The checking and adjustment of caster, camber and toe angles in a vehicle's suspension to
maintain specifications engineered by the vehicle manufacturer for optimum performance.
Aspect ratio
The relationship between the section height and section width of a tyre expressed as a percentage of section width.
If the section height is one half the section width, the aspect ratio is 50%
Balance
The equal distribution of the mass of the tyre and wheel assembly for smooth driving.
Balance is achieved by fitting weights to the wheel rim to offset uneven weight distribution
of the tyre or wheel.
Bead
High-tensile steel wires are used to create the robust, inextensible loop that is the bead. It firmly holds the Tyre on the wheel
rim by anchoring the Tyre plies and fitting snugly on the rim seat.
Bead seat
The tyre bead sits on the inner ledge of the wheel rim, which is located next to the rim flange.
This ensures a tight seal and aids in keeping the tyre firmly in place.
Belts
Under the tread, the Tyre belt is made up of sturdy string plies that aid to maintain the Tyre's
shape and prevent deformation from centrifugal forces during braking, cornering, and high-speed rotation.
Bias-ply
A bias-ply Tyre has plies that cross one another at opposite angles and run diagonally
from bead to bead. This cross-ply design, which is frequently found in older or heavier vehicles,
offers strength and flexibility.
Camber
Camber is the angle, as viewed from the front of the car, between the centerline of the Tyre and a vertical line.
It impacts the vehicle's overall stability, cornering ability, and tyre wear.
Camber thrust
The cornering force generated by a Tyre's camber angle is known as camber thrust. During turns, particularly when the tyre is leaning inward or outward, this force aids the vehicle keep stability and grip.
Casing
The interior structure composed of fabric plies is called the tyre casing, or carcass.
It maintains strength and flexibility when driving, supports loads, and gives the tyre its form.
Caster
Caster is the angle, as seen from the side of the car, between the steering axis and a vertical line. During driving,
it impacts self-centering, steering stability, and overall handling performance.
Compounding
The combining of five basic ingredients: rubber, carbon black, plasticizers, curing materials,
and ozone retardants to form the tread and other "rubber" components of a tyre.
Cornering force
A tyre's lateral frictional force during a turn is known as the cornering force.
While turning at different speeds, it helps the car stay stable and maintain grip by opposing the centrifugal force.
Crown
The middle section of a tyre's tread, known as the tread center, is mostly in charge of providing straight-line traction, stability, and even wear when traveling on highways or at high speeds on dry roads.
Deflection
The difference between a tyre's unloaded and loaded radii is known as deflection. It shows the amount of compression the tyre experiences under load, which impacts handling and ride comfort.
Directional stability
In order to ensure better handling and more control when driving, a tyre's directional stability refers to its capacity to maintain its directed course independent of surface irregularities or road shapes.
Footprint
The area of a tyre's tread that comes into contact with the ground is called the contact patch. It is essential for handling, braking, traction, and spreading the vehicle's load equally when driving.
Harmonic marking
In order to align high and low points during match mounting, tyres and wheels with harmonic marks serve as reference points. This lessens runout, which lessens vibration and enhances balance and ride comfort.
Hoop strength
Hoop strength is the ability of a tyre's belt construction to withstand centrifugal force while in rotation. It guarantees dimensional stability, preserving performance and form at high speeds.
Hydroplaning
The accumulation of water in a film under the footprint that causes a tyre to lift from the road surface, losing traction. Hydroplaning is affected by vehicle speed; tread pattern, and water depth.
Imbalance
The condition that exists when a tyre's mass is not evenly distributed around the rolling axis and centerline, causing bounce (static imbalance) or shake (dynamic imbalance).
Inflation pressure
Tyre cord tensile stress is caused by inflation pressure, which is the air pressure within a tyre. The tyre can carry the weight of the vehicle and keep its correct shape and performance thanks to this pressure.
Liner or inner-liner
The thin layer of halo butyl rubber inside a tyre that contains the inflation air, sometimes called the inner-liner. All tubeless tyres are manufactured with an inner-liner.
Mixing tyres
Fitting tyres of different sizes or constructions to a vehicle. Mixing should be avoided. Some performance vehicles, however, specify different size tyres on front and rear axles.
Mounting tyres
The procedure of attaching a tyre to the wheel rim is known as mounting. Its safe, balanced, and effective operation depends on correct alignment, pressure checks, and rotation direction awareness.
Overall diameter
An unloaded, inflated tyre's overall diameter is the distance between its tread crowns. It aids in size and is also known as outside diameter; the free radius is half of this value.
