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Types of tyresBelu Mihai 1711 AE

Scottish veterinarian John Boyd Dunlop invented the first air-filled or pneumatic tyres in 1888. He

attached rubber hoses to wooden wheels and covered the contact patches with thick canvas. He placed

these first tyres on a tricycle and took a test run. Finding no problems, Dunlop then attached rubber

pieces to the canvas in order to prevent skidding and tested these tyres on a bicycle. The result was a

success and this marked the beginning of pneumatic

tyres.

The bead wire tyre invented by C.K. Welch in 1891 marks an important breakthrough in tyre history.

That same year, the Michelin brothers patented tyres that could be mounted or demounted by hand. In

1904, Firestone and Goodyear Tyre Company developed straight sided wire bead tyres and almost all

the tyre manufacturers in the US were following their manufacturing techniques by 1908.

Meanwhile in 1913, Britain developed the radial ply method which broke from the previous bias ply

method which used tyre code fabric. However, the radial ply method only came into wide use some 35

years later, in 1948, when it was adopted by Michelin. The code fabric was made from a weave of thick

cotton thread. Due to high prices, the stronger silk thread could not be used in manufacturing tyre code

fabric. However, in 1928, US firm Dupont created the basic theory of synthetic reactions which resultedin rapid developments in the 1930s. Prior to 1948, rayon code fabric improved upon the heat -

susceptive cotton code fabric and took 75% of the market share.

1948 saw the invention of nylon code fabric which competed with rayon until 1959. Nylon eventually

won the price competition in 1960 and began to dominate the market. A new polyester code fabric

debuted in 1962. In the 1970s, steel codes took the lead and swept the European and US markets in the

1980s. In 1972, Dupont invented a polyamide fibre called Kevlar, five times stronger that steel with

good dimensional stability, but it was so expensive that its use was limited to tyres for select passenger

cars.

In this way, the development of materials and manufacturing technology along with the increase in

automobile performance together set the stage for a focus on the dynamic capabilities of tyres. In

particular, to parallel the development of roads and cars, passenger car tyres have been designed to

deliver enhanced speed, control and safety. New economic, high performance tyres continue to be

developed. Along with cars, tyres have shown outstanding development in aspect ratios and top driving

speeds.

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Functions of the tyres :

Tyres play an important role as an automobile component. Many parts may make up a car but

usually one part is limited to one function. Despite its simple appearance, a tyre differs from other partsin that it has numerous functions. Thus, a tyre supports the weight of the car, reduces the impact from

the road and at the same time, transmits the power to propel, brake and steer on the road. It also

functions to maintain a cars movement. In order to complete such tasks, a tyre must be structured to

be a resilient vessel of air.

A tube is used to maintain its major function of maintaining air pressure but a tube alone cannot

maintain the high pressure needed to withstand the great weight. In addition, the tube lacks the

strength to withstand all of the exterior damage and impact from driving on the road.

The carcass is entrusted with this function.The carcass is an inner layer that protects the tube that

contains the high-pressure air and supports vertical load. A thick rubber is attached to the parts that

meet the road to withstand exterior damage and wear. Tread patterns are chosen according to car

movement and safety demands. A solid structure is necessary to make sure the tyres are securely

assembled onto rims.

According to improvements in automobile quality and capability as well as the diversification of usage,

the capabilities and performance of tyres are becoming more complex and diversified.

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Classification according to vehicle

1. PCpassenger car tyre 5. AGagricultural tyre

2. LTlight truck tyre 6. IDindustrial tyre

3. TBtruck and bus tyre 7. MCmotocycle tyre

4. OTRoff the road tyre 8. ACair craft tyre

Classification according to structure

1. Bias TyreLayers of one ply cord material are placed on the tyre carcass diagonally from one tyre bead to the other

at angles of about 40 to the centerline of the tread. The lengthy research and development period have

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given this tyre an overall steady performance and stiff sidewall. With the advent of the radial tyre

however, the bias tyre is now used much less frequently.

2. Radial Tyre

A radial tyre uses a cord angle of 90 degrees. That is, the cord material runs in a radial or direct line from

one bead to the other across the tread. In addition, a radial tyre has a belt overwrap under the tread

surface to provide greater structural stability. The belt overwrap of a radial tyre distortion while the

radial structure enables high speed driving.

3. Belted Bias Tyre

A radial tyre-like belt is attached to a bias tyre carcass. The belt increases the stiffness of the improves

traction for better steering and stability. However, the belted bias tyre is generally product from the

transition of a bias structure to radial structure and is not widely used.

