Tyres Baja

Selection of Tyres for BAJA Vehicle

by

Rajesh MankarManager – Product Development

J K TYRE AND INDUSTRIES LTD

Sunday, 10th August 2008

Agenda:

History, Tyre Definition & Classification

Function of Tyre

Defining Basic Dimensions

Tyre Construction

Tyre selection criteria based on Vehicle info and performance

New Development Approach

1844 Charles Goodyear invented vulcanized rubber that was later used for tires.

1888 John Dunlop invented the air-filled or pneumatic tires for bicycles.

1895 André Michelin was the first person to use pneumatic tires on an automobile, however, not successfully.

1901 Philip Strauss invented the first successful tire, which was a combination tire and air filled inner tube.

1903 P.W. Litchfield of the Goodyear Tire Company patented the first tubeless tire,

1904 Mountable rims were introduced that allowed drivers to fix their own flats.

1908 Frank Seiberling invented grooved tires with improved road traction.

1910 B.F. Goodrich Company invented longer life tires by adding carbon to the rubber.

History Of Tyre:

What Is Tyre:

Geometrically tyre is a torus reinforced with textile cord ply / fabric or steel

carcass enclosing bead ring.

Mechanically it is a flexible membrane pressure container

Structurally it is a high performance composite

Chemically a material composed of long chain of macromolecules

TYRE SIZE DESIGNATION:

A Tyre is generally designated by its nominal cross section code followed by the nominal rim diameter code.For radial tyres,

145/80R13

Section width (mm) Aspect Ratio Nominal Rim Dia (inch)

Tyre Size Designation:

Enveloped Dimension:

145/80R13

Section Width – 145 mmAspect Ratio – 80 Rim Diameter – 13”

Aspect Ratio Section Height

Section Width

Outer Diameter = (2 x Section Height in mm) + Rim Diameter in mm

Section Height = 145*0.8 = 116 mm

Outer Diameter = (2*116) + (13*25.4) =562.2 mm

Basic Tyre Dimensions:

Tyre Section

Function Of Tyre:

Provide Load Carrying Capacity

Provide Cushioning and dampening

Transmit driving and braking torque

Provide Cornering force

Provide floatation and dimensional stability

Resist abrasion

Generate steering response

Have low Rolling Resistance

Provide minimum noise and minimum vibration

Be durable throughout and expected life spam

Tyre Construction:

BIAS RADIAL

TUBE TYPE TUBELESS

Contd…

Tyre Construction:

Cord strips are arranged diagonally to the

centerline of the tire.

Positive Qualities - strengthens the sidewall

and stabilizes the tread area for contact patch.

Negative Qualities – Builds up excessive heat;

very stiff and hard riding; get flat spots after

sitting in one spot and cooling down.

Plies are laid at 90 degree angles to centerline of tire

More sidewall movement and a smoother ride

Last longer than bias ply tires

BIAS RADIAL

Tyre Construction:

RADIAL

Tyre Construction:

BIAS

Tyre Construction:

ADVANTAGE OF RADIAL TYRES

50 - 100% LONGER LIFE - REDUCED COST PER KILOMETER

5 - 10% FUEL SAVING

PUNCTURE RESISTANT - LESS DOWN TIME

RIDING COMFORT AND REDUCED CARGO DAMAGE

EXCELLENT HIGH SPEED CAPABILITY

EXCELLENT DAMPENING OF VIBRATIONS

EXCELLENT TRACTION & BRAKING ON BOTH DRY AND WET ROAD

Tyre Construction:

Tubeless Technology

A tubeless tyre is designed with a Halobutyl liner on the inner side which is applied from bead to bead.

The Bead contour of tubeless tyres are designed to provide a self sealing mechanism between the

tyre and rim.

Lower Rolling resistance

Better handling Characteristics at high speeds

It is also reported, that air leakage after puncture

is slower in tubeless tyres than tubetype tyres thus

making tubeless tyres safer.

ADVANTAGE OF TUBELESS TYRES:

A tube Type tyre running at reduced

pressures generates more heat and is more

prone to damage.

A tube type tyre is often easier to repair in

the bush than a tubeless one, because they

are easier to remove from the rim and are

much easier to re- inflate

Tubes do not strengthen the tyre or help

prevent punctures.

Tube Type

Tyre selection criteria based on Vehicle Application and performance

Passenger Car

SUV

MUV

Light commercial Vehicle

Heavy commercial Vehicle

Based on Vehicle Application:

Based on Vehicle Dimensions / Load / Speed:

Wheel Base Tread Ground Clearance

FAW / RAW

Kerb Weight

Gross Vehicle Weight

Empty Vehicle Weight

Pay Load

Load Distribution

Tyre Selection Criteria Based on Performance:

Safety- Max. driving safety under various conditions (dry, wet, winter, etc.)

