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Tire Design, Manufacturing and Performance Considerations
CIWMB Market Development and Sustainability Committee
Sacramento, CASeptember 12, 2007
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RMA Tire Company RepresentativesHere Today:
Bridgestone Americas John Sheerin
Continental Tire North America Don Amos
The Goodyear Tire & Rubber Co. Sim Ford
Michelin North America Mike Wischhusen
Yokohama Tire Dan Guiney
4
Presentation Outline• Tire Performance Overview
– Mike Wischhusen, Michelin North America• Governmental Requirements
– Dan Guiney, Yokohama Tire Corporation• Tires, Tire Tread Wear and Vehicle Fuel
Economy– Sim Ford, The Goodyear Tire and Rubber Co.
• Recycled Content and New Tires– Don Amos, Continental Tire North America
• Conclusions– Tracey Norberg, RMA
Section 1:Tire Performance
OverviewMike Wischhusen
Michelin North America
6
The hidden side of the tire
A round shape made from rubber
Is it that simple ?
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The hidden side of the tire
A tire also contains hidden complexity
Crown structure:
Nylon belt pliesSteel belt plies
Casing ply
Reinforcement
Heel-shaped anchorage to the rim Inner liner
Tread band and tread pattern
Separating rubber
Sidewall
Casing ply turn-up
Bead wire
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At the steering wheel, the only thing linking you
to the road is the tire.
The tire: your only contact with the ground
150 cm2 500
cm2
= 1 HAND
= 3 HANDS
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Obeying the driver's orders:
Grip and road handling:
1
1 carry
2
2 roll
3
3 steer
10
Traction on Wet Surfaces
The tire pushes the water out towards the sides
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1
1
The tire's tread dries the road.2
2
2
2
The ribs in the tread pattern cut through the residual film of water.
3
3
3
3
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Vehicle Handling
A tire under great stress:
- steering - acceleration
- brakingContact patch
Skid angle
Axis of wheel direction
Thrust of ground
Axis of trajectory
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Working in the long term
WEAR = loss of tread depth as the mileage rises
The wear life span depends mainly on the rolling conditions
Number of cases in sample observed
STATISTICAL DISTRIBUTION OF LIFE SPANS
severe normal gentle Very gentle
Rolling conditions
20 000 40 000 60 000 80 000
miles
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Rolling Tire
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Transversal Bending
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Endurance
60 miles per hour means 10 – 15 revolutions per second, or 20 to 30 deformations per second (20 – 30 Hz)
Working in the long term
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Mechanical and acoustic comfort
Obstacle on the road: noise and vibrations
Measurement of noise
when a vehicle passes
Constant improvements in comfort
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Tire with 3 patternsizes
Acoustic comfort
Tread blocks with irregular orientation=noise reduction
Rectilinear impact front: all the tread blocks across the width of the tire enter into contact with the ground at the same time.
Rolling direction
Constant improvements in comfort
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Average ConsumerRolling resistance
Rotational direction
Energy loss due to deformations
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Rubber Compounds
energy loss
LOW HYSTERESIS
MATERIAL
Reduce Rolling
Resistance
energy loss
HIGH HYSTERESIS
MATERIAL
Increase Traction
No energy loss
PERFECTLY ELASTIC
MATERIAL
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Rolling Resistance and Hysteresis
60 mph means 10-15 deformations per second, 10-15 Hz.