Over inflation
A tyre that is over-inflated will have less grip, uneven wear, and a rougher ride because it is inflated over the recommended amount by the vehicle manufacturer or above the pressure appropriate for the actual load.
Oversteer
A handling condition known as oversteer occurs when the rear tyres lose their traction before the front tyres do, forcing the car to swing outward during a turn. If left unchecked, this can result in a spin.
Plies
The reinforcing members of a tyre composed of layers of cord fabric and rubber that provide the strength to contain the air pressure needed to support a load and resist deflection.
Radial
The tyre construction utilizing plies that run radially from bead to bead under the tread. This construction requires a belt to stabilize the tread and define the tyre diameter.
Revolutions per km
The number of revolutions per km is the number of times a tyre rotates during a 1 Km trip. In addition to tracking fuel efficiency, this parameter aids in vehicle tyre size matching and speed calibration.
Rim
The area of the wheel that contains the flanges, bead seats, and well is called the rim. It offers the support that a tyre is mounted on, guaranteeing a tight fit and adequate sealing.
Rim diameter
Rim diameter refers to the measurement across the bead seats where the tyre mounts. It’s typically expressed in inches for passenger vehicles and determines the compatible tyre size for proper fitting.
Rim width
The space between the inner surfaces of the rim flanges—where the tyre beads are located is known as the rim width. It has a significant impact on handling, tyre fitment, and overall driving performance.
Rollover
Rollover can compromise vehicle stability, handling, and tyre integrity when a tyre's sidewall flexes too much during a hard corner and makes contact with the road.
Rotation
The deliberate moving of tyres between locations on a car to encourage uniform tread wear, increase tyre life, and preserve balanced performance is known as rotation. It is essential to tyre care.
Run out
A tyre slice that runs from one bead to the other through the tread.The word "section" refers to a tyre cross-section when one bead pierces the tread and sidewall to reach the other bead.
Section
A slice of a tyre from one bead, through the tread to the other bead.The term "section" describes a cross-section of a tyre that shows one bead going through the tread and sidewall to the other bead.
Section height
In an empty tyre, section height is the vertical distance from the bead seat and the crown, or upper center of the tread. In determining the performance and profile of tyres, it is crucial.
Section width
Section Width is the distance between two sidewalls at the widest point of the tyre. It has a direct impact on handling, ride quality, and vehicle clearance and varies according to rim width.
Series
The term "series" describes a tyre's aspect ratio, or the sidewall's height
in relation to its width. The sidewall height of a 60 series tyre, for instance, is 60% of its width.
Shoulder
The tyre's tread edge where it connects to the sidewall. Where the tread joins the sidewall, it forms the tyre's shoulder. In addition to helping with force distribution during braking and turning.
Sidewall
The area between tread and bead is called sidewall. In order to provide stable driving, it flexes to absorb road shocks while maintaining adequate firmness to sustain cornering forces and prevent tyre rollover.
Slip angle
The angle that separates a Tyre's actual route of travel from its steering direction. It influences how the tyre grips the road and helps with vehicle handling when it happens during cornering.
Speed rating
A tyre's maximum speed capability, as established by indoor testing, is indicated by a letter designation. A particular speed range is represented by each letter; for a reference, consult the speed-rating table.
Toe
the discrepancy in alignment between the tyres' front and back edges on an axle. Front margins are closer when toed in (tyres point inward); they are wider apart when toed out (tyres point outward).
Tread
The area of a tyre that makes contact with the earth. Its long-lasting rubber mold offers excellent traction and is made to withstand wear for enhanced longevity and performance.
Tread pattern
The precise configuration of the tread's blocks, channels, sipes, and grooves. This design promotes performance in a variety of road and weather conditions while increasing traction and grip.
Tread void
Tyre tread features that let water escape from the contact patch, such as channels and grooves, help preserve traction and lower the chance of hydroplaning.
Treadwear
A measurement of the anticipated tread life of a tyre under typical driving circumstances. It shows how long the tyre's surface that comes into contact with the road will last.
Tubeless
A tyre design that eliminates the need for an external inner tube by preventing air leaks through a rubber inner liner inside the casing, improving efficiency and safety.
Underinflation
The condition that exists when there is not sufficient air pressure in a tyre to support a specific load. This causes the tyre to operate with excessive deflection and rollover.
Understeer
This problem happens when the front tyres lose their traction before the rear tyres do, leading the car to continue straight ahead instead of curved as intended.
Wheel alignment
Wheel alignment ensures equal wear, improved handling, and fuel efficiency by adjusting tyre angles to the manufacturer's specifications. For smooth, secure driving, camber, toe, and caster settings are used.
