This document discusses the components and specifications of tires. It describes various tire parts like the tread, sidewall, beads, and materials like cords and elastomers. It provides information on tire ratings for load, speed, and service. Wheel alignment and conditions that affect tire wear like improper inflation pressure or misalignment are also covered. Retreading worn tires is discussed as a way to make commercial vehicle tires more economical.

1. BHARATH UNIVERSITY
DEPARTMENT OF AUTOMOBILE ENGINEERING
DONE
BY
UMA SHANKAR. S (U12AM041)
PRADEEP. S (U12AM027)
PRABHANJAN.R.P (U12AM026)
ARUN KUMAR. M (U12AM005)
JAYANTH (U12AM015)
VIJAY. P (U12AM043)

2.  INTRODUCTION
 HISTORY
 MATERIALS AND COMPONENTS
 SPECIFICATIONS
 TYRE WEAR
 PERFORMANCE CHARACTERISTICS
 MARKINGS
 VEHICLE APPLICATIONS
 SAFETY AND PRECAUTIONS
 CONCLUSION
 REFERENCE

3.  A tyre (American English) or tyre (British English), is a ring-shaped
vehicle component that covers the wheel's rim to protect it and enable
better vehicle performance. Most tires, such as those for automobiles and
bicycles, provide traction between the vehicle and the road while providing
a flexible cushion that absorbs shock.
 The spelling tyre does not appear until the 1840s when the English began
shrink fitting railway car wheels with malleable iron. Nevertheless,
traditional publishers continued using tire. The Times newspaper in Britain
was still using tire as late as 1905. The spelling tyre, however, began to be
commonly used in the 19th century for pneumatic tires in the UK.
 Another origin of "tire" is provided by Online Etymology
Dictionary, essentially that the word is a short form of "attire," and that a
wheel with a tire is a dressed wheel. Some other etymologists may share
this view.

4.  Historically, the spelling was "tire" and is of French origin, which comes from the
word tirer, to pull. The reason for this naming is that originally "tire" referred to
iron hoops or thick wires bound to carriage wheels. In French blacksmithing the
word for a drawn iron rod is a tirer, or pull. The same word was often used for any
metal drawing or rolling process. In an article in the London
Magazine/Intelligencer of 1853 "The Utility of Broad Wheels," it explains that the
common practice was to bend two rods, called "tires," into hoops and bind them to
the wheel, but it is preferable to use an iron band, called a "broad wheel" rather
than the rods, because as the rods wear they bite into the wheel. Another early
mention of a tire in English is in The Scots Magazine, Volume 15 By James
Boswell (1753).
 The 1911 edition of the Encyclopedia Britannica states that "[t]he spelling 'tyre' is
not now accepted by the best English authorities, and is unrecognized in the
US", while Fowler's Modern English Usage of 1926 says that "there is nothing to
be said for 'tyre', which is etymologically wrong, as well as needlessly divergent
from our own [sc. British] older & the present American usage". However, over the
course of the 20th century tyre became established as the standard British spelling.

5.  In 1892 Dunlop's patent was declared invalid because of prior
art by forgotten fellow Scot Robert William Thomson of
London (patents London 1845, France 1846, USA 1847),
although Dunlop is credited with "realising rubber could
withstand the wear and tear of being a tire while retaining its
resilience". J B Dunlop and Harvey du Cros together worked
through the ensuing considerable difficulties. They employed
inventor Charles Kingston Welch and also acquired other
rights and patents which allowed them to protect their
business's position. The development of this technology
hinged on myriad engineering advances. In terms of materials,
the vulcanization of natural rubber which he patented in 1844
is credited to Charles Goodyear and Robert William Thomson.

