TYRE TERMS - BASIC
Understand the basic tyre terms spoken by your tyre dealer.
Understand the basic tyre terms spoken by your tyre dealer.
ALIGNMENT
When all wheels on the vehicle are adjusted so that they are pointed in the optimum direction relative to the road and each other.
BALANCE / IMBALANCEThe state in which a tyre and wheel spin with all their weight distributed equally. To correct an imbalance, a trained mechanic will add weights on the interior or exterior of the wheel.
BEAD
The section of the tyre that sits on the wheel. Inside, there is a round hoop of steel wires, wrapped or reinforced by body ply cords, that clamps the tyre firmly against the wheel rim.
CONTACT PATCH / FOOTPRINT
The area in which the tyre is in contact with the road surface. Also called footprint.
DEFLECTION
The tread and sidewall flexing where the tread comes into contact with the road.
GROOVE
The space between two adjacent tread ribs; also called tread grooves.
OVERSTEER
The tendency for a vehicle, when negotiating a corner, to turn more sharply than the driver intends. The rear end of the vehicle wants to swing toward the outside of a turn. A handling condition in which the slip angles of the rear tyres are greater than the slip angles of the front tyres. An oversteering car is sometimes said to be "loose," because its tail tends to swing wide.
PULL
A condition in which a vehicle swerves to one side without being steered in that direction, as a result of irregular tyre wear, improper front and/or rear wheel alignment, or worn or improperly adjusted brakes.
RIM / ALLOY / MAG
That portion of a wheel to which a tyre is mounted.
ROLLING RESISTANCE
The force required to keep a tyre moving at a uniform speed. The lower the rolling resistance, the less energy needed to keep a tyre moving.
ROTATION
The changing of tyres from front to rear or from side to side on a vehicle according to a set pattern; provides even tread wear. Rotating your tyres on a regular basis (every 10,000 km) is a simple way to add kilometers to their life.
RUN FLAT TECHNOLOGY
Tyre's that are designed to resist the effects of deflation when punctured, and to enable the vehicle to continue to be driven at reduced speeds and for limited distances.
SHOULDER
The area of a tyre where the tread and sidewall meet.
SIPES
Special slits within a tread block that open as the tyre rolls into the contact patch then close, breaking the water tension on the road surface and putting rubber in contact with the road to maintain adhesion, increasing wet and snow traction.
SUSPENSION
The various springs, shock absorbers and linkages used to suspend a vehicle's frame, body, engine, and drivetrain above its wheels.
SYMMETRICIAL TREAD DESIGN
Uniform tread pattern on both sides of the tread for better performance in specific conditions and on specific roads.
TYRE PLACARD
A metal or paper tag permanently affixed to a vehicle, which indicates the appropriate tyre size and inflation pressures for the vehicle. The placard can ordinarily be found on either the driver's or front passenger doorpost.
TRACTION
A metal or paper tag permanently affixed to a vehicle, which indicates the appropriate tyre size and inflation pressures for the vehicle. The placard can ordinarily be found on either the driver's doorpost, the glove box lid, or the fuel-filler door.
TREAD
That portion of a tyre that comes into contact with the road. It is distinguished by the design of its ribs and grooves. Provides traction in a variety of conditions, withstands high forces, and resists wear, abrasion, and heat.
TREAD LIFE
The life of a tyre before it is pulled from service; kilometers.
UNDERSTEER
The handling characteristic in which the front tyres break loose because they are running a larger slip angle than the rear tyres.
VALVE
A device that lets air in or out of a tyre. It is fitted with a valve cap to keep out dirt and moisture, plus a valve core to prevent air from escaping.
When all wheels on the vehicle are adjusted so that they are pointed in the optimum direction relative to the road and each other.
BALANCE / IMBALANCEThe state in which a tyre and wheel spin with all their weight distributed equally. To correct an imbalance, a trained mechanic will add weights on the interior or exterior of the wheel.
BEAD
The section of the tyre that sits on the wheel. Inside, there is a round hoop of steel wires, wrapped or reinforced by body ply cords, that clamps the tyre firmly against the wheel rim.
