Aspect ratio
Relationship between tire height and tire
widt hinp ercent. Tire pressure
This is pressur einside th etirea pplyin gan
outward force to eac hsquar einc hoft hetire's
surface. The tire pressur eisspecifie din
pounds per squar einc h( psi), in kilopascal
(kPa) or in bar. The tire pressur eshould only
be correcte dwhen th etires are cold. Tire pressure of cold tires
The tires are cold:
R if th evehicl ehas been parked without
direct sunligh tonthe tires for at least three
hours and
R if the vehicle has not been driven further
than 1mile (1.6 km) Tread
The part of the tire that comes into contact
with the road. Bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim. Sidewall
The part of the tire between the tread and the
bead. Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
part and more than 2.3 kg (5 lbs). These optional extras, such as high-performance
brakes, level control,
aroof rack or ahigh-
performance battery, are not included in the
curb weight and the weight of the
accessories. TIN (Tire Identification Number)
This is aunique identifier which can be used
by atire manufacturer to identify tires, for
example for aproduct recall, and thus identify
the purchasers. The TIN is made up of the
manufacturer's identity code, tire size, tire
type code and the manufacturing date. Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of atire. Traction
Traction is the result of friction between the
tires and the road surface. Treadwear indicators
Narrow bars (tread wear bars) that are
distributed over the tire tread. If the tire tread
is level with the bars, the wear limit of 0003in
(1.6 mm) has been reached. Occupant distribution
The distribution of occupants in avehicle at
their designated seating positions. Total load limit
Nominal load and luggage load plus
68 kilograms (150 lb) multiplied by the
number of seats in the vehicle. Definition of termsf
or tires and loading
335Wheels and tires Z
