Wheels And Tires Keyterm

Front 1

The ratio of sidewall height to section width of a tire

Back 1

Aspect Ratio

Front 2

A tread patterns that differs on each side and therefore is usually direction

Back 2

Asymmetric thread Patter

Front 3

A metric unit of measure for pressure

Back 3

Bar

Front 4

The part of the wheel the tire seals against

Back 4

Bead Seat

Front 5

A tire constructed in lattice or crisscross structure, with alternate plies crossing each other and laid with the cord angles in opposite direction

Back 5

Bias-Ply

Front 6

A network of cords that gives the tire shape and strength; also known as casting cords

Back 6

Casting Plies

Front 7

A switch that is only activate when centrifugal forces are placed on the vehicle.

Back 7

Centrifugal Switch

Front 8

A force between the tread and the road surface as a vehicle turn

Back 8

Cornering Force

Front 9

A wheel with negative offset, which gives the outside of the wheel a deep dish appearance. Deep dish refers to the side of the wheel that is farthest from the drop center

Back 9

Deep dish wheel

Front 10

A type of automated tire pressure monitoring system that measures tire pressure and possibly temperature via a sensor installed inside each wheel.

Back 10

Direct TPMS

Front 11

A tread pattern that is both directional and asymmetric, which means the tire is designed to rotate in only one direction and has one side that must face outward to ensure the tire perform as designed under operating conditions

Back 11

Directional and Asymmetric tread pattern

Front 12

A tread pattern designed to pump water out from under the tire; each tire must be placed in a particular spot of the vehicle

Back 12

Directional Tread Pattern

Front 13

A wheel design with part of the center section of the wheel a smaller diameter than the rest. It is used for mounting and demounting the tire

Back 13

Drop Center

Front 14

A tire imbalance that cause the wheel assembly to turn inward and outward with each half revolution

Back 14

Dynamic Imbalance

Front 15

A specialized rim design that is used with some run flat tires

Back 15

EH2 rim

Front 16

Tires with thick sidewalls that allows the tire to be driven even when it has no air pressure.

Back 16

Extended Mobility Technology (EMT)

Front 17

A type of lug nut that is flat where it bolts to the wheel and has a washer affixed that allows it to turn independent of the hex part of the lug nut.

Back 17

Flat seat with washer

Front 18

A type of lug nut that is flat where it bolts to the wheel.

Back 18

Flat seat without washer

Front 19

A type of automated tire pressure monitoring system that uses the anti lock braking system of the vehicle to measure the difference in the rotational speed of the four wheel to determine the tire pressure

Back 19

Indirect TPMS

Front 20

Nuts that secure the wheels onto the wheels studs

Back 20

Lug nut

Front 21

The process of matching up the tire's highest point with the rim's lowest point for the purpose of reducing the tire's radial runout.

Back 21

Match Mounting

Front 22

A condition in which the plane of the hub mounting surface is position towards the brake side or the back of the wheel center line

Back 22

Negative Offset

Front 23

A condition in which both the front and rear tires of the vehicle are experiencing the same slip angle

Back 23

Neutral Steer

Front 24

A tread pattern that is non specific, allowing the tire to be place on any wheel of the vehicle.

Back 24

Non directional Tread Pattern

Front 25

A condition in which the vehicle's front slip angle is larger than the rear slip angle. This vehicle is said to be pushing in the corners.

Back 25

Oversteer

Front 26

The diameter of the imaginary circle drawn through the center of the wheel bolt hole.

Back 26

Pitch Circle Diameter (PCD)

Front 27

A rating system that denotes the number of belt layers or plies that make up the tire's carcass. In Radial tire, the ply rating denotes the tire strength of the plies, not the actual number of plies.

Back 27

Ply Rating

Front 28

A condition in which the plane of the hub mounting surface is position towards the outside or toward the front of the wheel centerline

Back 28

Positive offset

Front 29

A tire with two or more layers of casting plies and cord loops running radially from bead to bead

Back 29

Radial Tire

Front 30

The outer circular lip of the wheel that help keeps the tire from popping off the wheel.

Back 30

Rim

Front 31

A tire design that allows the vehicle keep moving under driver control following a puncture or rapid loss of pressure.

