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? Today we are going to be talking about the basic of tire construction and a few basic about the theory of the tire. we will be looking at what a tire is made of because we know that it can just be rubber because it is black. So we will actually show you what percent of a tire actually is rubber and is it really black because it is made of rubber.

Actual components that go into a tire. Raw Rubber Steel Nylon Polyester Rayon Carbon Black Synthetic Rubber Fiberglass Aramid Brass Most people think tires are made mostly of rubber. This is far from the truth at all . A tire consist of many different things such as steel. nylon, polyester, rayon, carbon black, synthetic rubber(which is man made rubber), fiberglass which is light weight but add strength, aramid, brass. All these things help add strength, heat distribution, lower the actually weight of the tire, also help protect it from natural weathering (sun, wind, rain, snow).

What percent of a tire is rubber? By weight, give or take 30% By volume, quite a bite more. Yes it is true by volume it may seem that all a tire is made of is rubber. when you actually look at the comparison of weight and components you can see that the actually weight of the tire is only 30% can be blamed on rubber, the rest lies on many of the other components. When you actually look at it you can see why they use so much rubber. The weight factor is actually quite unbelievable when you look at it.

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? It was invented in 1888, by John Dunlop. This would be the end of the solid tire. John was a Scotsman who experimented with covering a rubber tube with canvas to improve the ride comfort of his sons tricycle. After weeks of work the first pneumatic tire came up to its first competitive challenge. On February 28 1888 When rolled across a courtyard, solid tires choked halfway through, but Dunlop’s “MUMMY” tire didn't stop until it crashed into a door.

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. Competitive absorbers work by capturing and absorbing harmful UV light wane Energy. All tire manufacturers use the same competitive absorber, carbon black. This is why tires are black and why tires are not available in designer colors. All UV stabilizers are sacrificial, meaning the are gradually “used up” to where they can no longer protect against UV damage. As carbon black loses the ability to do its job, it turns gray. This is why rubber grays as it ages. OTHER DEGRADENTS Silicone oils can remove the protective waxes and increase the rate of degradation. Common automotive “protectants” and “tire dressings” are typically devoid of UV stabilizers of any type and contain Petrochemicals and/or silicone oils which dissolve away the protective waxes and can actually aggress the sidewall. In the event of warranty sidewall failure, one of the first things tire manufacturers like for is evidence of the use of these types of products. In turn this will void warranty.

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. Has plies running at an angle from bead to bead. The cord angle is also reversed from ply to ply. The tread is bonded directly to the top ply. A bias ply tire is one of the oldest designs and it does NOT use belts. the position of the cords in a bias ply tire allows the body of the tire to flex easily. This tends to improve cushioning action. A bias ply tire provides a very smooth ride on rough roads. One disadvantage is that The weakness of the plies and tread reduce traction at high speeds and increase rolling resistance.

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. Is a bias tire with belts added to increase tread stiffness. The plies and belts normally run at different angles. The belts do NOT run around to the sidewalls but only lie under the tread area. Usually, two stabilizer belts and two or more plies are used to increase tire performance. A belted bias tire provides a smooth ride, good traction, and offers some improvement in tolling resistance over a bias ply tire.

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. Has plies running straight across from bead to bead with stabilizer belts directly beneath the tread. A radial tire has a very flexible sidewall, but a stiff tread. The belts can be made of steel, Flexten, fiberglass, or other materials. Radial tires have a very stable footprint (shape and amount of tread touching road surface). This improves safety, cornering, braking, and wear. One possible disadvantage of a radial tire is that it may produce a harder ride at low speeds. The stiff tread area doesn't give or flex as much on rough roads.

Tire Cutaway

Cooper Tire Cutaway

Tire Sidewall

Tire Sidewall

Tire Size

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

Aspect Ratio Percentage 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.

SERVICE DESCRIPTION On some performance 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, the LOAD INDEX and the SPEED RATING. You'll notice the Speed Rating “S” has been moved from the old Metric size system of: 185/70SR14 to P185/70R14 92S The SPEED RATING is a letter which designates the rating achieved on indoor wheel testing.

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 Index

Speed Rating Rating Maximum Speed Q 99 mph S 112 mph T 118 mph U 124 mph H 130 mph V 149 mph W 168 mph Y 186 mph Z Above 149 mph from goodyear

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 they have a speed rating does not mean the car is safe to drive at those speeds

TIRE GRADING TREAD WEAR, assigned a number, 150 will give you 50% more wear then one ranked 100 TRACTION - A, B, C (A Highest rating) TEMPERATURE - A, B, C,

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°?

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

Effects of low tire pressure Overinflation

Effects of low tire pressure Underinflation

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 accross tread cone shaped

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

Tire Defects

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

Static balance C 77 Equals wheel tramp

Dynamic balance C- 78 equals wobble

Dynamic balance C- 78 equals wobble

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The End for this tire