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250
Tires and wheels
Tread
means t hat port ion of a tire t hat comes into
con t act w it h t he road.
Tread separation
means pull ing away of the t read from the ti re
carcass .
Treadwear indicators (TWI)
means the projections within the pr incipal
grooves designed to give a visua l ind ication of
the deg rees of wea r of the tread . See
~
page 257, Tread Wear Indicator (TWI) for
mo re info rmat ion on me asu ring ti re wear.
Uniform Tire Quality Grading
is a tire information system developed by the
United States Nat io nal Highway Traffic Safety
Admi nistration (NHTSA) that is designed to
he lp buye rs make relat ive compa risons among
tires. The UTQG is not a safety rating an d not a
g ua ran t ee t hat a t ire will las t fo r a presc ribed
nu mbe r of m iles (kilome t ers) or perform in a
certain way. It s imply gives tire buye rs addi -
tional informat ion to com bine with ot her con -
side rat ions, s uch as pr ice, brand loya lty and
dea le r recommendations.
Under UTQG, t ires
are g raded by t he tire manufacturers
in three
areas: treadw ear, t ract io n, and temperature
res ista nce. The UTQG info rmation on the t ires ,
mo lded into t he s idewalls.
U.S. DOT Tire Identification Number (TIN)
This is the t ire's "serial number". It begins
with the lette rs "DOT" and indicates that the
t ire mee t s a ll fede ra l st andar d s. The nex t two
numbers o r letters indicate the plant where it
was man ufactu red, and the last four nu mbers
represent the wee k and year of man ufact ure.
For example,
DOT ... 2210 ...
me a ns t hat the t ire was produ ced in t he 22nd
wee k of 201 0. The ot he r num bers are m ar ket-
ing cod es that may or may not be used by the
t ire manufacturer . This information is used to
contact consume rs if a tire defect requires a
recall.
Vehicle capacity weight
me a ns t he ra t ed ca rgo an d luggage load plus
150 lb s. (68 kilog rams) times the vehicle's t o-
ta l seating capacity as listed on the la bel lo-
cated on the driver's side B-pilla r.
Vehicle maximum load on the tire
me a ns t hat load on a n individu al t ire th at is
de t ermined by dist ributi ng t o eac h axle its
share of the maxim um loa ded vehicle weight
and dividing by two .
Vehicle normal load on the tire
means t hat load on a n individu al tir e tha t is
de t ermined by dis t rib uti ng t o eac h axle its
share of the cur b weight , accessory weight,
and normal occ up ant weig ht (distr ibuted in
accordance with tab le be low ~ page 250)
and dividing by two.
Occupant loading and distribution for veh icle normal load fo r variou s designated seating
capacities
Designated seating capacity,
number of occupants
5
Vehicle normal load, number
Occupant distribution in a nor-
of occupants
_____
malty loaded vehicle
3
2 in front , 1 in back seat
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