6.  Cords
 Elastomer
 Treads
 Tread lug
 Tread void
 Rain groove
 Sipe
 Wear bar
 Bead
 Sidewall
 Shoulder
 Ply

7. CORDS
The cords, which form the ply and bead and provide the tensile strength necessary to contain
the inflation pressure.
ELASTOMETER
The elastomer, which forms the tread and encases the cords to protect them from abrasion and
hold them in place.
TREADS
The tread is the part of the tire that comes in contact with the road surface. The portion that is
in contact with the road at a given instant in time is the contact patch.
TREAD LUG
Tread lugs provide the contact surface necessary to provide traction. As the tread lug enters
the road contact area, or footprint, it is compressed.
TREAD VOID
Tread voids provide space for the lug to flex and deform as it enters and exits the footprint.
Voids also provide channels for rainwater, mud, and snow to be channeled away from the
footprint.

8. RAIN GROOVE
The rain groove is a design element of the tread pattern specifically arranged to channel water
away from the footprint. Rain grooves are circumferential in most truck tires.
SIPE
Tread lugs often feature small narrow voids, or sipes, that improve the flexibility of the lug to
deform as it traverses the footprint area. This reduces shear stress in the lug and reduces heat
build up.
WEAR BAR
Wear bars (or wear indicators) are raised features located at the bottom of the tread grooves
that indicate the tire has reached its wear limit.
BEAD
The bead is the part of the tire that contacts the rim on the wheel. The bead is typically
reinforced with steel wire and compounded of high strength, low flexibility rubber. The bead
seats tightly against the two rims on the wheel to ensure that a tubeless tire holds air without
leakage.

9. SIDE WALL
The sidewall is that part of the tire that bridges between the tread and bead. The
sidewall is largely rubber but reinforced with fabric or steel cords that provide for
tensile strength and flexibility.
SHOULDER
The shoulder is that part of the tire at the edge of the tread as it makes transition to
the sidewall.
PLY
Plies are layers of relatively inextensible cords embedded in the rubber to hold its
shape by preventing the rubber from stretching in response to the internal pressure.

10. WHEEL
Tires are mounted onto wheels that most often have integral rims on their outer
edges to hold the tire. Automotive wheels are typically made from pressed and
welded steel, or a composite of lightweight metal alloys, such as aluminum or
magnesium. The mounted tire and wheel assembly is then bolted to the
vehicle's hub. A decorative hubcap and trim ring may be placed over the wheel
RIM
The beads of the tire are held on the rim, or the "outer edge" of a wheel. These
outer edges are shaped to obtain a proper shape on each side, having a radially
cylindrical inclined inner wall on which the tire can be mounted. Tires are mounted
on the wheel by forcing its beads into the channel formed by the wheel's inner and
outer rims.

11. INNER TUBE
Most bicycle tires, many motorcycle tires, and many tires for large vehicles such as
buses, heavy trucks, and tractors are designed for use with inner tubes. Inner tubes
are torus-shaped balloons made from an impermeable material, such as soft, elastic
synthetic rubber, to prevent air leakage. The inner tubes are inserted into the tire
and inflated to retain air pressure.
VALVESTEM
The valve stem is a tube made of metal or rubber, through which the tire is inflated,
with a check valve, typically a Schrader valve on automobiles and most bicycle
tires, or a Presta valve on high-performance bicycles. Valve stems usually protrude
through the wheel for easy access.

12. TIRE PRESSURE MONITORING SYSTEM
Tire pressure monitoring systems (TPMS) are electronic systems that monitor the
tire pressures on individual wheels on a vehicle, and alert the driver when the
pressure goes below a warning limit. There are several types of designs to monitor
tire pressure.
INFLATION PRESSURE
Tires are specified by the vehicle manufacturer with a recommended inflation
pressure, which permits safe operation within the specified load rating and vehicle
loading. Most tires are stamped with a maximum pressure rating. The effectiveness
of the use of nitrogen vs. air as a means to reduce the rate of pressure loss is
baseless, and has been shown to be a bogus marketing gimmick One study noted a
1.3 psi (9.0 kPa; 0.090 bar) difference (from an initial pressure of 30 psi (210 kPa;
2.1 bar)) for air-filled vs. nitrogen-filled tires. However, the statistical significance
of the purported 1.3 psi (9.0 kPa; 0.090 bar) difference in the latter study is
questionable, since no t-test nor p values were reported.

