RFT (Run-Flat Technology) Tires:In addition to the above, there are
recommendations specific to the repair of RFT tires; see “RFT Tires with
Run-Flat Technology” in this manual.
TIRE MOUNTING AND OTHER SERVICING
WARNING!
Removing and replacing tires on wheels can be dangerous.
Attempting to mount tires with improper tools or procedures may
result in a tire explosion causing serious personal injury or death.
This is only a job for a qualified tire service professional. Never
perform tire service procedures without proper training, tools, and
equipment.
This manual is not intended to provide proper training or service
procedures for tire mounting, demounting, balancing, rotation, or
repair. Please leave these tasks to qualified tire service professionals.
For your safety and that of others:
•Always stand well clear of any tire mounting operation. This is
especially important when the service operator inflates the tire. If the
tire has been improperly mounted, it may burst with explosive force
causing serious personal injury or death.
•Tires must match the width and diameter requirements of the wheels.
For example, 16 inch diameter tires must only be mounted to 16 inch
diameter wheels. Radial tires must only be mounted to wheels
approved for radial tires.
•Wheels must be free of cracks, dents, chips, and rust. Tires must be free
of bead damage, cuts, and punctures.
•Never inflate a tire beyond 40 psi (275 kPa) to seat the beads. Be
absolutely certain beads are fully seated before adjusting inflation
pressure to the level recommended for vehicle operation.
•Never put flammable substances in tire/wheel assemblies at any time.
Never put any flammable substance into a tire/wheel assembly and
attempt to ignite to seat the beads.
•Always stand well away from the work area when tires are being spin
balanced either on or off the vehicle.
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HIGH PERFORMANCE, LOW ASPECT RATIO TIRES
Many new vehicles come equipped from the factory with high perfor-
mance and/or low aspect ratio tires. Generally, these tires provide
increased vehicle handling capability, but may also have numerous
engineering performance trade-offs associated with their designs.
•Low aspect ratio tires, with reduced sidewall height, may be more
susceptible to damage from potholes, road hazards, and other objects
such as curbs. This is true for the wheels as well. Therefore, as with all
other tires, it is important to drive with care and maintain proper
inflation pressure and load conditions. See “Tire Inflation Pressure”
and “Tire Damage, Inspection and Service Life” in this manual.
•Some sports cars and other handling performance enhanced vehicles,
including sedans and light trucks/SUVs, may be originally equipped
with high performance tires that are more optimized for warmer
weather use. Colder, winter weather traction may be reduced for these
types of tires. Winter tires may be recommended by the vehicle
manufacturer for colder weather application. See “Winter Tires,” the
next section in this manual.
•High performance tires may also wear more quickly, ride more firmly,
and produce more noise during operation.
Consult your vehicle owner ’s manual and tire information placard, or a
qualified tire service professional, for more information and specifics
regarding these types of tires.
WINTER TIRES
WARNING!
Winter driving presents special challenges for vehicle mobility. The
use of winter tires (including studs and chains)—while improving
traction performance in snow and ice—requires special care with
regard to acceleration, braking, cornering, and speed. It is important
to drive with care, not only on snow and ice, but on dry and wet
roads as well.
In winter driving conditions, vehicle control and safe operation under
braking and cornering is especially dependent upon the rear tires. For
this reason, winter tires are best applied to all wheel positions. Some
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•High-speed driving should be left to trained professionals operating
under controlled conditions.
•No tire, regardless of its design or speed rating, has unlimited capacity
for speed, and a sudden tire failure can occur if its limits are exceeded.
See “Tire Speed Ratings,” the next section in this manual.
Refer to your vehicle owner ’s manual for any tire pressure recommen-
dations for high speed driving.
TIRE SPEED RATINGS
A tire bearing a letter “speed rating” designation indicates the tire’s
speed capability according to standardized laboratory tests. This speed
rating system is intended to permit comparison of the speed capabilities
of different tires. When replacing your tires, consult your vehicle owner ’s
manual and tire information placard for recommendations, if any,
concerning the use of speed rated tires.
•To avoid reducing the speed capability of the vehicle, replace a speed
rated tire only with another tire having at least the same speed rating.
It is the “top speed” of the “slowest” tire on the vehicle which limits
the vehicle’s top speed without tire failure.
•The tire’s speed rating is void if the tire is repaired, retreaded,
damaged, abused, or otherwise altered from its original condition.
Thereafter, it should be treated as a non-speed rated tire.
