1 T i r e s a n d W h e e l s

2 What Wheels Are Made Of  Made  Made of stamped or pressed steel that are either riveted or welded together. or of aluminum or magnesium that are either die-cast or forged.

3 Wheels (cont’d) Wheel offset offset is the vertical distance between the centerline of the rim and the mounting face. Positive – centerline is inboard of mounting face. Negative – centerline is outboard of mounting face. An incorrect tire or wheel size can affect wheel bearing life, and may also affect the antilock brake system.

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5 Wheels RIM RIM FLANGE  FLANGE  Drop center allows for easy tire removal and installation. Where the tire bead makes contact

6 Wheels (cont’d) When installing wheels run lug nuts up evenly in proper sequence to avoid missing one. Torque to manufacturers specification. Over tightening may distort brake rotors Some vehicles may have left-handed wheel studs on the drivers side of the vehicle To measure the bolt circle - 5 lug center of one hole to outside edge of hole farthest away. 4, 6, or 8 lug center of one hole to center of hole directly across.

7Tires Primary purpose is to provide traction. Carry the weight of the vehicle. Transfer braking and driving torque to the road. Help absorb some road shocks. Two Types Two Types Tubeless and Tube type Tubeless and Tube type

8 Types of Tire Construction Bias ply Has a body of fabric plies that run alternately at opposite angles. Has a body of fabric plies that run alternately at opposite angles. Belted bias ply Has two or more belts around the circumference of the tire under the tread. Has two or more belts around the circumference of the tire under the tread. Radial Ply – ( found on modern cars) Has body cords that run at a 90-degree angle to the circumference of the tire. Has body cords that run at a 90-degree angle to the circumference of the tire.

9 Types of Tire Construction

10 Radial Tires Uses various combinations of rayon, nylon, fiberglass and steel in the construction. Better ride. Better fuel economy. Better braking. Better tread life. Better traction “Run-flat” tires have steel reinforced sidewalls that allow the tire to maintain shape with no air pressure. “Run-flat” tires have steel reinforced sidewalls that allow the tire to maintain shape with no air pressure.

11 Radial Tires Designs Directional – designed to rotate in one direction, can only be used on one side of vehicle. Arrow on sidewall indicates direction of travel. Nondirectional – has the same handling qualities in either direction of rotation.

12 DirectionalNondirectional

13 Radial Tires Designs (cont’d) Symmetric – has the same tread pattern on both sides of the tire. Asymmetrical – has a tread design that is different from one side to the other.

14 Symmetrical Asymmetrical

15 Tire Sidewall Markings Max Load Max Inflation Pressure Tread Plies Sidewall Plies Wear Ratings Traction Ratings Temperature Ratings

16 Tire Ratings Profile – aspect ratio also known as Series. Size Load range – how much weight the tire can carry at the recommended tire pressure. Tread wear – ratings from 100 to 600. Traction – ratings AA, A, B, C. Temperature – ratings A, B, C.

17 Tire Aspect Ratio

18 Meaning of a P205/75R15 Tire Designation P = Passenger car tire P = Passenger car tire 205 = Tire width (in millimeters) 75 = Height to width ratio (in %) 75 = Height to width ratio (in %) R = Identifying radial construction R = Identifying radial construction 15 = Rim diameter (in inches) 15 = Rim diameter (in inches)

19 Tire Care Tire Placard – usually found on the drivers door jam. Includes recommended max vehicle load, tire size, and cold tire inflation for that vehicle. Check air pressure frequently Rotate tires – to equalize tire wear Check tread wear – most tires have a built in tread wear indicator which shows when the tire needs replacement (at 2/32).

20 Tire Care Check for uneven tire wear Check for uneven tire wear To correct you may need to: Balance tires Alignment Check air pressure pressure

Tire Rotation 21

22 Tire Care Most tire failures are caused by: Most tire failures are caused by: Improper maintenance OverloadingAge

23 Tire Balancing Static Balance – balancing a wheel at rest using a bubble balancer. Dynamic Balance – balancing a wheel in motion using a spin balancer.

24 Tire Replacement Conditions BulgesBlisters Ply separation Broken or cracked beads Fabric cracks or cuts Wear indicators showing (2/32 inch) Sidewall Punctures Note: always replace valve stem when replacing tires.

25 Tire Repair Plug repair – can be done on the vehicle. Cold patch – tire must be dismounted, buffed down around the puncture, cleaned, glued then patched. Run a stitching tool over patch to help bind it to the tire.. Patch Plug- Best way to repair tire, same procedure as patch better fix

L75 mph120 km/hOff-Road & Light Truck Tires M81 mph130 km/h N87 mph140km/hTemporary Spare Tires P93 mph150 km/h Q99 mph160 km/hStudless & Studdable Winter Tires R106 mph170 km/hH.D. Light Truck Tires S112 mph180 km/hFamily Sedans & Vans T118 mph190 km/hFamily Sedans & Vans U124 mph200 km/h H130 mph210 km/hSport Sedans & Coupes V149 mph240 km/hSport Sedans, Coupes & Sports Cars Beginning in 1991, the speed symbol denoting a fixed maximum speed capability of new tires must be shown only in the speed rating portion of the tire's service description, such as 225/50R16 89S. The most common tire speed rating symbols, maximum speeds and typical applications are shown below:

Load IndexPoundsKilogramsLoad IndexPoundsKilograms

37 The End