Tire Tech 101Tire Tech 101Tire Tech 101Tire 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?

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.

What percent of a tire is What percent of a tire is rubber?rubber?

By weight, give or take 30%

By volume, quite a bite more.

Tire compontents

Rubber

Steel Nylon

RayonCarbon Black

Synthetic Rubber

0

10

20

30

What Is Pneumatic Tire?What Is Pneumatic Tire?

Filled by air, especially compressed air: a pneumatic tire (dictionary definition).

All tires manufactured today are considered Pneumatic tires.

Who Invented The First Tire?Who Invented The First Tire?

It was invented in 1888, by John Dunlop.

This would be the end of the solid tire.

Why are Tires Black?Why are Tires Black?Why are Tires Black?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.

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.

Bias Ply TireBias Ply TireBias Ply TireBias 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.

Belted Bias TireBelted 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.

Radial Ply TireRadial 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

Tire CutawayTire Cutaway

Tire CutawayTire Cutaway

Cooper Tire CutawayCooper Tire Cutaway

Tire CutawayTire Cutaway

Tire SidewallTire Sidewall

Tire SidewallTire Sidewall

Tire SidewallTire Sidewall

Tire SizeTire Size

LT = Light Truck

Tire SizeTire 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

Aspect RatioAspect RatioPercentage of tires height in relation to it’s 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.

Aspect RatioAspect 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.

SERVICE DESCRIPTIONSERVICE DESCRIPTION

On most tires, you will notice some additional numbers and letters located at the end of the tire size.

For Example:P185/70R14 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.

Load IndexLoad 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

Load IndexLoad Index

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

Load IndexLoad Index

Speed Rating Speed Rating

from Michelin Tyres 2003

Speed RatingSpeed Rating

ThanksToTireGuides.Com

Effects of speed on a tireEffects 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.

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

TRACTION:Braking capabilities – AA, A, B, C

(AA Highest rating)Traction GradesAsphalt g Force Concrete g Force

AA Above .54 .41

A Above .47 .35

B Above .38 .26

C Less than .38 .26

TIRE GRADING

TEMPERATURE: Ability to withstand extreme heat

- A, B, C

Tire pressureTire 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°?

Tire PressureTire Pressure The EPA says your mileage drops 1% for

every 2 pounds under the recommended tire pressure.

                  

Tire pressureTire pressure Use the tire pressure recommended in your vehicle's

owner's manual or tire information placard

Tire PlacardTire Placard

Driver’s door pillar Glove box door or Center Consol lid Trunk lid or Gas door

Tire pressureTire 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

Tread PatternsTread Patterns Passenger Touring Performance Snow Rain All Season                                                                            

Grand Touring

Performance

Passenger

Competition

High Performance

                                                   

           

                                            

           

Net to Gross Ratio – The amount of rubber hitting the road.

35 psi sitting still in water

35 psi at 60 mph

30 psi at 60 mph

25 psi at 60 mph

Effects of Tire pressure and Speed on wet traction

Nitrogen in tiresNitrogen 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.

Effects of tire pressure Effects of tire pressure Over inflationOver inflation

Wide tires that are under inflated can also wear in the center

Effects of tire pressure Effects of tire pressure Under inflationUnder inflation

Tire DefectsTire 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

Tire WearTire Wear

CuppingCupping

Tire DefectsTire Defects

BulgeBulge

Tire DefectsTire Defects

Chunk OutsChunk Outs

Tire DefectsTire Defects

CracksCracks

Tire Defects, Foreign ObjectsTire Defects, Foreign Objects

Tire WearTire Wear Side Wear & FeatheringSide Wear & Feathering

Tire PullTire Pull Defective/damaged tires Bent wheel (rim) Excessive shoulder wear Excessive feathering

Tire DefectsTire Defects

Tire WearTire Wear

Tire WearTire Wear

Tire WearTire Wear

Tire RotationTire Rotation Tires should be rotated between 5,000 and 7,500

miles see charts on how to rotate

Thanks to Michelin for the picture

Tire RotationTire Rotation

Effects of Mismatched TiresEffects 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

Tire ReplacementTire Replacement One problem with replacing just one tire on FWD,

AWD or 4X4’s 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 cause’s 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

WheelsWheels

steel \ cast Off set Bump steer Scrub Radius

– note pages C 311- 313

How to measure a rimHow 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 takea good guess where it is on the outside. This one is 14 inch’s.

How to measure a rimHow 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 rimThat math class is important.

Wheel BalanceWheel 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

Static balanceStatic balance

C 77 Equals wheel tramp or hop weight not even around

the tire must add weight to other side to equal it out.

Dynamic balanceDynamic balance

C- 78

equals wobble side to side weights not equal

Wheel BalanceWheel 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.

Wheel BalanceWheel Balance

Hub centric or cone adapter

lug centric

Air Pressure MonitorsAir 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!

Tire Pressure QuizTire Pressure Quiz

(Roll your mouse across the pictures to confirm you were right)

Can you easily identify which tire is 30% under inflated with your eyes? Here is what they would look like in the morning as you

walked to your car in the garage.

                                                                                                                                                                 

20 psi cold 29 psi cold

Tire Pressure MonitoringTire 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

Direct TP Warning SystemDirect TP Warning System Computer controlled (BCM) w/ radio

transmitters in wheels (pressure sensors) Transmits actual TP of each tire Displays on IPC Diagnostic capabilities

Indirect TP Warning SystemIndirect 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

Tire Pressure MonitoringTire 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.

Run Flat TiresRun Flat Tires

Run Flat TiresRun 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

Run Flat TiresRun Flat Tires Michelin unveiled the “Tweel” at the 2005 North

American International Auto Show Increased mobility, lateral stability, and gas mileage

For more information go toFor more information go to A big thanks goes to these companies for use

of pictures and information

                                                     

Good heart - Wilcox

http://tireguides.com/default.asp Tire Guides Inc

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