Tire Tech 101

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Tire Tech 101

• What is a tire made of.
• What percent of a tire is rubber?
• What is a pneumatic tire?
• What is the difference between radial bias ply
  tires ?
• Why are tires black?

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Actual components that go into a tire.

• Raw Rubber
• Steel
• Nylon
• Polyester
• Rayon

• Carbon Black
• Synthetic Rubber
• Fiberglass
• Aramid
• Brass

Aramid A synthetic fabric used in some tires
that is (pound-for-pound) stronger than steel.
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What percent of a tire is rubber?

• By weight, give or take 30
• By volume, quite a bite more.

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What Is Pneumatic Tire?

• Filled by air, especially compressed air a
  pneumatic tire (dictionary definition).
• All tires manufactured today are considered
  Pneumatic tires.

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Who Invented The First Tire?

• It was invented in 1888, by John Dunlop.
• This would be the end of the solid tire.

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Why are Tires Black?

• To protect the rubber from the harmful UV rays.
• A common type of UV stabilizer called a
  competitive absorber is added to capture and
  absorb these harmful UV light wave energy.

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Bias Ply Tire

• A bias ply tire has plies running at an angle
  from bead to bead.
• The cord angle is also reversed from ply to ply.
• Tread is bonded directly to the top ply.

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Belted Bias Tire

• Is a bias tire with belts added to increase tread
  stiffness.
• These belts are also ran at a different angle.
• These belts only lie on the tread area and not on
  the side walls, like cords.

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Radial Ply Tire

• Has plies running straight across from bead to
  bead with stabilizer belts lying directly beneath
  the tread.
• This results in the radial having flexible side
  wall, but a stiff tread.
• Michelin developed it in 1955! 50 years ago!
• Sears imported them in the 1970s

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Tire Cutaway
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Tire Cutaway
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Cooper Tire Cutaway
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Tire Cutaway
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Tire Sidewall
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Tire Sidewall
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Tire Sidewall
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Tire Size
LT Light Truck
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Tire Size

• If you switch tire size on a car you can mess up
  the speedometer to figure out how close you are
  do the math to figure out the diameter.
• For a 205/75R15 tire it would look like this
• 205 X .75 x 2 25.4 15 27.106
• Tire size X Aspect ratio X 2 25.4 Rim size
• 100

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Aspect Ratio
Percentage of tires height in relation to its
width A 60 series tire height will be 60 of the
width. The aspect ratio can be a 40,50,
60,65,70,75,78 These are some of the most
common ones.
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Aspect Ratio
So if we have a P205/60R15 tire. The width is
205 millimeters and the height is 60 of the
width. That means 205 x .6 123 millimeters.
That tire should be 123 millimeters tall. You
can raise or lower your car by changing the
height of the side wall.
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SERVICE DESCRIPTION

• On most tires, you will notice some additional
  numbers and letters located at the end of the
  tire size.
• For ExampleP185/70R14 92S
• In this example the 92S is called the SERVICE
  DESCRIPTION.
• The Service Description consists of two parts,
  LOAD INDEX (the numbers) and SPEED RATING(the
  letter).
• The SPEED RATING is a letter which designates the
  rating achieved on indoor wheel testing.

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Load Index

• The LOAD INDEX is a number ranging from 0 to 279
  and covers load capacities from the smallest
  motorcycle tires to those for the largest earth
  mover tires. In passenger car tires, the load
  index typically ranges from 75 to 100.
• As in aspect ratio where the operative word was
  ratio, in load index the operative word here is
  index. An index is a point of reference or a
  chart to refer to find information. All tire
  guides used by retail tire stores have them and
  they have load index charts in them. By referring
  to the load index chart in the Tire Guide you can
  determine the maximum load carrying capacity of a
  tire size from using the load index number at the
  end of the P-Metric size.
• For Example
• Load Index Max Load (lbs.)
• 91 1356
• 92 1389
• 93 1433

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Load Index
For a complete listing of load index ratings go
to this web site
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Load Index

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Speed Rating
from Michelin Tyres 2003
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Speed Rating
Thanks To Tire Guides. Com
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Effects of speed on a tire
Tires are tested under Laboratory conditions they
are not worn out, are properly inflated, not over
loaded, damaged or altered. Just because the
tire is rated at these speeds does not mean the
car is safe or legal to drive at those speeds.
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TIRE GRADING

• Uniform Tire Quality Grading System Code UTQGS
• TREAD WEAR Tire life expectations 100 is base
  line, 150 will give you 50 more wear then one
  ranked 100 (100 30,000 miles
• TRACTIONBraking capabilities AA, A, B, C
• (AA Highest rating)

Traction Grades Asphalt g Force Concrete g
Force AA Above .54 .41 A Above
.47 .35 B Above .38 .26 C Less than .38 .26
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TIRE GRADING

• TEMPERATURE Ability to withstand extreme heat
• - A, B, C

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Tire pressure

• Tire pressure should be check monthly
• Tire pressure should be checked cold
• For every 10 Fahrenheit change in air
  temperature, your tire's inflation pressure will
  change by about 1 psi
• The air pressure in the tire supports the car,
  make sure that it is the right amount.
• If you check the air pressure inside the shop at
  a temperature of 70 will the tires be the right
  pressure when it goes outside at 0?

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Tire Pressure

• The EPA says your mileage drops 1 for every 2
  pounds under the recommended tire pressure.

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Tire pressure

• Use the tire pressure recommended in your
  vehicle's owner's manual or tire information
  placard

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Tire Placard

• Drivers door pillar
• Glove box door or Center Consol lid
• Trunk lid or Gas door

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Tire pressure

• This is the Maximum pressure for the tire not the
  normal pressure, use only if car is fully loaded.