•Non-speed rated tires are usually for ordinary passenger car or light
truck service and not for high speed driving.
•For winter tires used in cold weather conditions, it is generally
acceptable to apply a tire with a lower speed rating than your original
tires; however, speed should be reduced accordingly. All winter tires
should be the same speed rating. Some vehicles have specific recom-
mendations regarding winter tire use; consult your vehicle owner ’s
manual and tire information placard. See “Winter Tires” in this
manual.
These speed ratings are based on standardized laboratory tests under
specific, controlled conditions. While these tests may relate to perfor-
mance on the road, real-world driving is rarely identical to any test
conditions. Your tire’s actual speed capability may be less than its rated
speed since it is affected by factors such as inflation pressure, load, tire
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condition (including damage), wear, vehicle condition (including align-
ment), driving conditions, and duration at which the speed is sustained.
Use the following chart to compare the speed ratings of tires.
Speed
SymbolSpeed Category*
mph km/h
M81130
Q99160
R 106 170
S 112 180
T 118 190
U 124 200
H 130 210
V 149 240
Z** >149 >240
W 168 270
Y 186 300
(Y)** >186
The tire’s speed rating designation appears on the tire sidewall with the
tire size. Examples:
P275/40ZR17 max > 149 mph (240 km/h)****
P275/40R17 93W max = 168 mph (270 km/h)
P275/40ZR17 93W max = 168 mph (270 km/h)
P275/40ZR17 93Y max = 186 mph (300 km/h)
P275/40ZR17 93(Y) max > 186 mph (300 km/h) ****
* In standardized laboratory tests that relate to highway speeds. Actual
tire speed and performance capability depend on factors such as inflation
pressure, load, tire condition, wear, and driving conditions.
** Any tire having a maximum speed capability above 149 mph
(240 km/h) may, at the tire manufacturer ’s discretion, include a “Z” in
the size designation (i.e. P275/40ZR17).
*** For tires having a maximum speed capability above 186 mph
(300 km/h), a “Z” must appear in the size designation and a “Y” marked
in brackets (as shown) in the service description.
**** Consult the tire manufacturer for maximum speed capability.
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YOUR SPARE TIRE
Consult your vehicle owner ’s manual for proper application of your
spare tire. Your car may be equipped with a “temporary use” spare tire;
this spare may differ in size and construction from the other tires on your
vehicle.
WARNING!
Check inflation pressure before use. Failure to have proper inflation
pressure when using your spare tire can result in serious personal
injury or death. See Tire Inflation Pressure in this manual.
WARNING!
Mounting a “temporary use” tire on a wheel which is not
specifically designed for it, or placing another type tire on a wheel
designated for temporary use can be dangerous. Your vehicle’s
handling characteristics can be seriously affected. You could have an
accident resulting in serious personal injury or death. Consult your
vehicle owner ’s manual for proper application of your “temporary
use” spare tire.
The spare tire in your vehicle is intended to be used as a spare when
needed. The spare tire carrier is not intended to be used for long term
storage, except for “temporary use” tires. If your spare is the same size,
load rating, and type of tire as your road tires, it should be included in the
tire rotation process; see “Radial Tire Rotation” in this manual for more
information.
The spare should be included in regular tire inspections and inflation
pressure checks. In addition, it should be replaced 10 years after date of
manufacture, regardless of condition or tread depth. For more informa-
tion, see the “Tire Damage, Inspection and Service Life” in this manual.
TIRE STORAGE
Tires should be stored indoors in a cool, dry place where water cannot
collect inside them. Tires should be placed away from electric
generators/motors and sources of heat such as hot pipes. Storage
surfaces should be clean and free of grease, gasoline or other substances
which can deteriorate the rubber.
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RFT TIRES WITH RUN-FLAT TECHNOLOGY
If your vehicle is equipped with
Bridgestone or Firestone brand RFT
tires, this chapter presents specific
maintenance and safety issues asso-
ciated with these tires that are in addition to those covered elsewhere in
this manual.
What is RFT? Run-Flat Technology tires are extraordinary tires that
utilize specially designed components to temporarily support your
vehicle in the event of inflation pressure loss, such as from a puncture.
This gives you the ability to drive to a convenient and safe location to
change your tire (if equipped with a spare) or have it inspected for
possible repair or replacement.
Naturally, certain run-flat and low pressure operating limitations apply,
which varies according to the specific self-supporting tire design. Like all
tires, during normal operation, they must be properly inflated and
maintained. Regardless of the design or quality, no tire is indestructible.
