Glossary

Aramid

A synthetic fiber that is, per weight, stronger than steel. Used in tyre construction and provides excellent high tensile strength to weight.

Aspect Ratio

An expression representing the height of the sidewall of a tyre in terms of a percentage of tyre's width.

Asymmetric

When opposite sides of a tyre's tread pattern are not identical.

Glossary

Block Design

A tyre tread pattern made of raised rubber-compound segments.

Blocks

The individual, raised rubber-compound segments making up the tread of a tyre.

Buckling

A condition when a tyre is bulging or crumpling.

Glossary

Carcass

That portion of a tyre that is the foundation for the tread, belts, bead and sidewall.

Casing

The structure of tyre cords locked around wire beads.

Chafer

A finishing strip of calendered fabric used to protect the tyre's bead area from the rim.

Compound:The general term referring to the chemical formula for the tread material.

Glossary

Drive Wheel(s)

The wheel(s) that provide the power or driving force for a vehicle.

Glossary

Light Truck Tyres

Tyres designed for off-the-road and on/off-the-road use on sport/utility, small commercial and recreational vehicles.

Load Rating

A method of rating a tyre's load-carrying capacity (denoted by letters such as B, C, D, etc.) with respect to its ply rating.
A tyre sizing system using the section width (mm), aspect ratio, speed category, tyre construction and the rim diameter (inches). Example: 185/70SR13.

Low-Profile

A term describing a tyre with a low relative aspect ratio or series classification.

Glossary

P-metric System

A tyre sizing system using the section width (mm), aspect ratio, type of tyre construction and rim diameter (inches). Example: P225/70R15.

Passenger Car Tyre

Automobile tyres featuring aspect ratios of 70 or greater, using a taller profile for increased ride comfort.

Ply

A layer of rubber-coated fabric or wire making up the tyre casing.

Glossary

Ribs

Parts of a tyre tread pattern created by grooves that run circumferentially around the tyre.

Glossary

S-speed or S-performance rated

A speed category for tyres with a maximum speed capability of 180 km/h.

Series

A numerical representation of a tyre's aspect ratio; for example, 50 series.

Shoulder Blocks

Raised rubber-compound segments on the part of the tyre tread nearest the sidewall

Sipes

Slits in the tyre tread. Small cuts in the surface of the tread to improve traction.

Steel Belt

A belt material used in radial tyres. Its high stiffness provides good handling and low treadwear.

Steer Wheel(s)

The wheel(s) that direct the course of a vehicle.

Stud Holes

Small cavities along a tyre's tread designed to hold tyre studs for increased traction on snow-covered surfaces.

Glossary

UTQG

Uniform Tyre Quality Grade. A government-mandated tyre rating system based on a tyre's performance in treadwear durability, traction and temperature resistance. UTQG ratings are branded on a tyre's sidewall.

Glossary

V-Speed or V-Performance Rated

A speed category for tyres with a maximum speed capability of 240 km/h.

Varied-Pitch Ratio

Variations in angles and sizes of a tyre's tread elements that reduce ride noise levels.

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