Wheel & tire terms, defined

A11

• Air Pressure Air pressure is the amount of compressed air inside a tire, usually measured in PSI, or pounds per square inch. It helps…
• Air-Down Air-down means reducing tire air pressure below the normal road-driving PSI to improve traction, comfort, and control in off-road conditions. This technique…
• All-Season Tires All-season tires are designed to provide balanced performance in a broad range of mild driving conditions.
• All-Season Tires All-season tires are tires designed to provide balanced performance in a wide range of everyday driving conditions, including dry roads, wet roads,…
• All-Terrain Tires All-terrain tires (A/T tires) are tires designed to deliver dependable performance both on paved roads and off-road terrain. They combine many of…
• All-Weather Tires All-weather tires are tires engineered to provide reliable performance throughout the entire year, including dry roads, wet pavement, light snow, and colder…
• Anti-Roll Bar An anti-roll bar, also called a sway bar or stabilizer bar, is a suspension component that helps reduce body roll when a…
• Aquaplaning Aquaplaning, also known as hydroplaning, happens when a layer of water builds up between a tire and the road surface, causing the…
• Aspect Ratio A tire’s aspect ratio expresses sidewall height as a percentage of the tire’s nominal section width.
• Aspect Ratio Aspect ratio is the relationship between a tire's sidewall height and its width, expressed as a percentage. It is one of the…
• Asymmetrical Tread An asymmetrical tread is a tire tread design where the inner and outer sections of the tread have different patterns and perform…

B3

• Backspacing Wheel backspacing is the distance from the mounting surface to the wheel’s inner edge and helps describe inboard clearance.
• Bead The tire bead is the reinforced inner edge that seats against the wheel and helps create an airtight, secure connection.
• Belted Tire A belted tire is a tire built with reinforcing belts placed beneath the tread area to improve strength, stability, and tread support.…

C2

• Camber Camber is the inward or outward tilt of a wheel when viewed from the front of the vehicle.
• Caster Caster is the forward or rearward tilt of the steering axis when viewed from the side of a vehicle.

F1

• Forged Wheels Forged wheels are shaped from solid metal under high pressure to create a dense, strong wheel structure.

H1

• Hydroplaning Hydroplaning occurs when water separates a tire from the road surface and reduces available steering, braking and acceleration grip.

L1

• Load Index A tire’s load index is a numerical code corresponding to the maximum load the tire can carry under specified conditions.

O2

• Offset Offset is the distance between a wheel’s mounting surface and its centreline, normally measured in millimetres. What wheel offset means ... Why offset matters…
• Offset Wheel offset is the distance between a wheel’s mounting surface and its centreline, normally measured in millimetres.

R1

• Rolling Resistance Rolling resistance is the energy a tire loses as it deforms and recovers while moving under load.

S2

• Sidewall A tire sidewall is the flexible section between the tread and bead that carries markings and helps absorb road impacts.
• Steel Wheels Steel wheels are durable wheels formed from stamped steel sections and commonly used for practical or winter applications.

T2

• Tire Pressure Tire pressure is the amount of air inside a tire, measured in PSI or kPa and checked when the tires are cold.
• Tire Rotation Tire rotation is the planned movement of tires between vehicle positions to promote more even tread wear.

W1

• Winter Tires Winter tires use cold-weather compounds and specialized tread features to improve traction in snow, slush and icy conditions.