RFT—How to Identify:Bridgestone and Firestone brand tires are
marked on the sidewalls, near the wheel, with the RFT logo (shown
above).
RFT INFLATION PRESSURE
Like other tires, RFT tires need proper inflation pressure maintenance for
safe operation and to achieve the maximum tire life and performance.
Check inflation pressures monthly and before long trips or carrying extra
weight. Use an accurate tire gauge and check pressures when the tires are
cold. Follow the vehicle manufacturer ’s recommendation for inflation
pressure settings as indicated on the vehicle tire information placard
and/or in the vehicle owner ’s manual. Do not forget the spare, if
applicable. See “Tire Inflation Pressure” in this manual.
TIRE PRESSURE MONITORING SYSTEM (TPMS)
A functioning tire pressure monitoring system (TPMS) must be used with
your RFT tires. Because these tires ride so well even without inflation
pressure, the TPMS may be necessary to alert you of an inflation pressure
loss condition. When alerted, follow the instructions in your vehicle
owner ’s manual and see “Run-Flat or Low Tire Pressure Operation,” the
following section in this manual.
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The vehicle or TPMS manufacturer may advise checking the TPMS
regularly to confirm it is in working order. In addition, a new pressure
sensor, certain components, or reprogramming may be necessary when a
tire is serviced. Consult your vehicle owner ’s manual, vehicle manufac-
turer, or a Bridgestone Firestone Run-Flat Certified Retailer for questions
regarding TPMS operation and service.
RUN-FLAT OR LOW TIRE PRESSURE OPERATION
WARNING!
Serious personal injury or death may result from a tire failure or
accident due to improper run-flat or low tire pressure operation.
Read and follow the instructions below, and the other maintenance
and safety recommendations elsewhere in this manual.
General Instructions
The Tire Pressure Monitoring System (TPMS) required in your vehicle
may have different methods of alerting you when your tire has lost
inflation pressure. The international standard for the definition of run-flat
operation is pressure at or below 10 psi (70 kPa); however, some vehicle
manufacturers may have established a different pressure limit. Consult
your vehicle owner ’s manual for the details of your TPMS. Once the
TPMS has indicated that a tire has reduced inflation pressure, the run-flat
mode of operation has commenced. During this phase of operation,
please follow these instructions:
•Reduce speed as much as safely and reasonably possible; do not
exceed 50 mph (80 km/h).The greater the speed, the less distance the
tire can travel.
•Avoid abrupt or aggressive acceleration, braking, or cornering ma-
neuvers as much as safely and reasonably possible.Pot holes and
other road hazards should be avoided. Careful driving limits potential
damage to the tire, wheel, and vehicle.
•Proceed to a safe and convenient location for tire service as soon as
possible.Take note of your mileage; your operation distance is limited.
SeeDistance—How Far You Can Drive,” the next section in this
manual.
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•If an unusual vibration or vehicle handling difficulty arises, stop
driving as soon as safely and reasonably possible.The tire may be
about to suddenly fail. Release the accelerator and gradually reduce
speed. The tire will need to be replaced before proceeding.
•If towing a trailer, stop driving as soon as safely and reasonably
possible. In this condition, it is potentially dangerous to operate a
vehicle/trailer combination.If possible, disconnect the trailer and
proceed as noted above. Do not continue to tow any trailer until proper
tire service or replacement has been performed.
•Do not touch a tire recently run-low or run-flat (it may be very hot).
Allow the tire to cool before handling.
DISTANCE—HOW FAR YOU CAN DRIVE
Factors affecting run-flat or low tire pressure operating distance include
vehicle speed, load, and maneuvering; the amount of inflation pressure
loss; the extent of any tire damage; and ambient temperature.
The tire may be marked on the sidewall with run-flat or low tire pressure
operating speed and/or distance limitations, which vary by tire design
and vehicle application (consult your vehicle owner ’s manual). By
international standard, RFT tires have a baseline limitation in run-flat
mode of the following:
Maximum Speed: 50 mph (80 km/h)
Maximum Distance: 50 miles (80 km)
NOTE:
•Maximum distance values are determined under controlled condi-
tions, which may vary in actual use.
•Your mileage capability may be less, or more, depending on your
specific operating conditions.
•If in doubt, do not exceed the 50 mile (80 km) limitation.
•Seek tire service as soon as possible to minimize tire damage.
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