13. LOAD RATING
Tires are specified by the manufacturer with a maximum load rating. Loads
exceeding the rating can result in unsafe conditions that can lead to steering
instability and even rupture. For a table of load ratings, see tire code.
SPEED RATING
The speed rating denotes the maximum speed at which a tire is designed to be
operated. For passenger vehicles these ratings range from 160 to 300 km/h (99.4 to
186 mph). For a table of speed ratings, see tire code.
SERVICE RATING
Tires (especially in the U.S.) are often given service ratings, mainly used on bus
and truck tires. Some ratings are for long haul, and some for stop-start multi-drop
type work. Tires designed to run 500 miles (800 km) or more per day carrying
heavy loads require special specifications.

14. WHEELALIGNMENT
Wheel alignment is the procedure for checking and correcting this condition
through adjustment of camber, caster and toe angles. These settings also affect the
handling characteristics of the vehicle.
RETREAD
Tires that are fully worn can be re-manufactured to replace the worn tread. This is
known as retreading or recapping, a process of buffing away the worn tread and
applying a new tread. Retreading is economical for truck tires because the cost of
replacing the tread is less than the price of a new tire.
Many commercial trucking companies put retreads only on trailers, using only new
tires on their steering and drive wheels. This procedure increases the driver’s
chance of maintaining control in case of problems with a retreaded tire.

15. CAUSE AND CONSEQUENCES
Consequences of wheel positions deviations
 Premature tyre wear and the causes
 Poor steering characteristics
 Vibration of the vehicle
Premature tyre wear and the causes
Abnormal or too fast tyre wear originates when irregularities
or defects occur to the wheel, the tyre or the vehicle. Other
causes of too fast tyre wear are incorrect use of the vehicle and
poor maintenance.

17. Under inflations will cause wear on the
shoulders of tire. Over inflation cause wear at
the center of tyre. Excessive camber causes the
tyre to run at an angle to the road. One side of
thread is then worn more than the other
.excessive toe-in or toe-out causes wear on
the thread edges and a feathered effect across
the thread.

18. standard tyre wear drawings , possible causes of uneven or
accelerated tyre wear:
If the thread wear is even, but the tyre is wearing quickly , this may be
caused by driving at too high speed or driving in a warm in a warm climate
with tyres made of unsuitable rubber.
Tyre efficiency as a result of tyre pressure and load:
The consequences for the life can be seen for a tyre that is 20% overloaded.
The life of the tyre is then decreased by up to 70% if the tyre has 20%
under pressure the life of the tyre decreases by up to 74%.

19. influence of speed on the life of a tyre:
The influence of speed and the ambient temperature is shown. If , for
example, efficiency at a speed of 64 kmph and a temperature of 190 C is
100% this efficiency fall to 55% at as speed of 112 kmph . The life of the
tyre accordingly decreases by 45%.
one –sided tyre ward:
Single –sided tread wear is usually caused by an incorrect camber. The
wheel is then out of square on the road surface. With the deformation of
the tyre the wheel turns on different circumferences. One side wilt slip and
result in shoulder wear without ridge formation.

20. serrated wear:
Serrated wear in the longitudinal direction of the tyre is common on non-
driven axles. Because the separate features of the tyre tread forming tread
design are not driven but do deform, they wear more quickly on the one
side than the other.
Vertical and lateral run-out in tyre combinations:
It is possible for the wheel to still vibrate after balancing.the cause can be
vertical run-out or lateral run-out. Vertical run-out is the up and down
movement of the axle pf the turning wheel due to out-of-roundness. Lateral
run-out is a consequence of the askew position of the tyre on the tyre on
the rim due to dirt between heel and rim edge or the poor fitting the heel.
Lateral run-out can also occur after a wheel is fitted on a car. The cause is
then askew assembly on the axle due to damage or dirt.

21. Balance
When a wheel and tire rotate, they exert a centrifugal force on the axle that
depends on the location of their center of mass and the orientation of
their moment of inertia. This is referred to as balance, imbalance, or
unbalance. Tires are checked at the point of manufacture for excessive
static imbalance and dynamic imbalance using automatic tire balance
machines.
Circle of forces
The circle of forces, traction circle, friction circle, or friction ellipse is a
useful way to think about the dynamic interaction between a vehicle's tire
and the road surface.