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Grip and Hysteresis
The surface deformation
responsible for grip occurs
at frequencies between 103
and 1010 Hz
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10 100000100001000100
Rolling ResistanceRange
Grip Range
RR, Grip and HysteresisH
YS
TE
RE
SIS
FREQUENCY Hz (log scale)
En
erg
y D
issi
pat
ion
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HY
ST
ER
ES
IS
FREQUENCY Hz (log scale)
10 100000100001000100
Rolling ResistanceRange
Grip Range
En
erg
y D
issi
pat
ion
RR, Grip and Hysteresis
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Coefficient of rolling resistance in kg/t
First pneumatic tires
First radial tires
Green X Energy
3Energy
First metallic
tires
First steel
belted tires
30
25
20
15
10
5
01880 1900 1920 1940 1960 1980 2000 2020
Solid tires
Car tires
Truck tires
Train wheels on
track
Metro tires
Tires for Shell Eco
Marathon
Orders of magnitude in 2002 :
- Tires for cars : 8,5 à 13 kg/t
- Tires for trucks : 4,5 à 10 kg/t
- Tires for bicycles : 2,5 à 5 kg/t
Rolling resistance
Consuming less
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The art of balanceCar tires
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US Car/Light Truck Sales
6000000
7000000
8000000
9000000
10000000
11000000
12000000
Year
Car
Light Truck
Source: Automotive News 2007 Global Market Data Book
Section 2: Governmental Requirements
Dan GuineyYokohama Tire Corporation
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U.S. Government Requirements
• Performance Standards– Passenger Tires – Federal Motor Vehicle
Safety Standard (FMVSS) 109 – will be changing to 139 in September 2007
– Commercial Tires – FMVSS 119 – also being revised; proposal expected soon
• Tire Labeling – specifications for information on tire sidewall
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U.S. Government Requirements• Consumer Information Requirements
– Uniform Tire Quality Grading• Traction, Tread Wear, Temperature
– Applies to same tires as AB 844
• Early Warning Reporting – vehicle and component manufacturers required to report production, warranty and property damage claims, injuries and fatalities to NHTSA
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Compliance with US Governmental Requirements
• Compliance with federal requirements demonstrated through self-certification of product
• NHTSA conducts compliance audits of sample of tires each year to assess compliance
• Companies also self-report if compliance or defect issue is discovered with a particular tire
• Companies conduct voluntary consumer satisfaction programs and mandatory recalls if necessary
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Tire Testing / Grading• Uniform Tire Quality Grade – 49 CFR §575.104
– TreadwearComparative rating based on wear rate of the tire when tested under controlled conditions on a specified government test course.
– TractionRated AA, A, B, C. Grades represent the tire’s ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces.
– TemperatureRated A, B, C. Grades represent the tire’s resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel.
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International Governmental Requirements
• Europe• Japan• Saudi Arabia• Other Countries (India, China, Brazil, Australia,
Mexico, Peru, etc.)
34
Customer Requirements
• Tire industry must also meet exacting customer requirements
• Original equipment (auto company) customers typically interested in low rolling resistance, ride, handling, noise, comfort
• Replacement market customers interested in long tread life, traction and price
Section 3: Tires, Tire Tread Wear and
Vehicle Fuel Economy
Sim FordThe Goodyear Tire & Rubber
Company
36
Environmental Considerations in the Design Process
• Tire materials content issues• Manufacturing emissions issues• Toxicity issues• Worker health and safety issues• Tire rolling resistance and vehicle fuel
economy• Tread wear miles and scrap tire generation
37
California Interests• California Energy Commission addressing “tire
efficiency” – tire rolling resistance and vehicle fuel economy– RMA is working closely with CEC on implementation of AB 844
• CIWMB addressing scrap tire issues– RMA is committed to working with CIWMB on these issues
• Tire rolling resistance and tire tread life are interrelated tire performance properties
• Key is to balance interest in improving vehicle economy with interest in longer wearing tires, so as not to create unintended consequences
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Tire Rolling Resistance• Tire rolling resistance is the tire’s contribution
to vehicle fuel economy• The lower the tire rolling resistance, the more
fuel efficient the vehicle will be, all other things being equal
• Tire rolling resistance is affected by:– Tire design and construction– Rubber compounds– Tire inflation pressure– Roadway surface– Vehicle alignment
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Improved compound and construction technologies can minimize performance trade-offs. Expect potential trade-offs in dry traction and wear.
Rolling Resistance
Fuel Economy
Dry
Wet
Snow
Treadwear
Rolling Resistance Trade-Offs
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Rolling Resistance Impact on Fuel Consumption
National Research Council, "Automotive Fuel Economy: How Far Should We Go?", 1992)
Fuel energy is dissipated in many ways, including rolling resistance:
A 10% improvement in rolling resistance gives a 1-2% improvement in fuel economy
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Rolling Resistance Impact on Fuel Consumption
U.S. Department of Energy – “Energy Technology and Fuel Economy” - Typical energy losses in city driving.