Handling-Tire Characteristics- Cornering

Economics- Mileage- Rolling Resistance

Comfort- Mechanical Comfort (flat spot)- Acoustic Comfort

Effect of component on Tyre Performance:

HYSTERESIS LOSS – Rubber

ASPECT RATIO

RIM WIDTH

TYRE SIZE

TYRE TYPE

TREAD PATTERN

TREAD RADIUS

TREAD THICKNESS

TREAD DEPTH

CORD ANGLE

NUMBER OF BODY PLIES

CONSTRUCTION

ROAD TEXTURE AND ROUGHNESS

AERODYNAMIC DRAG

NOISE

AIR CAVITY PUMPING

INFLATION PRESSURE

EFFECT OF SPEED

EFFECT OF LOAD

EFFECT OF TEMPERATURE

EFFECT OF INNER TUBE

Internal Factor External Factor

Feel the power of FEA SimulationFeel the power of FEA SimulationFeel the power of FEA SimulationFeel the power of FEA Simulation

A Simulation showing strain energy Distribution under loading

An FEA simulation revealing Inter carcass pressure acting Inside the tyre

Predictive Methods to Optimize Tyre Design:

Tyres determine to a great extent the dynamic behavior of road vehicles. Our attempt is to assist in bringing optimized synergy between the mechanical characteristics of tyre in contact with the road & the mechanics of the vehicle so that tyre-vehicle system operates safely under any circumstances & in a way that is satisfactory to the driver.

Predictive Methods to Optimize Tyre Design:

Force & Moment Test Machine

Other Methods to Optimize Tyre Design:


Rolling Resistance

Mechanical Energy converted into Heat by a tire moving for a unit distance on the roadway as a result of the rotation and the deformation of the tire

Energy Consumed per unit distance of travel as a tire rolls under load

Resistance to Motion

The amount of energy required overcoming the friction between the tyre and road surface.

The RR of a tire is responsible for

14.4% of the total vehicle energy loss.

For passenger and light truck,

Improvement in rolling resistance of

10% - Fuel efficiency increased by 0.5 ~

1.5% and for heavy truck fuel efficiency

increased by 1.5 ~ 3.0%

Contd…


% Contribution to RR

26%

2%

2%

7%

7% 8

%

48%

<2%

Tread

Belt

Inner Liner

Sidewall

Ply

Filler

Rim Strip

Bead &Chafer

Rolling Resistance

Rolling Resistance Testing Machine


Tyre Traction

Traction performance can be characterized in many ways,

including braking, acceleration, cornering, controllability,

and grade climbing. Though all factors are important, the

single best indicator of tire performance is braking distance

and deceleration.

PARAMETERPARAMETER TRACTION (WET & DRY)

TARGETTARGET IMPROVED TRACTION WITHOUT

SACRIFICING TREAD LIFE

PRIORITYPRIORITY INTERMEDIATE

PRIMARY APPROACHPRIMARY APPROACH TREAD COMPOUND OPTIMIZATION

SECONDARY APPROACHSECONDARY APPROACH CASING DESIGN OPTIMIZATION

IMPORTANTIMPORTANT TO CONTROL TENDENCY OF WANDERING & STEERING PULL WHILE BRAKING OEMs ARE EMPHASIZING THE NEED TO ACHIEVE A STABLE CONTACT PATCH WHICH DOES NOT CHANGE ITS CENTRE DURING BRAKING

LoadDirection of travel

Traction

Tyre Traction – Subjective & Objective Evaluation


Tyre Wear

Factors affecting Tyre Wear

Improper Vehicle toe, camber,caster, drive axle parallelism andperpendicularity are important factorstire wear patterns.

PARAMETER TREAD MILEAGE (WEAR)

TARGET FURTHER IMPROVEMENT REQUIRED

PRIORITY INTERMEDIATE

PRIMARY APPROACH TREAD DESIGN / DEPTH OPTIMIZATION

SECONDARY APPROACH TREAD FORMULATION OPTIMIZATIONINCREASED USE OF POLYBUTADIENE AND OPTIMIZED SOLUTION SBR

Structure Pressure Imaging and

Analysis

Pressure Mapping

Pressure Application

Foot Print Pressure Distribution study revealed

higher pressure at Shoulder blocks than at center.

Fujifilm Footprint pressure distribution study

Tyre Wear Predictive Methods:

Thermography

Measurement of surface temperature in the tyre using a thermo graphic camera and fine tuning the related parameters during the development

process

Min Temperature – 62.69Max Temperature – 72.56

T h e r m o t e k n i x VisIR 15:00:51 03/05/2004 e : 1.00 Bg : 20.0°C

-20.03

500.00

48.74

72.47Celsius

50.00

52.00

54.00

56.00

58.00

60.00

62.00

64.00

66.00

68.00

70.00

Line 1Length11

Area 1Max. Avg. Min.72.56 67.81 62.69

Img480: Line 1

Te

mp

era

ture

/ °C

Distance / Meters

48.751.153.555.858.260.663.065.467.770.172.5

0 5 10 15

Min Temperature – 58.19Max Temperature – 67.58

T h e r m o t e k n i x VisIR 15:04:21 03/05/2004 e : 1.00 Bg : 20.0°C

-20.03

500.00

45.00

70.00Celsius

50.00

55.00

60.00

65.00

Line 1Length11

Area 1Max. Avg. Min.67.58 62.97 58.19

Tyre Wear Predictive Methods:

Cornering Stiffness Testing


Tyre Ride & Handling Performance

PARAMETER RIDE & HANDLING PERFORMANCE

TARGET FURTHER IMPROVEMENT REQUIRED

PRIORITY INTERMEDIATE

PRIMARY APPROACH PATTERN DESIGN ENGINEERING (NOISE) CASING DESIGN ENGINEERING (CONSTRUCTION, MATERIALS & CONTOUR IN ORDER OF PRIORITY)

SECONDARY APPROACH TREAD COMPOUND OPTIMIZATION(INITIATION OF VERTICAL ENGINEERING IMPLEMENTATION (VEHICLE & TYRE DESIGNERS WORKING CLOSELY FROM THE INCEPTION STAGE))

Tyre Ride, Comfort & Handling Performance

Tyre Ride, Comfort & Handling Performance

Breaking StrengthStiffness Test Station

2D - Pattern3D - Model Marking

Hand Carving

Tyre testing

fitted on vehicle

Rapid Prototyping

Functional Parameters:

Rubber Compound and Chemicals: a) Natural Rubber b) Synthetic Rubber c) Carbon Black d) Silica e) Fabric f) Steel Cords


RIB PATTERN : The pattern along the circumference of the tyre

Good points : Lower rolling resistance. Good directional stability and steering control thanks to lateral resistance. Suitable for sustained high speeds thanks to low heat generation.

Bad points : Poor braking & acceleration grip on wet roads. Stress caused by flex means tread is more susceptible to cracking.

Use : For paved road surfaces and the steering wheels of trucks or buses

LUG PATTERN : The groove pattern perpendicular to the circumference of the tyre

Good points : Excellent braking & driving power. Superior traction.

Bad points : Noisy at high speed. It's not suitable for high speed driving because of high rolling resistance.

Uses : For dirt roads, rear wheels of buses, industrial vehicles and dump trucks .

Tread Pattern:


Tread Pattern:

SEMI-LUG PATTERN : The combination of Rib-shape & Lug-shape

Features : The rib in the centre provides directional control whilst the shoulder lug gives good braking & driving power.

Uses : Good for both paved and dirt roads. Usually used in both front & rear wheels of trucks and buses.

BLOCK PATTERN : The pattern of independent block which the groove is connected with each other

Good points : Good steering control and stability on snow covered and wet roads. Good water dispersal properties on wet roads.

Bad points : Tyre wear is heavy as tread blocks are finer.

Uses : Suitable for winter or all-season passenger car tyres. Suitable for back-wheel of Radial tyre of ordinary car .


Tread Pattern:

ASYMMETRIC PATTERN : Tread pattern differs on either side

Good points : Good for high speed cornering thanks to greater contact area. Reduces tread-wear on outside of tyre.

Bad points : You must position them the right way around.

Uses : High performance and motorsport tyres.

DIRECTIONAL PATTERN : Lateral grooves on both sides point the same direction.

Good points : Good driving force and braking performance. Good water dispersal means good stability on wet roads. Correct choice for fast driving styles.

Features : mounted in direction of tread pattern.

Uses : the passenger car tyre for high speed usage.


TreadBelt and BreakersCap Ply/ Prot Ply CarcassSide WallBeadChaferFiller

Tyre Components:


Tread

Tread is the wear resistance component of the tyre, when it is contacting with the road. It must also provide traction, wet skid and good cornering characteristics with minimum noise generation and low heat buildup. It is the part through which braking, driving and cornering forces are transmitted.

These are short plies of rubber coated steel cut at an angle and are positioned centrally between the tyre casing and tread to strengthen carcass against impacts.

Belts

Cap Ply

It is placed in the crown area just below the tread rubber. It provides cut resistance protection to the underlying belts and carcass plies.Enhances high-speed suitability.


Carcass

Rubber bonded cord structure of a tyre integral with the bead, which provides the required strength to carry load.

Sidewall

Part of the tyre between bead and tread which flexes in service. Protects the casing from side scuffing, control vehicle and ride characteristics and assist in tread support

Bead Core

A bead should hold the tyre against the rim and should avoid the movement of the tyre relative to rim. The shape and contour of the bead conforms to the flange of the rim, thus preventing from rocking or slipping on to the rim.


Filler

Chafer

Gives steering precisionImproves comfort

To prevent chafing action between bead and rim. Their purpose is to protect the carcass plies from damage when mounting or dismounting and to reduce the effects of wear and chafing between the wheel and thetire bead

Thank You

[email protected]

09971492958

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Tyres Baja