Commercial Tire Retreading


                Robert C. McElroy, Ph.D.

                 www.ForensicAccident.Com


Canadia...
Tire Definition




                                                   Bubba
Academic                                     ...
Retread Training Program

         Dr. McElroy Attended ITRA Training
         Institute 40 Hour Commercial Tire
         ...
Retreading Is:


                                                       •
                                                ...
What is a Worn Casing


                                             •is a properly
                                      ...
Vulcanizing or Curing



                                             •
                                             Proce...
Vulcanizing Involves



                                             •
                                             Time
 ...
Tire Classification
                                             •
                                             Passenger
...
Tire Retreading Involves
                                             •
                                             Inspe...
Mold Cure Retreading




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 10
Pre Cure Retreading




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 11
Today’Professional Retreader
      s
     Must Know & Understand
                                        • construction
  ...
Maintenance &
                                              Wheel Position




Canadian Association of Technical Accident ...
Tread Compounds
                                           Should Have:


• heat generation
Low
• traction
Good
• tear res...
Rolling Resistance
                                         Is Affected By:
                                            • ...
Road Factors



                                            •
                                            Surface Characte...
Vehicle Factors
                                            •
                                            Speed
          ...
Heat History


          • quantity of heat accumulated
          The
          over a period of time.




Canadian Associ...
Tire Heat Exposure


                                            •
                                            Original ma...
Typical Radial Truck Tire
                   Operating on the Road

          200o F 93o C




Canadian Association of Tec...
Typical Radial Truck Tire
                        Original Tread Life

200,000 to 250,000 Miles
320,000 to 400,000 KM




...
Loads




                                                           Heat buildup area

Canadian Association of Technical ...
Tire Inflation Pressure
                                            • / under inflation.
                                 ...
Low Air Pressure

                                            •
                                            Increases runn...
Effects On Tread Wear
                                            • inflation by 10%
                                     ...
To Select Tires for Retreading

                                            •
                                            ...
Inspect Tires
                                            •
                                            Physical inspectio...
Electronic Inspection




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 28
Physical Inspection




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 29
Non Retreadable Tires
•
Damaged cord                              • blister
                                          Line...
New Tire DOT Codes

 DOT MC 31 2XOW 086
• - Meets or exceeds DOT safety standards
DOT
• - Manufacturer & plant code
MC
•
2...
Retread Plant DOT Codes
R - ARA CI XXX 086 FI
• identifies as retread
R-
• - shop identification code
ARA
• - identifies m...
Buffing Template Shape




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 33
Buffed Radius Check Gauge




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 34
Buffing Machine




         Buffing Head


          Template
Canadian Association of Technical Accident Investigators an...
Apply Cement To:

•
Protect buffed surface & exposed cords
from oxidation.
•
Improves adhesion by providing for more
“inti...
Cement Tire Casing




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 37
Cement = Rubber Solids
                         Dissolved in Solvents

•
Allow 15 minutes to dry after application.
•
Inst...
Cement Application




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 39
Gum Cushion Application



                                            •
                                            Apply...
Gum Cushion to Tire Contact




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 41
Trim Gum Cushion




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 42
Gum Cushion Base Material


                                            •
                                            Pres...
Precure Tread Installation
  •
  Texturize tread end & cement.
  • tread straight holding tightly.
  Feed
  • cut point ev...
Precure Tread
                           Installation & Cutting




Canadian Association of Technical Accident Investigato...
Gum Cushion Base Material
               Connects Tread Ends




Canadian Association of Technical Accident Investigators ...
Poly Installation




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 47
DOT Identification Code
                                 Installation




Canadian Association of Technical Accident Inves...
Select Tire Envelope




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 49
Envelope on Expander




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 50
Envelope Expanded




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 51
Tire Insertion




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 52
Envelope Adjustment




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 53
Rim & Flange Installation