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Rolling Resistance Impact on Environment
• Improved rolling resistance performance reduces vehicle fuel usage– 1-2% for every 10% improvement in tire rolling resistance– Poor tire inflation maintenance negates tire design benefits
• Improved rolling resistance decreases tire wear life, so more tires are required for the same miles– More raw materials, more energy to produce and bring to
market– Increased scrap tires
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Longer Tread Wear Tires
• Tires can also be designed to optimize tread wear potential for longer-wearing tires
• Tire tread life is affected by– tire design– tread compound– tire inflation– roadway surfaces– vehicle (size, aerodynamics, loads, alignment) – driver (aggressiveness, maintenance habits)
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• Design trade-offs usually mean reduction in some characteristics to improve others
• Tire wear improvements generally require reduced rolling resistance and traction
Longer Tire Tread Wear Trade-Offs
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05
101520253035404550
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
Avg
Mile
s R
ecei
ved
(00
0's)
Source: Consumer Panel of Vehicle Owning Households * excludes light truck and SUV fitments
Average Tire Mileage 1980 - 2003
46
Longer Life Tires Impact on Environment
• Improving tire tread life – Reduces number of scrap tires– Improves customer satisfaction– Reduces fuel economy
• Reducing tire tread life– Increases materials and energy required to
produce and bring tires to market– Increases number of scrap tires– Poor tire maintenance reduces tread life
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Tire Inflation Pressure – An Environmental Issue!
• Vigilant tire inflation pressure maintenance improves vehicle fuel economy and prolongs tire tread life– Properly inflated tires have lower rolling resistance
than when under inflated– Tires underinflated by 7 psi will achieve 1-2%
reduction in vehicle fuel economy; effects are even greater with lower inflation pressures (TRB, 2006)
– Under inflated tires achieve fewer tread miles due to uneven tread wear caused by the underinflation
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NHTSA Air Pressure Study
• Independent study commissioned by NHTSA in February 2001
• Tire pressure measured on 11,530 vehicles• 6,442 passenger cars• 1,874 SUVs• 1,376 vans• 1,838 pickup trucks
• Tire pressures measured ‘hot’• Survey of drivers
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NHTSA Air Pressure Study
1. 3% of passenger cars and 6% of light truck vehicles have all four tires significantly underinflated
2. 27% of passenger cars and 33% of light trucks have at least one tire significantly underinflated
3. And these tires were measured ‘hot’!
Percent of Tires Underinflated by 8 psi or more0 1 2 3 4
Passenger Cars with P-Metric Tires
73% 14% 7% 3% 3%
Cumulative 27% 13% 6% 3%
Pickups, SUVs, and Vans with P-Metric Tires
67% 13% 10% 4% 6%
Cumulative 33% 20% 10% 6%
Vehicle Type
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Pressure Effects on Tire Wear Performance
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National Tire Care and Maintenance Education Program
RMA Objective:
Educate consumers
about proper tire care and
maintenance.
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Be Tire Smart – Play Your PART
• Pressure -- Check it every month
• Alignment -- vehicle pulling to one side?
