Tyre information placard	A plate that specifies OE tyre size (original equipment), recommended tyre pressure and the maximum weight the car can carry.
Tyre identification number (TIN)	A number on the sidewall of each tyre with information about tyre brand and manufacturing plant, tyre size and date of manufacture.
Inflation pressure	A measurement of how much air is in the tyre.
Standard load	A class of P-metric or metric tyres designed for a maximum load at 35 psi1. The load-bearing capacity of the tyres does not increase if the tyre pressure is increased above this pressure.
Extra load	A class of P-metric or metric tyres designed for a heavier maximum load at 41 psi2. The load-bearing capacity of the tyres does not increase if the tyre pressure is increased above this pressure.
kPa	Kilopascal, a metric unit for air pressure.
psi	Pound per square inch, a standard unit for air pressure.
B-pillar	The beam on the side of the car behind the driver's door.
Bead area of the tyre	The tyre's surface area next to the wheel rim.
Sidewall of the tyre	The surface area between the base of the tyre and the tread.
Tread area of the tyre	The surface area of the tyre's circumference that has contact with the road when the tyre is fitted to the car.
Rim	Metal support (wheel) for a tyre or tyre and inner tube unit against which the base of the tyre seals.
Maximum load rating	A figure that specifies the maximum load in pounds and kilograms that the tyre can carry. This classification is made by the tyre manufacturer.
Maximum permissible inflation pressure	The maximum tyre pressure that the tyre should ever be subjected to. This limit is specified by the tyre manufacturer.
Recommended tyre inflation pressure	Tyre pressure, specified by Volvo, based on the type of tyres fitted to a car on delivery. This information is available on the tyre plate on the B-pillar on the driver's side and in the tyre pressure table.
Cold tyres	Tyres are considered cold when they have the same temperature as the surrounding air. This temperature is normally reached when the car has been parked for at least three hours.