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 54
Prepared Tires For Chamber




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 55
Curing in
                          Autoclave or Chamber




Canadian Association of Technical Accident Investigators and ...
Track Installation




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 57
Envelope & Rim
                            Pneumatic Connections


                                                       ...
Seal & Lock Chamber




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 59
Set Time & Temperature




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 60
Post Vulcanization




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 61
Final Inspection




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 62
References




Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 63
Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 64
Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 65
Dr. McElroy Examining Retreaded Tire                              The End




 Canadian Association of Technical Accident ...
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C - Retread Procedures for Commercial Tires

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Presentation sildes taken to document Commercial Tire Retreading class at Internation Tire and Rubber Association. In 2002 ITRA merged with TANA to form the current Tire Industry Association (TIA)

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C - Retread Procedures for Commercial Tires

  1. 1. Commercial Tire Retreading Robert C. McElroy, Ph.D. www.ForensicAccident.Com Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 1
  2. 2. Tire Definition Bubba Academic big & dirty flexible pressure vessel flat-on-bottom Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 2
  3. 3. Retread Training Program Dr. McElroy Attended ITRA Training Institute 40 Hour Commercial Tire Retreading Class Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 3
  4. 4. Retreading Is: • Bonding a new tread to a worn tire casing Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 4
  5. 5. What is a Worn Casing •is a properly It maintained tire that has worn out its useful tread life and been removed from service for retreading. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 5
  6. 6. Vulcanizing or Curing • Process of chaining macromolecules together. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 6
  7. 7. Vulcanizing Involves • Time • Temperature • Pressure Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 7
  8. 8. Tire Classification • Passenger • Truck Light • Medium Truck • Heavy Truck • Off-Road • Aircraft • Agricultural • Industrial / Mining • Racing Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 8
  9. 9. Tire Retreading Involves • Inspection • Repairing • Buffing / Skiving • Cementing / Filling • Tread Application • Wicking / Enveloping • Vulcanization • Inspection Final Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 9
  10. 10. Mold Cure Retreading Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 10
  11. 11. Pre Cure Retreading Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 11
  12. 12. Today’Professional Retreader s Must Know & Understand • construction Tire • sizes & what they Tire mean • usage & application Tire • maintenance Tire • Tread design & functions • Retread processing technology Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 12
  13. 13. Maintenance & Wheel Position Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 13
  14. 14. Tread Compounds Should Have: • heat generation Low • traction Good • tear resistance High • rolling resistance Low Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 14
  15. 15. Rolling Resistance Is Affected By: • load Tire • Inflation • Tread compound • construction Tire • Tread depth • Tread design Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 15
  16. 16. Road Factors • Surface Characteristics • Water depth • Temperature Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 16
  17. 17. Vehicle Factors • Speed • Mode of operation • Suspension • Braking system • Types of load – liquid – CG high Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 17
  18. 18. Heat History • quantity of heat accumulated The over a period of time. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 18
  19. 19. Tire Heat Exposure • Original manufacturing temperatures. • Original tread life operating temperatures. • Retread process temperatures. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 19
  20. 20. Typical Radial Truck Tire Operating on the Road 200o F 93o C Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 20
  21. 21. Typical Radial Truck Tire Original Tread Life 200,000 to 250,000 Miles 320,000 to 400,000 KM Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 21
  22. 22. Loads Heat buildup area Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 22
  23. 23. Tire Inflation Pressure • / under inflation. Over • Buffed too round / too flat. • retread / narrow Wide retread. • / narrow Wide processing rims or narrow road rims. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 23
  24. 24. Low Air Pressure • Increases running temperature. • Reduces fuel economy. •20% reduction in A inflation pressure causes a 16% reduction in tread life. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 24
  25. 25. Effects On Tread Wear • inflation by 10% Over reduces tread life 5- 8%. • inflation by 20% Over reduces tread life 16%. • Matching duals • Torque, braking, stopping & cornering. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 25