23. STOPPING DISTANCE:
Performance-oriented tires have a tread pattern and rubber compounds
designed to grip the road surface, and so usually have a slightly shorter
stopping distance. However, specific braking tests are necessary for data
beyond generalizations.

24. INTERNAL FACTOR EXTERNAL FACTOR
Aspect Ratio Road texture and roughness
Rim width Aerodynamic drag
Tyre size Effect of speed
Tyre pattern Effect of load
Tread depth Effect of temperature
Cord angle Effect of inner tube
EFFECT OF COMPONENT ON TYRE PERFORMANCE

25. DOT Code:
In the United States, the DOT Code is an alphanumeric character sequence
molded into the sidewall of the tire for purposes of tire identification. The
DOT Code is mandated by the U.S. Department of Transportation. The
DOT Code is useful in identifying tires in a product recall.
E-mark:
All tires sold for road use in Europe after July 1997 must carry an E-mark.
The mark itself is either an upper case "E" or lower case "e" – followed by
a number in a circle or rectangle, followed by a further number. An (upper
case) "E" indicates that the tire is certified to comply with the dimensional,
performance and marking requirements of ECE regulation 30.

26. MODEL SERIAL NUMBER:
Tire manufacturers usually embed a mold serial number into
the sidewall area of the mold, so that the tire, once molded,
can be traced back to the mold of original manufacturer.

27. SIZE CODES:
Automobile tires are described by an alphanumeric code, which is
generally molded into the sidewall of the tire. This code specifies the
dimensions of the tire, and some of its key limitations, such as load-bearing
ability, and maximum speed. Sometimes the inner sidewall contains
information not included on the outer sidewall, and vice versa

29. Passenger vehicles and light truck
High performance
 High performance tires are designed for use at higher
speeds, and more often, a more "sporty" driving style. They
feature a softer rubber compound for improved traction,
especially on high speed cornering. The trade off of this softer
rubber is shorter tread life.
 High performance street tires sometimes sacrifice wet weather
handling by having shallower water channels to provide more
actual rubber tread surface area for dry weather performance.

31. MUD AND SNOW
Mud and Snow, (or M+S, or M&S), is a designation applied rather
arbitrarily by manufacturers for all-season and winter tires designed to
provide improved performance under low temperature conditions,
compared to summer tires. Tires may have well above average numbers of
sipes in the tread pattern to grip the ice. There are no traction performance
requirements which such a tire has to meet; M&S relates to the percentage
of tread void area.
Mud tires are specialty tires with large, chunky tread patterns designed to
bite into muddy surfaces. The large, open design also allows mud to clear
quickly from between the lugs. Mud terrain tires also tend to be wider than
other tires, to spread the weight of the vehicle over a greater area to prevent
the vehicle from sinking too deeply into the mud.

32. ALL SEASON:
The all-season tire is a compromise, and is neither an excellent summer tire
nor an excellent winter tire. All-Season tires are also marked for mud and
snow the same as winter tires but rarely with a snowflake. Owing to the
compromise with performance during summer, winter performance is
usually poorer than a winter tire.
ALL TERRAIN:
All-terrain tires are typically used on SUVs and light trucks. These tires
often have stiffer sidewalls for greater resistance against puncture when
traveling off-road, the tread pattern offers wider spacing than all-season
tires to remove mud from the tread. Many tires in the all-terrain category
are designed primarily for on-road use, particularly all-terrain tires that are
originally sold with the vehicle.

33. Light trailer
Domestic Trailers (including camping trailers) for use on public highways
often have different tires than those seen on cars. Often they are bias
ply rather than radial tires, and they often don't have as aggressive a tread
pattern as standard road tires.
Off-the-road
Off-the-road (OTR) tires include tires for construction vehicles such as
wheel loaders, backhoes, graders, trenchers, and the like; as well as large
mining trucks. OTR tires can be of either bias or radial construction
although the industry is trending toward increasing use of radial. Bias OTR
tires are built with a large number of reinforcing plies to withstand severe
service conditions and high loads.

