PRINCIPLE OF OPERATION
WARNINGS
Vehicle modifications involving
braking system, aftermarket roof
racks, suspension, steering system,
tire construction and wheel and tire size
may change the handling characteristics
of your vehicle and may adversely affect
the performance of the AdvanceTrac
system. In addition, installing any stereo
loudspeakers may interfere with and
adversely affect the AdvanceTrac system.
Install any aftermarket stereo loudspeaker
as far as possible from the front center
console, the tunnel, and the front seats in
order to minimize the risk of interfering with
the AdvanceTrac sensors. Reducing the
effectiveness of the AdvanceTrac system
could lead to an increased risk of loss of
vehicle control, vehicle rollover, personal
injury and death. Remember that even advanced
technology cannot defy the laws of
physics. It’
s always possible to lose
control of a vehicle due to inappropriate
driver input for the conditions. Aggressive
driving on any road condition can cause
you to lose control of your vehicle
increasing the risk of personal injury or
property damage. Activation of the
AdvanceTrac system is an indication that
at least some of the tires have exceeded
their ability to grip the road; this could
reduce the operator ’s ability to control the
vehicle potentially resulting in a loss of
vehicle control, vehicle rollover, personal
injury and death. If your AdvanceTrac
system activates, SLOW DOWN. The AdvanceTrac with Roll Stability
Control system helps you keep control of
your vehicle when on a slippery surface.
The electronic stability control portion of
the system helps avoid skids and lateral
slides and roll stability control helps avoid
a vehicle rollover. The traction control
system helps avoid drive wheel spin and
loss of traction. See Using Traction
Control (page 139). Vehicle without AdvanceTrac
with RSC skidding off its
intended route.
A
Vehicle with AdvanceTrac with
RSC maintaining control on a
slippery surface.
B
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AA
B
BB
B
graded 100. The relative
performance of tires depends
upon the actual conditions of their
use, however, and may depart
significantly from the norm due to
variations in driving habits, service
practices, and differences in road
characteristics and climate.
Traction AA A B C
WARNING
The traction grade assigned
to this tire is based on
straight-ahead braking traction
tests, and does not include
acceleration, cornering,
hydroplaning or peak traction
characteristics. The traction grades, from highest
to lowest are AA, A, B, and C. The
grades represent the tire
’s ability
to stop on wet pavement as
measured under controlled
conditions on specified
government test surfaces of
asphalt and concrete. A tire
marked C may have poor traction
performance.
Temperature A B C WARNING
The temperature grade for
this tire is established for a
tire that is correctly inflated and
not overloaded. Excessive speed,
under-inflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure. The temperature grades are A
(the highest), B and C,
representing the tire
’s resistance
to the generation of heat and its
ability to dissipate heat when
tested under controlled conditions
on a specified indoor laboratory
test wheel. Sustained high
temperature can cause the
material of the tire to degenerate
and reduce tire life, and excessive
temperature can lead to sudden
tire failure. The grade C
corresponds to a level of
performance which all passenger
car tires must meet under the
Federal Motor Vehicle Safety
Standard No. 139. Grades B and A
represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law.
Glossary of Tire Terminology
• Tire label: A label showing the
OE (Original Equipment) tire
sizes, recommended inflation
pressure and the maximum
weight the vehicle can carry.
• Tire Identification Number
(TIN): A number on the
sidewall of each tire providing
information about the tire
brand and manufacturing
plant, tire size and date of
manufacture. Also referred to
as DOT code.
• Inflation pressure: A measure
of the amount of air in a tir
e.
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•
Standard load: A class of
P-metric or Metric tires
designed to carry a maximum
load at set pressure. For
example: for P-metric tires
35 psi (2.4 bar)
or 36 psi
(2.5 bar) depending on tire size
and for Metric tires
36 psi
(2.5 bar). Increasing the
inflation pressure beyond this
pressure will not increase the
tire capability.
