AE Unit 4 Wheels and Tyres Notes
AE Unit 4 Wheels and Tyres Notes
AE Unit 4 Wheels and Tyres Notes
The wheels and tyres have to take the cushioning effect and the vehicle load so that they can cope up
with the steering control. In today's article, I will discuss in detail about wheels and tyres along with its
advantages, disadvantages and applications.
What is a Wheel?
A wheel is a circular object having a rim and a hub as the major parts revolve around an axle to
enable it to move easily over the ground.
Types of Wheels:
There are 3 types of wheels, those are as follows:
This type of disc wheel will be used by Majority of manufacturers all over the world.
This type of wheel consists of two parts. One is the steel Rim and the other is the Pressed steel
disc.
It is possible to mount or remove the tyre from the wheel with the help of well only, else it is not
possible.
It is possible to pass the tyre over the opposite edges of the rim, when the bead of the tyre is
resting in the well.
The steel disc is used for the functioning of spokes. The wheel is fitted along with the tyre onto
the axle by tightening nuts onto the mounting studs which are fixed on the flange.
Some holes or slots are generally provided in the wheel disc in order to allow the air to the inner
side of the disc for better cooling of the brake drum.
Especially for heavier vehicles like trucks, buses etc.which are bulkier and doesn't fit in the well region.
Therefore,the well rims are not used for them.
In these type of wheels, the loose flange and the lock ring has to be removed first to remove the
tyre and these rims will be used only by tubed wheels.
Robust construction
Simplicity
Ease of cleaning
Lower cost of manufacturing
Less maintenance
High production
These wheels are used in heavy motors like buses and trucks.
2. Wire Wheel:
Steel Rim
Spokes
Hub
Steel Rim:
Hub:
The wire wheel has a separate hub which is attached to the rim and a number of wire spokes are
attached to it within the disc.
Spokes:
Each spoke is fitted at one end of the hub while the other end is pushed through a hole in the
wheel rim.
A tapered nut called nipple, is screwed down pulling the spoke tightly.
Make sure that spoke should not be too loose or too tight, else the rim would distort.
The spokes carry the weight of the vehicle and can transmit the driving torque and the breaking
torque and also withstand the side forces while moving on corners under tension.
The spokes are mounted in a Criss-cross fashion which are long and thin wires doesn't carry any
compressive or bending stress but they are always sustained under tension.
This type of wheel was used in earlier days but it's use is limited for racing cars and
vintage cars.
Before 5 yrs from today, the wire wheel will be used in bikes also.
Traditionally, it is much used in bicycles also.
The latest trend in the case of automobile wheels, was the usage of wheels made by aluminium
alloys or magnesium alloys.
The strength of the forged wheel is very high compared to the cast wheel.
Therefore, light alloy cast wheels will be used in cars whereas forged wheels will be used in
heavy vehicles.
Light alloy wheels are better conductors of heat which helps the wheels to dissipate the heat
which is generated by the tyres or brakes.
The forged wheels and the cast wheels have to be machined to produce better appearance.
The main advantage of light alloy wheels is, it weighs about 50% of Steel wheel and 70%
of Aluminium alloy wheel for similar strength.
Wider rims are possible in this case of light alloy wheels in order to improve the stability
on cornering.
Magnesium alloys have the properties of high impact and fatigue strength so that they can
withstand the vibrations and the shocks during loading.
Disadvantages of Light alloy Wheels:
Magnesium alloys are prone to corrosion and therefore some protective coating has to be
given to it.
Higher cost is the biggest disadvantage of light alloy wheels compared to other wheels
mentioned above.
Aluminium alloys are used for the wheels of cars and commercial vehicles whereas the
magnesium alloy wheels are used for sports and racing cars.
This is the detailed explanation on different types of wheels. So, let's discuss about the Types of
Tyres in detailed along with its advantages.
As the name itself indicates that the wheels are divided into two halves and are joined together
by means of bolts.
While the tyre is inflated where the rims must not be seperated. The only advantage of the
divided rims wheel is that they are assembled and disassembled very easily.
5. Split Rims:
Split rims are used in larger vehicles like trucks, buses, forklifts etc. but not in cars or light
vehicles.
They are generally multi-piece wheels, where by the help of locking ring the tyre is adjusted in a
place.
This is a detailed explanation of various types of wheels. Now, let's discuss tyres and their
properties, functions, etc.
What is Tyre?
A tyre is a cushion provided within the wheel of an automobile.
Functions of Tyre:
To support the load of the vehicle.
To transmit the braking and driving forces to the road.
For smooth steering, cornering power is provided.
Properties of Tyre:
The properties of tyre are as follows.
Cushioning Effect:
The tyre should be in a position to absorb the vibrations set up by the uneven road surface by
providing cushioning effect to make the ride smoother.
Non-skidding:
This is one of the important property of the tyre which makes the vehicle not to skid even on the
wet road and this can be possible by designing a proper tread pattern on the tyre.
