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:
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 mm Aspect Ratio – 80 Rim Diameter – 13” 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 Aspect Ratio Section Height Section Width
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
T yre 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
Gross Vehicle Weight
Empty Vehicle Weight
Tyre Selection Criteria Based on Performance: Safety - Max. driving safety under various conditions (dry, wet, winter, etc.)
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
AIR CAVITY PUMPING
EFFECT OF SPEED
EFFECT OF LOAD
EFFECT OF TEMPERATURE
EFFECT OF INNER TUBE
Internal Factor External Factor
Feel 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:
Tyre Selection Criteria Based on Performance: 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…
Tyre Selection Criteria Based on Performance: Rolling Resistance
Tyre Selection Criteria Based on Performance: 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. 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 IMPORTANT CASING DESIGN OPTIMIZATION SECONDARY APPROACH TREAD COMPOUND OPTIMIZATION PRIMARY APPROACH INTERMEDIATE PRIORITY IMPROVED TRACTION WITHOUT SACRIFICING TREAD LIFE TARGET TRACTION (WET & DRY) PARAMETER Load Direction of travel Traction
Tyre Traction – Subjective & Objective Evaluation
Tyre Selection Criteria Based on Performance: Tyre Wear Factors affecting Tyre Wear Improper Vehicle toe, camber, caster, drive axle parallelism and perpendicularity are important factors tire wear patterns.
TREAD FORMULATION OPTIMIZATION
INCREASED 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:
T hermography Measurement of surface temperature in the tyre using a thermo graphic camera and fine tuning the related parameters during the development process Min Temperature – 62.69 Max Temperature – 72.56 Min Temperature – 58.19 Max Temperature – 67.58 Tyre Wear Predictive Methods:
Tyre Selection Criteria Based on Performance: Tyre Ride & Handling Performance TREAD COMPOUND OPTIMIZATION (INITIATION OF VERTICAL ENGINEERING IMPLEMENTATION (VEHICLE & TYRE DESIGNERS WORKING CLOSELY FROM THE INCEPTION STAGE))
PATTERN DESIGN ENGINEERING (NOISE)
CASING DESIGN ENGINEERING (CONSTRUCTION, MATERIALS & CONTOUR IN ORDER OF PRIORITY)
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.
Functional Parameters: Tread Belt and Breakers Cap Ply/ Prot Ply Carcass Side Wall Bead Chafer Filler Tyre Components:
Functional Parameters: 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.
Functional Parameters: 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.
Functional Parameters: Filler Chafer Gives steering precision Improves 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 the tire bead