• Extra load: A class of P-metric
or Me
tric tires designed to carry
a heavier maximum load at
42 psi (2.9 bar). Increasing the
inflation pressure beyond this
pressure will not increase the
tire ’s load carrying capability.
• bar Metric unit of atmospheric
pressure.
• kPa:
Kilopascal, a metric unit
of air pressure.
• PSI:
Pounds per square inch, a
standard unit of air pressure.
• Cold tire pressure:
The tire
pressure when the vehicle has
been stationary and out of
direct sunlight for an hour or
more and prior to the vehicle
being driven for 1 mi (1.6 km). •
Recommended inflation
pressure:
The cold inflation
pressure found on the Safety
Compliance Certification Label
(affixed to either the door hinge
pillar, door-latch post, or the
door edge that meets the
door-latch post, next to the
driver seating position) or Tire
Label located on the B-Pillar or
the edge of the driver door.
• B-pillar: The structural
member at the side of the
vehicle behind the front door.
• Bead area of the tire: Area of
the tire next to the rim.
• Sidewall of the tire:
Area
between the bead area and the
tread.
• Tread area of the tire: Area of
the perimeter of the tire that
contacts the road when
mounted on the vehicle.
• Rim: The metal support
(wheel) for a tire or a tire and
tube assembly upon which the
tire beads are seated.
Information Contained on the
Tire Sidewall
United States of America, and
Canada Federal regulations
require tire manufacturers to place
standardized information on the
sidewall of all tires. This
information identifies and
236 Transit (TTH) Canada/United States of America, enUSA, Edition date: 03/2014 Wheels and Tires
describes the fundamental
characteristics of the tire and also
provides a United States of
America DOT Tire Identification
Number for safety standard
certification and in case of a recall.
P Type Tires
P215/65R15 95H is an example of
a tire size, load index and speed
rating. The definitions of these
items are listed below.
Note:
Tire size, load index and
speed rating for your vehicle may
be different from the following
example. P: Indicates a tire,
designated by the Tire
and Rim Association, that
may be used for service on
cars, sport utility vehicles,
minivans and light trucks.
A
215: Indicates the nominal
width of the tire in
millimeters from sidewall
edge to sidewall edge. In
general, the larger the
number, the wider the tire.
B
65:
Indicates the aspect
ratio which gives the tire's
ratio of height to width.
C
R:
Indicates a radial type
tire.
D
237 Transit (TTH) Canada/United States of America, enUSA, Edition date: 03/2014 Wheels and TiresH
I
J
KL
M
A
B
CDEFG
E142543
15: Indicates the wheel or
rim diameter in inches. If
you change the wheel
size, you will have to
purchase new tires to
match the new wheel
diameter.
E
95:
Indicates the tire's
load index. It is an index
that relates to how much
weight a tire can carry.
You may find this
information in the Owner ’s
Guide. If not, contact a
local tire dealer.
F
H: Indicates the tire's
speed rating. The speed
rating denotes the speed
at which a tire is designed
to be driven for extended
periods of time under a
G
standard condition of load
and inflation pressure.
The tires on your vehicle
may operate at different
conditions for load and
inflation pressure. These
speed ratings may need
to be adjusted for the
difference in conditions.
The ratings range from 81
mph (130 kph) to 186 mph
(299 kph). These ratings
are listed in the following
chart. United States of
America DOT Tire
Identification Number
(TIN):
This begins with
the letters DOT and
indicates that the tire
H
meets all federal
standards. The next two
numbers or letters are the
plant code designating
where it was
manufactured, the next
two are the tire size code
and the last four numbers
represent the week and
year the tire was built. For
example, the numbers 317
mean the 31st week of
1997. After 2000 the
numbers go to four digits.
For example, 2501 means
the 25th week of 2001.
The numbers in between
are identification codes
used for traceability. This
information is used to
contact customers if a tire
defect requires a recall.
M+S or M/S: Mud and
Snow, AT: All Terrain, AS:
All Season.
