3568-1. Specifications
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation
pressure
Tire pressure when the vehicle has been
parked for three hours or more, or has not
been driven more than 1 mile or 1.5 km under
that condition
Maximum inflation
pressureThe maximum cold inflated pressure to which
a tire may be inflated, shown on the sidewall
of the tire
Recommended
inflation pressureCold tire inflation pressure recommended by a
manufacturer
Accessory weight
The combined weight (in excess of those stan-
dard items which may be replaced) of auto-
matic transmission, power steering, power
brakes, power windows, power seats, radio
and heater, to the extent that these items are
available as factory-installed equipment
(whether installed or not)
Curb weight
The weight of a motor vehicle with standard
equipment, including the maximum capacity of
fuel, oil and coolant, and if so equipped, air
conditioning and additional weight optional
engine
Maximum loaded
vehicle weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant
weight150 lb. (68 kg) times the number of occupants
specified in the second column of Table 1
*
that follows
3578-1. Specifications
8
Vehicle specifications
Occupant distributionDistribution of occupants in a vehicle as speci-
fied in the third column of Table 1
* below
Production options
weight
The combined weight of installed regular pro-
duction options weighing over 5 lb. (2.3 kg) in
excess of the standard items which they
replace, not previously considered in curb
weight or accessory weight, including heavy
duty brakes, ride levelers, roof rack, heavy
duty battery, and special trim
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated
Rim diameter
(Wheel diameter)Nominal diameter of the bead seat
Rim size designationRim diameter and width
Rim type designationThe industry manufacturer’s designation for a
rim by style or code
Rim widthNominal distance between rim flanges
Vehicle capacity
weight
(Total load capacity)The rated cargo and luggage load plus 150 lb.
(68 kg) times the vehicle’s designated seating
capacity
Vehicle maximum load
on the tire
The load on an individual tire that is deter-
mined by distributing to each axle its share of
the maximum loaded vehicle weight, and
dividing by two
Vehicle normal load on
the tire
The load on an individual tire that is deter-
mined by distributing to each axle its share of
curb weight, accessory weight, and normal
occupant weight (distributed in accordance
with Table 1
* below), and dividing by two
Tire related termMeaning
