estimated budget of $500 to $1000 for the parts and labor, $100 should be enough.
What would happen if an axle breaks?
An axle breaking means that you lose power and control of the wheels. It does not always happen, but make sure the axle receives proper maintenance to avoid such scenarios.
Does a car have 4 or 2 axles?
Sometimes people count wheels and assume those are the axles. A car will mostly have 2 axles. Look from the side profiles and count. That is how you get the correct axle count.
One thing about axles is that they are built to last. Most people might never have to replace axles during the entire lifetime of the car. This does not mean that you should then abuse the car.
That is where the care for axles also comes in. Make sure you have the axle checked during routine maintenance and address any issues that might be cropping up.
Now that you know more about car axles, how well do you care for them? Talk to expert mechanics to know how best to maintain your car axles.