Car wheel parts Basic parts of a car wheel

Car Wheel Parts, Diagrams and Functions

Wheels are the oldest rounded construction elements that accelerate an automobile. They are set up beneath the truck vertically, allowing for movement while also supporting both heavy cargo and the vehicle. Every type of vehicle, from little cars to large trucks, depends on its wheel as its fundamental working component. In recent years, cars have been modified to have a range of bodies, designs, and sizes. Some auto parts have been replaced with newer variants or are no longer in production.

Furthermore, every automobile, from a Ferrari to a Ford Pinto, depends on the wheel, the most basic of machines. The wheel might be the greatest invention that man has ever invented; there is no avoiding it right next to the fire (no pun intended). Cars and trucks would only be pricey yard ornaments without wheels and tires. Well, in this article, I will be discussing the basic parts of a car wheel and their functions.

Let’s dive in!


Car wheel parts Basic parts of a car wheel


Car wheel Parts and their functions

The hub, spokes, and rim make up the wheel. the region where the lateral surface of the rotor, the lug bolts, and the axle seat all come into touch. The following are the various parts of a car wheel:

  • Barrel
  • Bolt circle
  • Beads
  • Centre bore
  • Center cap
  • Flanges
  • Lug hole
  • Outer lip
  • Spoke
  • Tire
  • Valve system
  • Wheel bearing
  • Wheel rims
  • Wheel hub
  • Wheel fasteners


Wheel Bearings


Wheel bearings are frequently made using antifriction bearings. They form a low-friction link between the still vehicle and its rotating wheels. The inner race, rolling element, and outer race are the three fundamental components of this type of bearing.
Wheel bearings are primarily used so that the wheels may rotate smoothly and with the least amount of resistance. In order to help reduce friction when the wheels spin, car wheels feature hubs in the center, where the wheel bearings fit snugly within the hub and travel on a metal axle shaft.
The seal or shield, which keeps lubrication inside and debris and water out, and the bearing cages, which divide the different rolling elements as they bend, are other components of antifriction bearings. The type of load, the maximum bearing speed, the location of the bearing on the vehicle, and the intended use of the vehicle must all be taken into consideration when choosing a wheel bearing.
When selecting a wheel bearing, care must be taken to take into account the kind of load, the maximum bearing speed, and the location of the bearing on the vehicle.

Wheel rims

Typically, confusion develops between the rim and the wheel. Sometimes the wheel is referred to as a rim and vice versa. Let’s make a distinction between the two: the rim is only a portion of the wheel, but the wheel is composed of the tire and other parts, in addition to the rim. In addition, the tire is secured in place by the skeleton’s outside edge, which is known as the rim. Its cylindrical shape enables the annular housing to be secured to the wheel and sealed. To seal the air inside tubeless tires, the tire and rim must be properly assembled. Between the rim and the tire on older models of cars were tubes.

To endure the weight and force of the car, the rims are made of sturdy metal, such as steel. The size of the car tire is determined by the rim’s width and diameter. Custom rims are available as aftermarket car parts. These custom rims cost extra and can be colored and decorated in whatever you choose.

The barrel of the rim provides a platform for mounting the tire. The type of wheel mounted is determined by the center of fall, which is the inside diameter of the cylinder. The drop center for front-mounted wheels is close to the front of the wheel. Rear-mounted wheels, on the other hand, have fall centers close to the back of the wheel. The barrel edges are formed into flanges to prevent tires from slipping when driving. They have flat pieces called beads. The tire’s edge rests on this surface created by these flat areas.

Wheel hub

The hub, which is the most important component, is where the wheel is attached. It has a hole in the middle that is used to mount the wheel to the axle. When the driver presses the brake pedal, the brake discs rest against the wheel hub to ensure that the vehicle brakes. The center hole is covered by a detachable center cap on the outside of the wheel. Typically, a wheel disc that is either removable from or permanently attached to the rim serves as the link between the hub and the rim. Spokes are used on some automotive wheels to join the rim and hub. The structural integrity of the wheel is also provided by the spokes. Modern wheels typically have styled spokes for aesthetic appeal.

Make sure the central hole on an aftermarket car wheel is the same size as the OEM or OE wheel before you buy it. It will cost more to use wheels with a larger central bore since hub-centered rings are required to close the gap. The center disk is situated just outside the center cap on spoked vehicle wheels. The wheel offset is determined by the depth of this disc about the centerline. On the middle disc, lug holes are commonly drilled to produce bolt circles. The holes are known as “lugs” where the wheel nuts are fastened. The bolt circle diameter is the size of the bolt circles made by the lug holes (BCD). The bolt pattern is determined by this dimension and the number of holes.

