236 Tires and wheels
-Never mount used tires on yo ur vehicle if
you are not sure of their "previous histo
ry." Old used tires may have been dam
aged even though the damage cannot be
seen that can lead to sudden tire failure
and loss of vehicle control.
Glossary of tire and loading terminology
Accessory weight
means the comb ined weight (in excess of
those standard items which may be rep laced)
of automatic transmission, power steering, power brakes, power windows, power seats,
radio, and heater, to the extent that these
items are availab le as factory -installed equip
ment (whether installed or not) .
Aspect ratio
means the ratio of the he ight to the w idth of
the tire in percent. Numbers of 55 or lower in
dicate a low sidewall for improved steering re
sponse and better overall handling on dry
pavement.
Bead
means the part of the tire that is made of
steel wires, wrapped o r reinforced by ply cords
and that is shaped to fit the r im.
Bead separation
means a breakdown of the bond between
components in the bead.
Cord
means the strands forming the plies in the
tire.
Cold tire inflation pressure
means the tire pressure recommended by the
vehicle manufacturer for a tire of a designated size that has not been driven for more than a
couple of miles (kilometers) at low speeds in
the three hour period before the tire pressure
is measured or adjusted. -
If you notice unusual vibration or if the
veh icle pulls to one side when driv ing, a l
ways stop as soon as it is safe to do so and check the wheels and tires for dam
age.
Curb weight
means the weight of a motor vehicle w ith
standard equipment including the maximum
capacity of fuel, oil, and coolant, air condi
tioning and additional weight of optiona l
equipment.
Extra load tire
means a t ire design to operate at h igher loads
and at higher inflation pressures than the cor
responding standard tire. Extra load tires may
be identified as "XL", "xl", "EXTRA LOAD", or
"R F" on the sidewall .
Gross Axle Weight Rating ( "GAWR ")
means the load-carrying capacity of a s ingle
axle system, measured at the tire-ground in
terfaces .
Gross Vehicle Weight Rating ("GVWR")
means the maximum total loaded weight of
the vehicle.
Groove
means the space between two adjacent tread
ribs .
Load rating (code)
means the maximum load that a tire is rated
to carry for a given inflation pressure. Yo u
may not find this information on all tires be
cause it is not required by law.
Maximum load rating
means the load rating for a tire at the maxi
mum permissib le inflation pressure for that
tire.
