The document discusses the selection of tires for BAJA vehicles. It provides a brief history of tire development. It then discusses tire definitions, components, construction methods, selection criteria based on vehicle type and performance, and new development approaches including simulation and testing methods. The key factors considered for tire selection include safety, handling, economics, comfort, rolling resistance, traction, wear and ride/handling performance. Predictive methods like FEA simulation and various tests are used to optimize tire design.

1. Selection of Tyres for BAJA Vehicle by Rajesh Mankar Manager – Product Development J K TYRE AND INDUSTRIES LTD Sunday, 10th August 2008

3. 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:

5. 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

6. Basic Tyre Dimensions: Tyre Section

8. Tyre Construction: BIAS RADIAL TUBE TYPE TUBELESS Contd…

10. Tyre Construction: RADIAL

11. Tyre Construction: BIAS

14. T yre selection criteria based on Vehicle Application and performance

15. Passenger Car SUV MUV Light commercial Vehicle Heavy commercial Vehicle Based on Vehicle Application:

19. 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:

20. 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:

21. Force & Moment Test Machine Other Methods to Optimize Tyre Design:

22. 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…

23. Tyre Selection Criteria Based on Performance: Rolling Resistance

24. Rolling Resistance Testing Machine

25. 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

26. Tyre Traction – Subjective & Objective Evaluation

28. 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:

29. 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:

30. Cornering Stiffness Testing

32. Tyre Ride, Comfort & Handling Performance

33. Tyre Ride, Comfort & Handling Performance Breaking Strength Stiffness Test Station

34. 2D - Pattern 3D - Model Marking Hand Carving Tyre testing fitted on vehicle R apid Prototyping

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

39. Functional Parameters: Tread Belt and Breakers Cap Ply/ Prot Ply Carcass Side Wall Bead Chafer Filler Tyre Components:

40. 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.

41. 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.

42. 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

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