34. Racing
Racing tires are highly specialized according to vehicle and race
track conditions. This classification includes tires for drag racing, Auto-x,
drifting, Time Attack, Road Racing – as well as the large-market race tires
for Formula One, IndyCar, NASCAR, V8 Supercars, WRC, MotoGP and
the like. Racing tires often are engineered to minimum weight targets, so
tires for a 500-mile (800 km) race may run only 100 miles (160 km) before
a tire change. Racing tires often are not legal for normal highway use.
Industrial
The Industrial tire classification is a bit of a catch-all category and includes
pneumatic and non-pneumatic tires for specialty industrial and construction
equipment such as skid loaders and fork lift trucks.

35. BICYCLE
This classification includes all forms of bicycle tires, including road racing
tires, mountain bike tires, snow tires, and tubular tires, used also with other
human-powered vehicles (see Category: Human-powered vehicles).
AIRCRAFT
Aircraft tires are designed to withstand extremely heavy loads for short
durations. Aircraft tires generally operate at high pressures, up to
200 pounds per square inch (14 bar; 1,400 kPa) for airliners, and even
higher for business jets. Tests of airline aircraft tires have shown that they
are able to sustain pressures of maximum 800 pounds per square inch
(55 bar; 5,500 kPa) before bursting.

36. Proper vehicle safety requires specific attention to inflation pressure,
tread depth, and general condition of the tires. Over-inflated tires run the
risk of explosive decompression (they may pop). On the other hand, under-
inflated tires have a higher rolling resistance and suffer from overheating
and rapid tread wear particularly on the edges of the tread.
Tires worn down past their safety margins and into the casing run the very
real risk of rupturing. Also, certain combinations of cross ply and radial
tires on different wheels of the same vehicle can lead to vehicle instability,
and may also be illegal. Vehicle and tire manufacturers provide owner’s
manuals with instructions on how to check and maintain tires.

37. SIZE 14.00R 20 12.00R 20
PRESSURE 20 18 18 16
PATTERN CODE HP 10/ HP 11 HP 10/ HP 11 HP 10 HP 10
RIM 10.0.20 10.0.20 8.5.20 8.5.20
DIMENSION OUT
DIAMETER
1232 1232 1122 1122
SECTION
WIDTH
375 375 315 315
DIAMETER
UNDER
DYNAMIC
LOAD
579 579 526 526
BASIC DATA LOAD
INDEX
164 161 154 152
Kg LOAD 5000 4625 3750 3250
Kpa AIR
PRESSURE
790 690 830 770
SPEED G (90 Km/h) K (110 Km/h)
SAFETY PERFORMANCE MORE THAN 100 KM AFTER AIR - DEFLATION

38. FLAT
A flat tire occurs when a tire deflates. This can occur as a result of normal
wear-and-tear, a leak, or more serious damage.A flat tire or low-pressure
tire should be considered an emergency situation, requiring immediate
attention. Some tires, known as "run-flat tires", have either extremely stiff
sidewalls or a resilient filler to allow driving a limited distance while flat,
usually at reduced speed, without permanent damage or hazard.

39. BUBBLE
Tire bubbles, also referred to as bulges / bumps / protrusions / carbuncles,
occur when the sidewall of the tire has failed, resulting in a protrusion.
Causes of bubbles include having an impact at high speed, over inflation,
or poor tire construction/manufacturing. It is generally recommended to
replace the tire since the probability of tire failure has increased. They can
occur on the inner or outer sidewall.

40. HYDROPLANNING
Hydroplaning, also known as aquaplaning, is the condition where a layer of
water builds up between the tire and road surface. Hydroplaning occurs
when the tread pattern cannot channel away enough water at an adequate
rate to ensure a semi-dry footprint area. When hydroplaning occurs, the tire
effectively "floats" above the road surface on a cushion of water – and
loses traction, braking and steering, creating a very unsafe driving
condition.
DANGER OF AGED TIRES
Research and tests show that as tires age, they begin to dry out and become
potentially dangerous, even if unused. Aged tires may appear to have
similar properties to newly manufactured tires, but rubber degrades over
time, and once the vehicle is traveling at high speeds (i.e. on a freeway) the
tread could peel off, leading to severe loss of control.