CONTACT PATCH / FOOTPRINT
The area in which the tyre is in contact with the road surface. Also called footprint.
DEFLECTION
The tread and sidewall flexing where the tread comes into contact with the road.
GROOVE
The space between two adjacent tread ribs; also called tread grooves.
OVERSTEER
The tendency for a vehicle, when negotiating a corner, to turn more sharply than the driver intends. The rear end of the vehicle wants to swing toward the outside of a turn. A handling condition in which the slip angles of the rear tyres are greater than the slip angles of the front tyres. An oversteering car is sometimes said to be "loose," because its tail tends to swing wide.
PULL
A condition in which a vehicle swerves to one side without being steered in that direction, as a result of irregular tyre wear, improper front and/or rear wheel alignment, or worn or improperly adjusted brakes.
RIM / ALLOY / MAG
That portion of a wheel to which a tyre is mounted.
ROLLING RESISTANCE
The force required to keep a tyre moving at a uniform speed. The lower the rolling resistance, the less energy needed to keep a tyre moving.
ROTATION
The changing of tyres from front to rear or from side to side on a vehicle according to a set pattern; provides even tread wear. Rotating your tyres on a regular basis (every 10,000 km) is a simple way to add kilometers to their life.
RUN FLAT TECHNOLOGY
Tyre's that are designed to resist the effects of deflation when punctured, and to enable the vehicle to continue to be driven at reduced speeds and for limited distances.
SHOULDER
The area of a tyre where the tread and sidewall meet.
SIPES
Special slits within a tread block that open as the tyre rolls into the contact patch then close, breaking the water tension on the road surface and putting rubber in contact with the road to maintain adhesion, increasing wet and snow traction.
SUSPENSION
The various springs, shock absorbers and linkages used to suspend a vehicle's frame, body, engine, and drivetrain above its wheels.
SYMMETRICIAL TREAD DESIGN
Uniform tread pattern on both sides of the tread for better performance in specific conditions and on specific roads.
TYRE PLACARD
A metal or paper tag permanently affixed to a vehicle, which indicates the appropriate tyre size and inflation pressures for the vehicle. The placard can ordinarily be found on either the driver's or front passenger doorpost.
TRACTION
A metal or paper tag permanently affixed to a vehicle, which indicates the appropriate tyre size and inflation pressures for the vehicle. The placard can ordinarily be found on either the driver's doorpost, the glove box lid, or the fuel-filler door.
TREAD
That portion of a tyre that comes into contact with the road. It is distinguished by the design of its ribs and grooves. Provides traction in a variety of conditions, withstands high forces, and resists wear, abrasion, and heat.
TREAD LIFE
The life of a tyre before it is pulled from service; kilometers.
UNDERSTEER
The handling characteristic in which the front tyres break loose because they are running a larger slip angle than the rear tyres.
VALVE
A device that lets air in or out of a tyre. It is fitted with a valve cap to keep out dirt and moisture, plus a valve core to prevent air from escaping.
TYRE TERMS - ADVANCED
Understand the more technical tyre terms spoken by your tyre dealer.
Understand the more technical tyre terms spoken by your tyre dealer.
ALL SEASON HIGH PERFORMANCE TYRES
Tyres that deliver a measure of traction on snow and ice without sacrificing dry performance driving capabilities.
ALL SEASON TYRES
Tyres that provide a good balance of traction in rain or snow with good tread life and a comfortable, quiet ride.
STEEL BELT
The combination of steel cords covered with rubber that forms a strip or belt placed under the tread rubber and on top of the casing (carcass); ensures uniformity when the tyre is rotating and helps prevent flats.
BELT
A rubber-coated layer of cords that is located between the body plies and the tread. Cords are most commonly made from steel but may also be made from fiberglass, rayon, nylon, polyester or other fabrics.
CORD
The strands of fabric forming the plies or layers of the tyre. Cords may be made from polyester, rayon, nylon, fiberglass or steel.