• Rotation -- Every 5,000 – 8,000 miles
• Tread -- Penny test
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• Maximize safety
• Improve fuel economy
• Increase tire life
Benefits of Proper Tire Care and Maintenance
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National Tire Safety Week
• Begun in 2002• Serves as tire industry
rallying point to focus attention on tire care
• Provides media opportunities to communicate messages
• Last week in April
55
Transportation Research Board (TRB) Report
• “Tires and Passenger Vehicle Fuel Economy: Informing Consumers, Improving Performance,” April 2006
• 12-member panel studied issues relating to tire rolling resistance, vehicle fuel economy, tread wear, tire inflation pressure and other related issues
• Panel concluded that consumers should be provided with information about a tire’s contribution to vehicle fuel economy at point of sale and that vigilant tire inflation maintenance is important to achieve optimal fuel economy
• RMA working to ensure implementation of TRB findings in Congress
Section 4: Recycled Content in New Tires
Don AmosContinental Tire North America
57
New Tire Manufacturing• Tires contain about 20 components, each
with unique rubber compounds and chemicals
• Tire is “built” and cured, or “vulcanized” with heat and pressure– Tire compounds bond to one another
chemically and physically– Finished product is chemically distinct from
uncured tire components and chemicals – not a sum of its parts
58
Potential Methods of Using Scrap Tires in new Tire Manufacturing
• Devulcanization– Breaking chemical bonds in cured tire material to create
an “uncured” rubber material– Not technically or economically viable
• Pyrolysis– Creating “raw materials” for tire manufacturing (pyrolytic
char substitute for carbon black, oils)– Nor technically or economically viable– Inconsistent product without applications
• Ground rubber– Focus of current recycled content use
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• Ground rubber is the benchmark product
– 30 mesh is threshold for tread
– 80 mesh is threshold for carcass components
– 140 mesh is required some applications
– 200 mesh foreseen for high content
• Pyrolytic char (limited)
Current Methods of Using Recycled Content
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Ground Rubber in New Tires• Recycled content is affected by:
– Ground rubber particle size– Ground rubber content (natural rubber, carbon
black, impurities)– Tire service requirements
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Ground Rubber in New Tires
• Used primarily as a low-cost filler material• Curing materials and anti-degradent content impact
mixing and curing• Reduced size improves performance but increases
cost– typical crumb rubber is 40 mesh
• Increased amounts of recycled material decreases properties and decreases life
• More demanding tire applications (i.e., more heat buildup) can use less recycle content
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Control (0 Crumb) 20 phr* Crumb 30 phr Crumb 40 phr Crumb
Tensile** 100 85 80 75
300% Mod 100 91 82 77
100C Rebound 100 94 93 91
Mooney Scorch 100 93 81 79
Cure Amount 100 92 79 78
Abrasion 100 90 83 68
Heat Build-up 100 89 86 78
Viscosity 100 73 73 56
* Phr is parts by weight per hundred parts of rubber in compound** Lower figures indicate worse performance
Source: Gooodyear
Tread Compound Property Impacts from Ground Rubber Use
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Challenges with Processing Tires for Ground Rubber Use in New Tires
• Tire structure is composed of various rubber compounds, fabric reinforcement, and steel reinforcement
• The structure is designed and manufactured to be resistant to break-down
• Materials must be mechanically separated to be usable
• Ground rubber plant is capital intense with a low margin product
• Feed stock is inconsistent = product is inconsistent
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• P215/60R16 Continental Touring Contact AS– 15 major components– 14 rubber major separate rubber compounds
• 2003 Experimentation• Regular Production: 4.60% 80m-WTGR (10%
in Tread Cap)• Experimental Production: 13.6% 80m & 140m
-WTGR (20% in Tread Cap)+ Pyro black (2.4% to 25% in various components)
Continental Recycled Content Study
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Whole Tire Recycle Impacts
70
80
90
100
RR
GripWear
66
• Study showed negative tire performance implications including – lower tread wear life– lower wet traction– longer wet stopping distance– lower snow traction– higher rolling resistance
• Continental has discontinued this research project due to the unacceptability of the negative performance implications and the unavailability of acceptable source material
Continental Recycled Content Study
67
Recycled Content Impact on Environment
• Increased recycle content in tires– Increases amount of crumb rubber used– Reduces tire durability, performance and tire
life– Tire life decrease approximates recycled
content on percentage basis (Continental study)
Conclusions
Tracey NorbergRubber Manufacturers
Association
69
Conclusions
• Tire manufacturers around the world recognize the need to balance tire safety, customer satisfaction, and environmental concerns
• Tire manufacturers have dramatically improved tire performance, rolling resistance, and tire wear through extensive research and development
• Tire manufacturers are dedicated to ensure safety and improve performance and environmental aspects of tires
70
Thank you!• Questions?
• Comments?
• Contact:Tracey Norberg
Rubber Manufacturers Association
202-682-4839