4. Tubeless Tyre

As cars became faster, the tubeless tyre was developed to protect drivers and cars from the dangers of

flat tyre accidents while driving at high speeds. Instead of using a tube, a lining (inner liner) of special

rubber with low air permeability inside the tyre prevents air leaks from the tyre and rim. This means that

even if a nail punctures the tyre while on the move, air pressure will not be lost very rapidly. However,

careful tyre maintenance is still necessary as there is no tyre that does not go flat. In addition, there are

tubeless tyres that use airtight, highly binding cement on the inside of the inner liner to decrease air

leakage even further.

Advantages of a Tubeless Tyre

- Maintains air pressure

- Sudden air leakage does not occur even with puncture

- Improved heat emission while driving because air inside the tyre is in direct contact with rim

- Less maintenance or mishaps with tube

- Increased operation efficiency with no tube assembly

Disadvantages of a Tubeless Tyre

- Separation occurs if crack appears inside tyre bead

- Air leakage in the case of imperfect tyre-rim assembly or disfiguration

in the rim flange. In particular, caution is needed when driving on unpaved roads as rocks and other

debris may damage the rim flange and cause air leakage.

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Classification according to season

1. Summer Tyre

As a tyre for use in seasons without snow (spring, summer, fall), the summer or general tyre is optimized

for reduced noise, smooth driving and safe handling at high speeds.

2. All Season Tyre

Developed to relieve the difficulty of changing from summer tyres to winter ones in regions with short

snow seasons, the all season has more tread kerfs than the summer tyre.

Classification According to Vehicle

1. Regular Tyre

Also called a ground tyre that is not for emergency use.

2. All Season Tyre

When a regular tyre has been damaged by a flat or other reason and cannot be used, the emergencytyre may be used temporarily. Emergency tyres can save trunk space and reduce the weight of the car.

There are two types of emergency tyres:

a. Foldable emergency tyres

b. T-type emergency tyres

Emergency tyres are manufactured only for use in emergencies and cannot be used at speeds of over

80km/h. The pneumatic pressure has to be maintained at 60psi and the air pressure should be checked

at least once a month.

3. Run Flat Tyre

Even when the air pressure within the tyre reaches zero due to damage such as a flat, this tyre can be

used to drive 80km at 80km/h speed to a location where a tyre change can be made.

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Classification According to Pattern

With the exception of certain special tyres, various characteristics exist for tyre treads (the part of the

tyre that meets the road). These characteristics are becoming more complicated as applications growmore diverse with the development of roads and vehicles.

Requirment Function

Performance

Improved driving and braking power

Prevention of side slippage

Steering safety

Increased economy (reduced wear, gas cost)

Resistance against heat generation by tyres

Decreased noise, enhanced ride

External appearance Improved product value

1. Kerf and Sipe

Kerfs and sipes are small slots molded into treads to improve braking capability or prevent. They are

particularly useful on wet road surfaces.

Kerfs are shallow slits on the tyre tread made by placing a blade-shaped implement in the tyre mold.

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When stronger braking capability is desired, a tyre is placed on a siping machine. Small cuts spaced 1

mm apart are made in the lateral direction of the tyre. Nowadays, siping is not performed frequently as

many kerfs are sculpted into molds.

Type Pattern characteristics Ex. of basic pattern Main application

Rib

Advantages

Low rolling resistance

and heat generation

High resistance to side

slippage, good

steering and safety

Less vibration and goodrideness

Disadvantages

Relatively lower

braking, driving power

Grooves are sensitive to

fatigue

Paved roads, high

speeds

Mainly used forpassenger cars and

buses as well as light

trucks

Lug

Advantages

Good driving, braking

power

Good for unpaved roads

Disadvantages

Relatively higher rolling

resistance

(low fuel economy)

Relatively greater noise

Relatively lower

registance to side

slippage

Regular roads, unpaved

roads

Used for trucks, buses,

light trucks. Most

construction vehicles

and industrial vehicles

use the lug type

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Rib-lug

Advantages

Good steering

and safety due to use of

both rib and lug

patterns

Good forvehicles that use both

paved and

unpaved roads

Disadvantages

Greater wear

on ends of lugs

Rips in ribgrooves

Lower driving,

braking power than lugtype

Paved, unpaved roads

Used for trucks, buses

Block

Advantages

Good propulsion,

braking

Good braking, steering,

safety good in

snow & mud

Disadvantages

Wears faster than rib or

lug typesHigh rolling resistance

Snow tyre

Used for sand service

vehicles

Asymmetrical

Advantages

Uniform contact area

Good wear and braking

No need to rotate tyres

Disadvantages

Not in much use

Little compatibility with

other sizes

Passenger use tyre(high

speed)

Some trucks