BIAS-PLY
A type of tyre with crossed layers of ply cord running diagonally to the center line of the tread.
CARCASS
The supporting structure of the tyre consisting of plies anchored to the bead on one side and running in a radius to the other side and anchoring to the bead. Also called casing.
CENTRE LINE
An imaginary line down the center of the vehicle. Alignment tracking is measured from this line.
CAMBER
A wheel's inward or outward tilt from vertical, measured in degrees. The camber angle is adjusted to keep the outside tyres flat on the ground during a turn.
CAMBER THRUST
Side or lateral force generated when a tyre rolls with camber, which can add to or subtract from the side force a tyre generates.
CASTER
The angle between a line drawn vertically through a wheel's centerline and the axis around which the wheel is steered; improves a car's directional stability and on-center feel.
TOE
The difference in distance between the front and rear of a pair of tyres mounted on the same axle.
TOE-IN
The fronts of two tyres on the same axle are closer than the rears of the tyres
TOE-OUT
The fronts of two tyres on the same axle are further apart than the rears of the tyres.
TOE-OUT TURNS
Also known as Ackerman Angle. A vehicle's wheels on the inside of a turn follow a smaller radius than the tyres on the outside of the turn, because the two front wheels steer at different angles when turning.
CARRYING CAPACITY
At a given air pressure, how much weight each tyre is designed to carry. For each tyre size, there is a load inflation table to ensure the inflation pressure used is sufficient for the vehicle axle load
OXIDATION
Rust process that takes place in the steel belts when moisture, via damage, is allowed to get inside the tyre. This can result in the tyre becoming unserviceable before normal replacement time.
Tyres that deliver a measure of traction on snow and ice without sacrificing dry performance driving capabilities.
ALL SEASON TYRES
Tyres that provide a good balance of traction in rain or snow with good tread life and a comfortable, quiet ride.
STEEL BELT
The combination of steel cords covered with rubber that forms a strip or belt placed under the tread rubber and on top of the casing (carcass); ensures uniformity when the tyre is rotating and helps prevent flats.
BELT
A rubber-coated layer of cords that is located between the body plies and the tread. Cords are most commonly made from steel but may also be made from fiberglass, rayon, nylon, polyester or other fabrics.
CORD
The strands of fabric forming the plies or layers of the tyre. Cords may be made from polyester, rayon, nylon, fiberglass or steel.
BIAS-PLY
A type of tyre with crossed layers of ply cord running diagonally to the center line of the tread.
CARCASS
The supporting structure of the tyre consisting of plies anchored to the bead on one side and running in a radius to the other side and anchoring to the bead. Also called casing.
CENTRE LINE
An imaginary line down the center of the vehicle. Alignment tracking is measured from this line.
CAMBER
A wheel's inward or outward tilt from vertical, measured in degrees. The camber angle is adjusted to keep the outside tyres flat on the ground during a turn.
CAMBER THRUST
Side or lateral force generated when a tyre rolls with camber, which can add to or subtract from the side force a tyre generates.
CASTER
The angle between a line drawn vertically through a wheel's centerline and the axis around which the wheel is steered; improves a car's directional stability and on-center feel.
TOE
The difference in distance between the front and rear of a pair of tyres mounted on the same axle.
TOE-IN
The fronts of two tyres on the same axle are closer than the rears of the tyres
TOE-OUT
The fronts of two tyres on the same axle are further apart than the rears of the tyres.
TOE-OUT TURNS
Also known as Ackerman Angle. A vehicle's wheels on the inside of a turn follow a smaller radius than the tyres on the outside of the turn, because the two front wheels steer at different angles when turning.
CARRYING CAPACITY
At a given air pressure, how much weight each tyre is designed to carry. For each tyre size, there is a load inflation table to ensure the inflation pressure used is sufficient for the vehicle axle load
OXIDATION
Rust process that takes place in the steel belts when moisture, via damage, is allowed to get inside the tyre. This can result in the tyre becoming unserviceable before normal replacement time.