Back 31

Run Flat Technology

Front 32

A rim designed with a slight hump at the inside edge of he bead ledges to hold the tire beads in place during a flat tire

Back 32

Safety type Drop Center rim

Front 33

A one way valve used in a valve stem

Back 33

Schrader Valve

Front 34

A tire construction with a flexible and malleable lining inside the tire around the inner tubeless membrane. The lining can seal small tread-area punctures instantly and permanently

Back 34

Self Sealing Tire

Front 35

The pressure on the wheel that pushes it toward the outside or inside of the rim as the vehicle makes a turn

Back 35

Side Force

Front 36

A tires sideways distortion that make the vehicle follow the path at an angle to the direction the road wheel is pointing

Back 36

Slip Angle

Front 37

A tire imbalance resulting from a heavy spot on a tire; it will vibrate vertically with the heavy area slapping the road surface with each turn of the wheel

Back 37

Static Imbalance

Front 38

A plain steel whee that is typically covered by a hubcap

Back 38

Steel disc type rim

Front 39

A tread pattern with the same tread pattern on both sides of the tire; typically nondirectional

Back 39

Symmetric tread pattern

Front 40

A type of lug nut with a tapered end toward the rim that helps center the wheel on the wheels studs

Back 40

Tapered Seat

Front 41

A standardized grading system that indicates the extent to which heat is generated of dissipated by the tire.

Back 41

Temperature Grade

Front 42

A measure of how strong a material is as it is being pulled apart

Back 42

Tensile Strength

Front 43

The level of air in the tire that provides it with load carrying capacity and affects overall vehicle performance.

Back 43

Tire inflation pressure

Front 44

A gauge used to measure tire pressure in a tire

Back 44

Tire Pressure Gauge

Front 45

An automated sensor system in most modern vehicles that alert driver of tire pressure problem

Back 45

Tire Pressure Monitoring System (TPMS)

Front 46

A valve through which air is inserted into a tire to inflate it

Back 46

Tire Valve

Front 47

A standardized grading system that indicates how well a tire will maintain contact with the road surface when wet

Back 47

Traction Grade

Front 48

The number imprinted on the sidewall of a tire by the manufactured a required by the National Highway Traffic Safety Administration (NHTSA) that indicates the tread life of a tire's tread.

Back 48

Tread wear grade

Front 49

A condition in which the vehicles front wheel turn sharper than the vehicle's direction when the vehicle is steered around the corner. The vehicle is said to be loose in the corners.

Back 49

Under Steer

Front 50

A Standardize grading system established by the National Highway Traffic Safety Administration (NHTSA) designed to provide tire buyers with a comparative measure of a tire's tread life, traction, and temperature characteristic.

Back 50

UTQG Uniform Tire Quality Grading

Front 51

A federal agency that regulates transportation safety in the united States, including vehicles wheels and tires. The DOT requires a code- a series of letters and numbers- to be stamped into the sidewall of every tire made for public use in the united states. These codes contain information such as the date of manufacture and the plant where the tire was manufactured

Back 51

DOT US Department of Transportation

Front 52

A one way spring loaded that screws into the valve stem that allows air to be pumped into a tire and prevents in from flowing out.

Back 52

Valve Core

Front 53

A rubber or steel piece that attaches the tire valve to the rim

Back 53

Valve Stem

Front 54

A cap that fits tightly onto the valve stem to prevent debris from clogging it and acts as a secondary seal

Back 54

Valve stem caps

Front 55

The process of matching the tire's lightest point with the rims heaviest point (generally at the valve stem) for the purpose of reducing the tire's imbalance

Back 55

Weight Matching

Front 56

The part of the wheels containing the holes for the lug studs

Back 56

Wheel Center

Front 57

Lug nuts used to hold the wheel on the hub

Back 57

Wheel Retaining Nuts

Front 58

The part on which the tire is mounted

Back 58

Wheel Rim

Front 59

The threaded fastener that attach the wheel to the vehicle

Back 59

Wheel Stud

Front 60

A condition in which the plane of the hub mounting surface is even with the center line of the hub

Back 60

Zero Offset