Wheel fasteners

The method by which the rim is fastened to the hub or axle flange is a critical aspect of the design of the wheel and tire. On every kind of vehicle, the wheel studs are employed as wheel fasteners in the hub or axle flange. These are probably pressed into a hub or flange for a tighter union and are threaded bolts or studs. To prevent the stud from fully piercing the hole in the hub or flange, the head of the stud is typically wider than the hole. The center of the hub or flange is elevated slightly and placed in the center of the rim to properly center the wheel.


The barrel refers to the area of the car wheel that lies between the outboard face and the inboard rim edge. The barrel’s function is to provide a surface on which the tire can be mounted. The drop center, which influences the type of mount wheel, is the barrel’s inner diameter. The drop center is close to the front of the wheel in front-wheel drive cars. On the other hand, a vehicle with rear-wheel drive has drop centers close to the back of the wheel. Flanges formed by the barrel’s sidewalls prevent the tires from slipping as the car is in motion.


Bolt circle

The bolt pattern of a wheel is often known as the bolt circle or pitch circle diameter. This is the space that the lug bolt generated. The bolt circle is calculated by multiplying the number of lugs by the diameter of the fictitious circle the lugs’ centers form. For instance, a 54′′ bolt pattern would have 5 lug bolt holes and a 4-inch BCD. Cross-fitting wheels made for multiple automobile manufacturers is challenging since bolt circles typically vary between the wheel and car manufacturers.



Tire beads provide the primary function of securely fastening the tire to the outside of the wheel. To do this, the wires’ pressure is used to force the rubber firmly into the wheel’s frame. The wheel that will transport energy also includes beads. If the beads are broken, the energy may transfer improperly and shake the whole car, especially when it is moving quickly. Because they provide an airtight seal against the wheel and enable a more effective transfer of forces while the automobile is moving, beads are crucial.


Centre bore

The wheel is correctly centered on a vehicle by the machined aperture in the center of the wheel. A wheel must be hub-centric to lessen the likelihood of vibration. The functional space that extends above the axle and bears the weight of the car is often contained in this void. The replacement wheels cannot be installed if the hub collar’s diameter is greater than the central bore. The wheel can be fitted similarly if the center bore is greater than the hub’s diameter, but an unintended diameter difference would be challenging.

Center cap

The rims and tires of the car are shielded from dirt and sunlight by high-quality car wheel center caps. These automobile wheel covers are an excellent purchase, especially for drivers who leave their cars parked in public areas. The spoke-filled middle of the wheel is where the center cap is located. The center cap on some models can be taken off. But the majority of rims don’t have detachable center caps. While a wheel can be used without a center cap and still operate properly, the center cap gives the wheel a more finished and uniform appearance.


A wheel flange often acts as a connection to connect the wheels of the vehicle to the axle. These are mechanically locked to the spindle’s end or the drive axle. Additionally, they are on the sides of the wheel to stop the tire from unduly slipping. Car wheels have traditionally been mounted using wheel flanges and lug nuts. The tire will remain attached to the wheel even in adverse weather or on uneven surfaces thanks to the flanges that are found on both ends of the wheel.


Lug hole

On the center disc, the lug hole is typically machined to resemble a bolt circle. It is through these holes that the lug nut is fastened. The voids that the center cap typically covers are known as lug holes. The bolt circle diameter is the size of the circle made by the lug holes. The threaded wheel stud on the vehicle’s axle is connected to the wheel hub by the lug nut, which secures the wheel in place and centers it correctly. It is a kind of nut fastener with a conical (tapered) end or a round end.


Outer lip

The most repairable section is the outer lip, which is the portion that will most likely collapse when a wheel strikes a pothole. Up until the tip touches the face of the wheel, the lip technically can be deeper or larger. A deeper outer lip is more vulnerable to damage from impacts since the spokes cannot support it as well. The distance from the wheel face to the edge of the outer lip, which is on the outside, is specified.



The spokes are crucial in securing the plate in the wheel’s center to the rim of the wheel. The lugs and bolt holes used to attach the wheel to the car are kept here. Additionally, the spokes protect the outer edge and shelter it from slight blows. There are countless variations of these spokes. The traditional type has five spokes, however, some also have elaborate decorations or only have three. The material and design have an impact on the stability and strength of the spokes.



Everyone is aware that tires are designed to transmit traction, torque, and braking forces to the road surface as well as carry the weight of the vehicle and maintain the direction of travel. To carry out these tasks, tires are filled with compressed air and built of flexible rubber.