41. Also, tires on seldom-used trailers are at the greatest risk of age-failure, but
some tires are built to withstand idleness, usually with nylon
reinforcement.
Many automakers recommend replacing tires after six years, and several
tire manufacturers (Bridgestone, Michelin) have called for tires to be
removed from service 10 years after the date of manufacture.

42. Scrap tires and environmental issues
Once tires are discarded, they are considered scrap tires. Scrap tires are
often re-used for things from bumper car barriers to weights to hold down
tarps. Some facilities are permitted to recycle scrap tires through chipping,
and processing into new products, or selling the material to licensed power
plants for fuel.
The use of scrap tire chips for landscaping has become controversial, due
to the leaching of metals and other contaminants from the tire pieces. Zinc
is concentrated (up to 2% by weight) to levels high enough to be highly
toxic to aquatic life and plants. Of particular concern is evidence that some
of the compounds that leach from tires into water, contain hormone
disruptors and cause liver lesions.

43. Flexible sidewalls, Reduced fuel consumption due to less rolling
resistance. A softer ride because of the layout of the tire's plies and because
of the flex of the sidewalls, assuring more stable contact with the road
service and a softer ride. Less vibration, Extended tire life due to less heat
generated by the tire.
Poor transport handling, since low lateral stiffness causes the tire sway to
increase as the speed of the vehicle increases. Increased vulnerability to
abuse when overloaded or under-inflated. The sidewall tends to bulge
which could cause damage and puncture. A ply layout that causes the radial
tire to follow a wheel track more consistently than a bias ply tire. The
radial tire is more expensive than a bias ply tire which may be considered
as a disadvantage.

44.  Jump up^ See spelling differences
 Jump up^ http://www.etymonline.com
 Jump up^ Peters, Pam (2004). The Cambridge Guide to English Usage. Cambridge University Press. p. 553. ISBN 978-
0-521-62181-6.
 Jump up^ Chisholm, Hugh, ed. (1911). Encyclopædia Britannica, vol. 26. Encyclopædia Britannica. p. 1007.
 Jump up^ Fowler, H. W.; David Crystal (ed.) (2009). A Dictionary of Modern English Usage: The Classic First Edition.
Oxford University Press. p. 655. ISBN 978-0-19-953534-7. Retrieved 2010-10-23.
 Jump up^ Bertman, Stephen (2005). p.35 Handbook to Life in Ancient Mesopotamia. Oxford University Press.
Retrieved 2 August 2014.
 Jump up^ Sir Arthur Du Cros, Bt, Wheels of Fortune, a salute to pioneers, Chapman & Hall, London 1938
 Jump up^ Dunlop, John Boyd (2008). Hutchinson Dictionary of Scientific Biography. AccessScience. Retrieved 9
July 2009.
 ^ Jump up to:a b Werner Obrecht, Jean-Pierre Lambert, Michael Happ, Christiane Oppenheimer-Stix, John Dunn and Ralf
Krüger "Rubber, 4. Emulsion Rubbers" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH,
Weinheim. doi:10.1002/14356007.o23_o01
 Jump up^ Samuel K. Clark, V. E. Gough (1981). Mechanics of Pneumatic Tires. U.S. Department of Transportation.
p. 245. Consider two mechanisms of force transmission acting in parallel.
 ^ Jump up to:a b Samuel K. Clark, V. E. Gough (1981). Mechanics of Pneumatic Tires. U.S. Department of
Transportation. p. 246. The only possible way in which the reaction can develop at the rim is by the changes in
magnitude and direction of the membrane stresses at their points of attachment to the rim, in the region of the membrane
near the point where the plate is pressed against it.
 Jump up^ Samuel K. Clark, V. E. Gough (1981). Mechanics of Pneumatic Tires. U.S. Department of Transportation.
p. 246. This force pulls the bead coil against the base of the wheel rim above the contact area, thus transmitting the
upward force to the wheel.