When the vehicle is running on uneven or even roads, the tyres experience alternating stresses
during the each revolution of the wheel. The design and the material of the tyre must be good
enough to sustain the load properly.
Uniform wear:
The non-skidding property is maintained by the uniform distribution of wear on each wheel.To
achieve this, the ribbed tread patterns will be used.
Parts of Tyre:
The parts of a tyre are as follows.
Tire belts
Tire Tread
Tire sidewall
Tire shoulder
Tire grooves
Tire bead
Tire plies
Sulfur
Carbon black
Synthetic rubber
Silica
Types of Tyre:
In general tyres are classified into two categories, those are:
As the name indicates that it has a tube within the tyre and rim assembly.
Rim
Tube
Tyre
Rim:
It is the steel material which is used to hold the tube and the tyre on it so that it can withstand the
load of the vehicle. It has a hole on its circumference to allow the tube valve through it.
Tube:
It is the material made of rubber and it consists of a valve which is pressurized by means of air so
that it can bulge according to the need and can fit into the tyre properly.
It has the disadvantage that, whenever there is a puncture then the air will be lost suddenly from
the tube, tyre and the valve region also.
Tyre:
It is the material made up of rubber and acts as the major part of automobile. The power from the
engine is to be transmitted to the wheels via axles such that the vehicle can move smoothly.
It consists of Treads separated by grooves on its circumference such that they can act as a
friction between the road and the tyre.
The tube is placed between the tyre and the rim properly such that the valve of the tube
can pass through the hole of the rim.
Then the air is pressurized into the tube up to the desired value such that it can run on the
road properly.
Make sure that the air in the tube is up to the desired value described by the
manufacturer. If the air is less, then the vehicle moves slowly.
If the driver does not know about this, then he can apply the pressure on the accelerator
so that the vehicle can move fast which decreases the fuel in the vehicle.
So the air is to be filled up properly before driving it onto the road.
2. Tubeless Tyre:
As the name indicates that it does not have a tube within the tyre and rim assembly as per the
physical structure.
But the tube is an integral part of the tyre as it is lined on inside with a special air-retaining liner
made up of halogenated butyl rubber-like bromobutyl or chlorobutyl for better air
impermeability with high heat and weather resistance.
The purpose of the bead in the tyre is to stabilize the tyre and also serve to maintain the air
pressure within.
The valve cap is used to pressurise the air into the tyre so that the vehicle moves faster.
Reduction in the air in tube or tubeless tyres reduce the mileage of the vehicle because the
system requires more effort to move the vehicle.
If the puncture happens during driving then the air loss will not takes place suddenly compared
with the tubed vehicles.
But tyre can be classified as several more ways, let me discuss those too.
First, let me show you the classifications of tyres based on Types of Carcass:
In Radial Ply tyres, the plies can run in radial direction i.e. in the direction of the axis of
the tyre.
In a circumferential direction, a number of breaker strips can run on the basic structure
and without them, the radial plies will not have lateral stability but having a soft ride.
Directional tyres
Non-directional tyres
Directional Tyres:
The directional tyres are designed in such a way that they can be rolled only in one direction.
Non-Directional Tyres:
The non-directional tyres are designed in such a way that they will perform opposite to
directional tyres i.e. they can rotate in either direction regardless of the road directions with equal
performance.
Now, let's see the main types of tyres as Conventional Tubed tyres and Tubeless tyre and are as
follws.
As in the case of a tubeless tyre, heat will be passed out to the atmosphere very easily because
there is no tube within the tyre whereas, in the case of tubed tyres, heat in the compressed air has
to pass through the tube (rubber) material which is not a good conductor of heat. Thereby the life
of the Tubeless tyres is more compared with the Tubed tyres.
Comfortable ride:
In the case of tubeless tyres, the vibrations and shocks will be absorbed at the level of tyre only.
Thus it makes the ride more comfortable.
Leakage of air:
In the case of a tubed tyre, when there is a puncture then the air will be lost suddenly from the
tube resulting in the unbalance of the vehicle. Whereas, the inner liner in the tubeless tyres is not
stretched like a tube and retains the air which results in the slower leakage.
Simpler assembly:
As there is no danger of the tyre puncture or tyre burst takes place in the tubeless tyres and Just
the tyre has to be fitted on the rim.
Brand Name: The company name will be there on the tyre. Ex: MRF, Apollo, etc.
Manufacturing Country: Whichever country manufactures that tyre, their country name
was printed on the sidewalls of the tyre.
Maximum load rating
Rim specifications
Passenger or Transport tyre
To which weather conditions, the tyre can opt.
Defects in Tyres:
Tread seperation
Bead failure
sidewall failures
continuous punctures on the same spot.
manufacturing defects
belt and tread seperation
During mounting process, the tyre may be damaged
This is a detailed explanation of Wheels and Tyres along with its types, advantages,
disadvantages, and applications. If you have any doubt, feel free to contact us from the
comments section.