Thanks to Michelin for the picture
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Tread Patterns
Competition

• Passenger
• Touring
• Performance
• Snow
• Rain
• All Season

Performance
Grand Touring
High Performance
Passenger
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Net to Gross Ratio The amount of rubber hitting
the road.
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35 psi sitting still in water
Effects of Tire pressure and Speed on wet traction
35 psi at 60 mph
30 psi at 60 mph
25 psi at 60 mph
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Nitrogen in tires

• Nitrogen is a dry inert gas. That means moisture
  free.
• Nitrogen leaks out of the sidewall three times
  slower then oxygen.
• Oxygen oxidizes the rubber in the sidewall. Plus
  the moisture in the air will rust the steel rims.

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Effects of tire pressure Over inflation
Wide tires that are under inflated can also wear
in the center
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Effects of tire pressure Under inflation
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Tire Defects

• Separations
• Bulges
• sidewall separations
• tread tearing, chunking
• shoulder cracking
• Sidewall cracking

• Weather cracking
• Breaks in sidewall/tread
• Excessive radial runout
• diameter
• Excessive lateral runout
• width
• Conicity
• not level across tread
• cone shaped

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Tire Wear
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Cupping
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Tire Defects
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Bulge
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Tire Defects
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Chunk Outs
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Tire Defects
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Cracks
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Tire Defects, Foreign Objects
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Tire Wear Side Wear Feathering
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Tire Pull

• Defective/damaged tires
• Bent wheel (rim)
• Excessive shoulder wear
• Excessive feathering

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Tire Defects
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Tire Wear
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Tire Wear
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Tire Wear
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Tire Rotation

• Tires should be rotated between 5,000 and 7,500
  miles see charts on how to rotate

Thanks to Michelin for the picture
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Tire Rotation
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Effects of Mismatched Tires

• Different Manufactures
• Different sizes
• New and/or used tires
• Effects on speedometer
• Effects on ABS/Traction Control Systems
• Effects on vehicle handling

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Tire Replacement

• One problem with replacing just one tire on FWD,
  AWD or 4X4s is that you have a different size
  tire when you measure the circumference this
  creates a problems with the transaxles and drive
  trains. It also causes problems with traction
  control and ABS stopping. Tires need to be
  rotated at least every 7500 miles and if one tire
  is damaged on one of these cars all 4, count them
  FOUR tires need to be changed. Tread depth
  should be maintained within 4/32 of each tire.

For more info go to
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Wheels

• steel \ cast
• Off set
• Bump steer
• Scrub Radius
• note pages C 311- 313

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How to measure a rim
You need to measure from bead seat to bead seat.
But you cannot measure from the inside with a
tape measure take a good guess where it is on the
outside. This one is 14 inchs.
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How to measure a rim
To find the diameter you measure the
circumference (C) and divide it by Pi (3.14)
( C Pi Diameter ) 44 3.14 14.0127
So it is really a 14 inch rim That math class is
important.
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Wheel Balance

• Improper balance causes the tire to vibrate
  several types of balancers, Bubble balancers, on
  car balancers and off car balancers shown. Some
  are hand spun and some are powered

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Static balance

• C 77
• Equals wheel tramp or hop
• weight not even around the tire must add weight
  to other side to equal it out.

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Dynamic balance

• C- 78
• equals wobble side to side weights not
  equal

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Wheel Balance

• Make sure when you balance a tire to use the
  right adapter some wheels are Hub centric or lug
  centric that means does it center on the Hub or
  the lugs most cars from the factory are Hub
  centric but some after marker wheels are lug
  centric
• If you think that your balancer is not working
  right or the wheel is off check the balance
  rotate it 180 degrees and rebalance it. It
  should have the same readings.

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Wheel Balance

• Hub centric or cone adapter
• lug centric

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Air Pressure Monitors

• May have a sensor inside tire
• May have a sensor in the tire valve stem!
• Sensors may have to be recalibrated after a tire
  rotation!

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Tire Pressure Quiz
(Roll your mouse across the pictures to confirm
you were right)
29 psi cold
20 psi cold
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Tire Pressure Monitoring

• Warns of significant lose of tire pressure
• First used on 1994 Corvette
• All cars LD Trucks must have TP system by 2008
• Two types Direct and Indirect

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Direct TP Warning System

• Computer controlled (BCM) w/ radio transmitters
  in wheels (pressure sensors)
• Transmits actual TP of each tire
• Displays on IPC
• Diagnostic capabilities

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Indirect TP Warning System

• ABS based system, using existing ABS hardware, w/
  software modifications
• Changes in TP affect tire circumference,
  affecting tire speed
• Sensors monitor each wheels speed, compares to
  one another
• Approx. 7 psi difference to trigger warning

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Tire Pressure Monitoring

• Before you do any work on these cars, make sure
  that the warning lights are off before you work
  on the car. If you mount or dismount the tire
  and it was not working right before, you could be
  blamed for causing a problem.
• You need to do this with all cars and with all
  warning lights such as, check engine ABS etc.

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Run Flat Tires
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Run Flat Tires

• Temp. supports weight of vehicle with no air
  pressure
• Internal support, thicker side walls, stronger
  beads.
• Can maintain Mobility for 50 miles up to 55 mph

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Run Flat Tires

• Michelin unveiled the Tweel at the 2005 North
  American International Auto Show
• Increased mobility, lateral stability, and gas
  mileage

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For more information go to

• A big thanks goes to these companies for use of
  pictures and information

http//tireguides.com/default.asp Tire
Guides Inc
Good heart - Wilcox
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The End ??????