From aspect ratio to virgin tyre, this glossary covers the essential terminology used in the commercial transport industry in Antigua and Barbuda. Use the search bar or jump to a letter below.
A
- Aspect Ratio
- The ratio between the sidewall height of a tyre and its section width, expressed as a percentage (for example, 75 in 295/75R22.5).
B
- Bead
- The reinforced steel-wire edge of a tyre that seats firmly against the wheel rim to maintain an airtight seal.
- Belt Package
- Steel cord plies positioned beneath the tread that stabilise the contact patch, resist punctures and improve handling.
- Bias Ply Construction
- A tyre construction in which the plies cross diagonally through the casing. Largely superseded by radial construction in commercial applications.
C
- Cap-and-Base Compound
- A dual-layer tread design that uses a harder top compound for wear resistance and a softer base layer for heat management.
- Casing
- The structural body of a tyre beneath the tread rubber, designed to withstand retreading and deliver multiple service lives.
- Closed Shoulder
- A tread design in which the outer ribs are connected, reducing stone retention and uneven wear on drive-axle tyres.
- CPM / CPK (Cost Per Kilometre)
- Total tyre cost divided by the total kilometres travelled before removal. The standard metric for comparing the value of commercial tyres.
D
- DOT Code
- A serial number moulded into the sidewall identifying the manufacturer, production plant, tyre size and date of manufacture.
- Drive Position
- The rear drive axle position or positions of a commercial truck, requiring tyres with deep, aggressive tread for maximum traction.
- Dual Assembly
- A configuration in which two tyres are mounted side by side on a single hub, common on drive and trailer axles.
F
- FMVSS
- Federal Motor Vehicle Safety Standards — US-origin standards governing tyre performance, labelling and safety requirements. In Antigua and Barbuda, tyre safety requirements are overseen by the Ministry of Works and Transport.
- Footprint
- The area of the tread in contact with the road surface at any given moment under load.
G
- Grooves
- Channels moulded into the tread surface to evacuate water, dissipate heat and provide biting edges to improve traction.
H
- HATT
- Hanksugi Advanced Tire Technology — a proprietary engineering platform that optimises tread compounds, bead strength and casing geometry for extended mileage and retreadability.
I
- Inflation Pressure
- The air pressure inside a tyre, measured in PSI. Correct inflation is critical for load capacity, tread wear and fuel performance.
- Uneven Wear
- Irregular erosion of the tread caused by misalignment, incorrect inflation, mechanical problems or tyres operated in the wrong position.
L
- Load Index
- A numerical code indicating the maximum weight a tyre can safely carry at its rated inflation pressure.
- Load Range
- A letter designation (G, H, J, L) representing the ply-rating equivalent of a tyre and its maximum inflation pressure.
- LRR (Low Rolling Resistance)
- Tyres designed to minimise the energy lost through deformation as the tyre rolls, directly improving fuel performance.
- Lug Pattern
- A tread design with deep lateral grooves for aggressive traction, commonly used on drive axles and off-highway applications.
M
- M+S (Mud and Snow)
- A sidewall marking indicating that the tread meets Rubber Manufacturers Association standards for traction in mud and light snow.
P
- Ply Rating
- A traditional measure of tyre strength indicating the cord ply count supporting the load. Now superseded by the Load Range designation system.
- PSI
- Pounds per square inch — the standard unit of measurement for tyre inflation pressure used in Antigua and Barbuda.
R
- Radial Construction
- A tyre structure in which the plies run perpendicular to the direction of travel, providing even wear and flexible sidewalls.
- Retread
- The process of buffing a worn casing and applying new tread rubber, extending tyre service life at a significantly lower cost.
- Rib Pattern
- A tread design with continuous circumferential grooves, optimised for long highway mileage and even wear on steering axles.
- Rolling Resistance
- The energy a tyre consumes through internal friction as it rolls under load. Lower values translate directly into better fuel performance.
S
- Sidewall
- The vertical section between the tread and the bead, which carries the tyre size, load rating, DOT code and manufacturer markings.
- Siping
- Fine cuts made in tread blocks to create additional biting edges, improving wet traction and reducing the risk of aquaplaning.
- SmartWay
- An EPA verification programme certifying that tyres meet standards for fuel savings and emissions reduction.
- Speed Rating
- A letter code (for example, L or M) indicating the maximum sustained speed at which a tyre can operate safely under load.
- Steer Position
- The steering axle of a commercial truck, requiring tyres optimised for precise handling, lateral stability and even tread wear.
- Stone Ejectors
- Small raised rubber elements moulded into tread grooves, designed to prevent stones from becoming embedded and damaging the casing.
T
- TPMS
- Tyre Pressure Monitoring System — electronic sensors that continuously monitor tyre pressure and alert drivers when it falls below safe levels.
- Trailer Position
- Non-drive axle positions on trailers, requiring tyres designed to resist lateral scrub and minimise rolling resistance.
- Tread Compound
- The specific rubber formulation of the tread surface, engineered to balance wear resistance, traction and heat dissipation.
- Tread Depth
- The measurement from the top surface of the tread to the bottom of the deepest groove, measured in thirty-seconds of an inch.
U
- UTQG
- Uniform Tyre Quality Grading — a DOT classification system rating tread wear, traction and temperature resistance, primarily for passenger tyres.
V
- Virgin Tyre
- A brand-new tyre that has never been used or retreaded, also referred to as a new casing.