  26. 26. To Select Tires for Retreading • Manufacturing defects • Non-repairable damage • Excessive age • tire be retreaded Can again? Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 26
  27. 27. Inspect Tires • Physical inspection – hands – grazing light • Electronic inspection • Ultrasonic inspection • destructive Non testing •ray X Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 27
  28. 28. Electronic Inspection Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 28
  29. 29. Physical Inspection Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 29
  30. 30. Non Retreadable Tires • Damaged cord • blister Liner • Improper repair • heat stress Liner • Chipped bead • Mount/demount damage • Broken body plies • Improper repair • Zipper rupture • splice separation Liner • Sidewall separation • damage Liner • stress Flex • Regroving damage • turnup separation Ply • deterioration Age Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 30
  31. 31. New Tire DOT Codes DOT MC 31 2XOW 086 • - Meets or exceeds DOT safety standards DOT • - Manufacturer & plant code MC • 2XOW - optional identification symbols • - date of manufacture (08 week, 1996) 086 Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 31
  32. 32. Retread Plant DOT Codes R - ARA CI XXX 086 FI • identifies as retread R- • - shop identification code ARA • - identifies matrix that the tire was C1 cured in or is a tire size code • - optional grouping XXX • - date code 086 • - steer axle option F1 Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 32
  33. 33. Buffing Template Shape Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 33
  34. 34. Buffed Radius Check Gauge Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 34
  35. 35. Buffing Machine Buffing Head Template Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 35
  36. 36. Apply Cement To: • Protect buffed surface & exposed cords from oxidation. • Improves adhesion by providing for more “intimate contact” to buffed casing. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 36
  37. 37. Cement Tire Casing Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 37
  38. 38. Cement = Rubber Solids Dissolved in Solvents • Allow 15 minutes to dry after application. • Install tread within 12 hours. • Chemical • vulcanizing Black • Concentrated or brush • Spray • Extruder or hot tack Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 38
  39. 39. Cement Application Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 39
  40. 40. Gum Cushion Application • Apply gum cushion base material, • a prepared casing. To Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 40
  41. 41. Gum Cushion to Tire Contact Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 41
  42. 42. Trim Gum Cushion Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 42
  43. 43. Gum Cushion Base Material • Pressure roller ensures attachment of gum base material to prepared casing. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 43
  44. 44. Precure Tread Installation • Texturize tread end & cement. • tread straight holding tightly. Feed • cut point even or slightly longer. Mark • straight & match tread design if possible. Cut • cushion between tread ends. Place • splice with least amount of hump. Butt • rubber toward splice & from center out. Work • Install DOT identification code. • Apply poly. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 44
  45. 45. Precure Tread Installation & Cutting Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 45
  46. 46. Gum Cushion Base Material Connects Tread Ends Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 46
  47. 47. Poly Installation Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 47
  48. 48. DOT Identification Code Installation Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 48
  49. 49. Select Tire Envelope Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 49
  50. 50. Envelope on Expander Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 50
  51. 51. Envelope Expanded Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 51
  52. 52. Tire Insertion Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 52
  53. 53. Envelope Adjustment Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 53
  54. 54. Rim & Flange Installation Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 54
  55. 55. Prepared Tires For Chamber Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 55
  56. 56. Curing in Autoclave or Chamber Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 56
  57. 57. Track Installation Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 57
  58. 58. Envelope & Rim Pneumatic Connections Envelope Rim Connection Connection Vacuum Pressure Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 58
  59. 59. Seal & Lock Chamber Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 59
  60. 60. Set Time & Temperature Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 60
  61. 61. Post Vulcanization Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 61
  62. 62. Final Inspection Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 62
  63. 63. References Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 63
  64. 64. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 64
  65. 65. Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 65
  66. 66. Dr. McElroy Examining Retreaded Tire The End Canadian Association of Technical Accident Investigators and Reconstructionists - 1999 66

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