I
Tire Ply Composition
and Material Used:
Indicates the number of
plies or the number of
layers of rubber-coated
fabric in the tire tread and
J
sidewall. Tire
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the driver door. The cold
inflation pressure should
never be set lower than
the recommended
pressure on the vehicle
label.
Tire speed ratings
mph ( km/h)
Letter
rating
81 mph (130 km/h)
M
87 mph (140 km/h)
N
99 mph (159 km/h)
Q
106 mph (171 km/h)
R
112 mph (180 km/h)
S
118 mph (190 km/h)
T
124 mph (200 km/h)
U
130 mph (210 km/h)
H
149 mph (240 km/h)
V
168 mph (270 km/h)
W
186 mph (299 km/h)
Y
Note: For tires with a maximum
speed capability over 149 mph
(240 km/h), tire manufacturers
sometimes use the letters ZR. For
those with a maximum speed
capability over 186 mph (299
km/h), tire manufacturers always
use the letters ZR. Note:
If the tire size does not begin
with a letter, this may mean it is
designated by either ETRTO
(European Tire and Rim Technical
Organization) or JATMA (Japan Tire
Manufacturing Association). You
may not find this information on all
tires because it is not required by
federal law.
Note: The tire suppliers may have
additional markings, notes or
warnings, for example standard
load, radial tubeless, etc.
T Type Tires
T145/80D16 is an example of a
tire size. T type tires have some
additional information beyond
those of P type tires. The
definitions of these items are
listed below.
Note: The temporary tire size for
your vehicle may be different from
this example. Tire Quality Grades
do not apply to this type of tire.
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T: Indicates a type of tire,
designated by the Tire
and Rim Association, that
is intended for temporary
service on cars,
sport-utility vehicles,
minivans and light trucks.
A
145: Indicates the
nominal width of the tire
in millimeters from
sidewall edge to sidewall
edge. In general, the larger
the number, the wider the
tire.
B 80: Indicates the aspect
ratio which gives the tire's
ratio of height to width.
Numbers of 70 or lower
indicate a short sidewall.
C
D:
Indicates a diagonal
type tire. R: Indicates a
radial type tire.
D
16:
Indicates the wheel or
rim diameter in inches. If
you change the wheel
size, you will have to
purchase new tires to
match the new wheel
diameter.
E
Additional Information for LT
Type Tires
LT235/85 R16 is an example of a
tire size. LT type tires have some
additional information beyond
those of P type tires. The
definitions of these items are
listed below.
Note: Tire Quality Grades do not
apply to this type of tire.
241 Transit (TTH) Canada/United States of America, enUSA, Edition date: 03/2014 Wheels and TiresA
BCDE
E142545
LT: Indicates a tire,
designated by the Tire
and Rim Association
(T&RA), that is intended
for service on light trucks.
A
Load Range and Load
Inflation Limits:
Indicates the tire's
load-carrying capabilities
and its inflation limits.
B Maximum Load Dual lb
(kg) at psi (kPa) cold:
Indicates the maximum
load and tire pressure
when the tire is used as a
dual, defined as four tires
on the rear axle (a total of
six or more tires on the
vehicle).
C
Maximum Load Single
lb (kg) at psi (kPa)
cold: Indicates the
maximum load and tire
pressure when the tire is
used as a single, defined
as two tires (total) on the
rear axle.
D
United States of America DOT
Tire Identification Number
(TIN)
United States of America, and
Canada Federal regulations
require tire manufacturers to place
standardized information on the
sidewall of all tires. This
information identifies and
describes the fundamental
characteristics of the tire and also
provides a United States of
America DOT Tire Identification
Number for safety standard
certification and in case of a recall.
This begins with the letters DOT
and indicates that the tire meets
all federal standards. The next
two numbers or letters are the
plant code designating where it
was manufactured, the next two
are the tire size code and the last
242 Transit (TTH) Canada/United States of America, enUSA, Edition date: 03/2014 Wheels and TiresA
BC
BDE142544