-Never mount used tires on yo ur vehicle if
you are not sure of their "previous histo
ry." Old used tires may have bee n 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 wh ich may be rep laced)
of automati c transmission, power steering,
power br akes, power wi ndows, power sea ts,
radio, and heater, to the ex tent that these
items are avai lab le as factory -installed equip
ment (whether installed or not).
Aspect ratio
means the ratio of the height to the w idt h of
the tire in percent. Numbers of 55 or lower in
d icate a low sidewall fo r improved s teer ing re
sponse and better overall handling on dry
pavement.
Bead
means the pa rt of the t ire that is made of
s teel wires, wrapped or re inforced by ply cor ds
and that is shaped to fit the r im.
Bead separation
means a b reakdown of the bond between
components in the bead.
Cord
means the strands forming the plies in the
tire.
Cold t ir e infl ation pr essure
means the tire pressure recommended by the
vehicle manufacturer for a t ire of a designated
size that has not been dr iven for more than a
couple of miles (kilometers) at low speeds in
the three hour period before the tire pressure i s measu red or adjusted.
Tire s an d wheel s 281
-If you notice un usua l 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
mea ns the weight of a motor ve hicle w ith
standard equipment includ ing t he maximum
capa city of fuel, o il, and coolant, ai r cond i
tion ing a nd addi tional weig ht o f optiona l
equipment .
Extra load tire
means a tire design to operate at higher loads
and at higher inflation pressures than the cor
respondi ng s tanda rd tire. Extra load tires may
be identified as "X L", "xl", "EXTRA LOAD", o r
"R F" on the sidewall .
Gross Axle Weight Rating ( "GAWR ")
mea ns the load-carrying capacity of a single
axle system, measured at the tire-ground in
te rfaces.
Gross Vehicle Weight Rating ( "GVWR ")
means the maximum total loaded we ight of
t h e ve hicle.
Groo ve
means the space between two adjacent tread
ribs.
Load rating (code )
means the maximum load tha t a t ire is rated
to carry for a given inflation pressure. Yo u
may not find this information on all tires be
ca use it is not required by law.
Maximum load rating
me ans the load r ating for a tire at the maxi
mum pe rm issi ble inflat ion pressure for that
ti re .
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