They are regarded as a component of the suspension system. In essence, tires are covers that keep wheel rims from rubbing or making contact with the ground. The threads that directly touch the ground and degrade with time are the fundamental components of a tire. Typical threads feature patterns, which are grooves and notches. This design is intended to maximize tire-ground contact friction and steer water and other debris away from the wheel.


Valve system

Car tires’ valve systems allow for inflation and deflation. The tire pressure monitoring system is built into the valve mechanism on car wheels, allowing the driver to always be aware of the tire pressure level. The valve’s purpose is to keep air or nitrogen inside and keep it from escaping. As a result, it is crucial for maintaining tire pressure and safe driving.

Wheels often have two valve stems for a pair of purposes. The first involves using a valve stem to pump air in, and the second involves refilling nitrogen air. Simply put, one valve stem is used to cleanse ordinary air, and the other stem is utilized to pump nitrogen.




Watch the video below to understand the various parts of a car wheel:



What are the parts of a car wheel?

The Basic Parts of a Car Wheel and Tire
  • Tire – This is pretty simple and obvious. We all know where the tire is and what it looks like. …
  • Rim – If the tire is the skin, then the rim is the skeleton of the wheel assembly. …
  • Hub – The hub is the center part of the wheel that the rim attaches to.

What are the 4 components of a wheel?

Both driving and non-driving axles have these parts, which comprise the wheel hubs, bearings, rims, tires, and fasteners.

What are the types of rims?

The 4 Different Types Of Rims You’ll See On Cars

  • Steel Rims: This is the most common of all the rims.
  • Alloy Rims: Alloy rims are next in line.
  • Chrome Rims: Chrome rims are not as common as alloy and steel rims.
  • Spinners: This was very prominent in the 90s.


What are the components of wheel assembly?

The hub, knuckle, bearing, brake caliper, brake disc, and ball joints typically make up the wheel assembly. The knuckle is the stationary component in a wheel assembly, whereas the hub rotates.

What part of a car wheel is the rim?

The “outside edge of a wheel, retaining the tire” is known as the rim. On wheels placed on autos and other vehicles, it makes up the outside circular pattern of the wheel.

What is the hub of a wheel?

One essential part of the rotating system is the wheel hub assembly. It keeps your wheel fastened to the vehicle and permits free rotation of the wheel. The wheel hub assembly is located in the middle of each wheel and serves as a location for the wheel bearings.

What is a wheel bearing?

The component that joins the wheel to the axle, known as the wheel assembly, is the wheel bearing. A metal ring holds a group of steel balls (ball bearings) or taper (tapered bearings) together. It makes it possible for the wheel to spin easily and with little resistance.

What happens when wheel bearings fail?

If your wheel bearing breaks, the wheel may stop while you are driving or perhaps come off entirely. It’s very important to keep an eye on these and keep them maintained because, at the least, a failing wheel bearing can/will cause severe damage to your car before a wheel falls off.

How do I know my wheel bearing is bad?

  1. Bad Wheel Bearing Symptoms
    Humming Noise
    Squealing, Growling
    Clicking Sound
    Wheel Wobble
    ABS Failure
    Uneven Tire Wear
    Vehicle Pulls to One Side
    Steering Wheel Vibration

How much is a wheel bearing cost?

A replacement wheel hub often costs between $200 and $500, whereas a wheel bearing typically costs between $50 and $120. Be cautious when purchasing new bearings and wheel hubs because many inexpensive parts are sad of poor quality. Well, the price can vary depending on your location. However, it is cheaper here in Australia.

How long will noisy wheel bearing last?

Wheel bearing durability is difficult to predict because, as we’ve already discussed, a variety of other elements can have a significant impact. However, a wheel bearing can typically endure between 136,000 and 160,000 kilometers, or 85,000 and 100,000 miles.

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In conclusion, a car wheel is a wonder of engineering precision, made up of a number of vital parts that function in unison to ensure safe and efficient transportation. Each component is essential, from the strong steel or aluminum rim providing structural support to the rubber tire securing the road. The sidewalls absorb shock and keep the tire’s shape, while the tread pattern affects traction. The lug nuts fasten the wheel to the vehicle’s hub, while the valve stem permits inflation and pressure monitoring.

Together, these components make up a sturdy and dependable wheel assembly that enables cars to travel over a variety of terrains, withstand great forces, and offer a comfortable and regulated ride. Road safety and extending the lifespan of this crucial vehicle system depend on regular maintenance and an awareness of the significance of each component. Let’s keep in mind the significance of appropriate maintenance and attention to detail as we draw to a close our investigation of automobile wheels. This will ultimately result in safer and more pleasurable road trips.

That is all for this article, where the parts of a car wheel are discussed along with their functions and diagrams. I hope you learn a lot from the reading, if so, kindly share with others. Thanks for reading, see you around!