Page 156 of 260
NITTO TIRE
154
TIRE PRESSURE BASICS
The combined effect of losing 1 psi per month over several months
along with a 1 psi decrease for every 10°F temperature drop could
add up to a severe “run low” condition; consequently, it is important
to check your tires’ inflation pressure at least once per month. Inflation
pressure enables a tire to support its load; therefore, proper inflation
is critical.
HOW TO DETERMINE PROPER TIRE INFLATION PRESSURE
It is impossible to determine whether tires are properly inflated
just by looking at them.
Page 158 of 260
NITTO TIRE
156
It is important to check your tires using an accurate tire
pressure gauge, which can be purchased at your tire dealer
or auto supply store.
Underinflation can overload tires. Check the inflation pressure every
month, including for the spare tire, to make sure it’s up to specification.
Check it again before long trips or when carrying extra weight.
Look for the manufacturer’s recommended inflation pressure listed
on the Tire Information Placard usually located on your vehicle’s door
edge, door post, glove box, or inside the trunk lid.
Page 159 of 260

NITTO TIRE
157
USING A TIRE PRESSURE GAUGE
For accuracy, check your inflation pressure with a tire pressure gauge
when tires are cold (for example, after being parked overnight). Driving
heats up tires and causes an inaccurate pressure reading.
To check inflation pressure with a tire pressure gauge:1.
Remove the tire valve cap.
2.
Place the end of the tire pressure gauge over the valve.
3.
Press the tire pressure gauge straight and firmly and take
a reading.
4.
If needed, inflate and recheck the pressure with the tire
pressure gauge.
5.
Replace the valve cap.
RECOMMENDATIONS FOR SAFE TIRE INFLATION •
If you must inflate your tires when they are hot, add 4 pounds per
square inch (4 psi) (28 kPa) above the recommended inflation
pressure specification. Recheck the inflation pressure when the
tires are cold and adjust to the recommended inflation pressure
shown on the vehicle’s Tire Information Placard.
•
Never release air or nitrogen from a hot tire in order to reach
the recommended cold tire pressure. Normal driving causes
tires to run hotter and inflation pressure to increase. If you
release pressure when your tires are hot, you may dangerously
underinflate your tires. If your tires lose more than 1 pound
per square inch (1 psi) per month, the tire, the valve, or the
wheel may be damaged. Consult your authorized Nitto dealer for
an inspection.
Page 160 of 260
NITTO TIRE
158
• Over-inflation can cause the tire to be more susceptible to
impact damage.
•
Over-inflation or underinflation may adversely affect vehicle
handling.
•
Remember to check your spare tire. Consult your vehicle Owner’s
Manual for the correct inflation pressure and use of a “temporary
use” spare tire. The inflation pressure specified for a spare tire is
typically different from that specified for your regular tires.
•
Use valve caps to keep valve cores clean and clear of debris and
to help guard against air leakage.
VEHICLES EQUIPPED WITH TIRE PRESSURE MONITORING
SYSTEMS (TPMS)
Even if your vehicle is equipped with a tire pressure monitoring
system, you should check your tire pressure at least once per month
when the tires are cold (for example, after being parked overnight).
Tire pressure warning systems are not a substitute for regular tire
pressure maintenance.
Page 161 of 260

NITTO TIRE
159
IDENTIFYING DAMAGED TIRES•
If your tire strikes a road hazard at any speed, internal tire damage
could result, which may lead to sudden tire failure and loss of
vehicle control. Tire failure may even occur miles after the initial
impact. Impact damage from such hazards may not be visible on
the outside of the tire. Have your Nitto dealer dismount the tire and
inspect it for damage. A tire may not have visible signs of damage
on the tire surface or the interior.
•
If the impact was sufficient to bend the wheel flange, internal
tire damage may have occurred, compromising the safety and
integrity of the tire. Such impact damage may result in a sudden
tire failure many weeks or months later. Tire replacement is highly
recommended as a safety precaution.
•
Indications of impact damage include, but are not limited to, a
bubble or a blister on the outside of the tire.
•
Have your dealer inspect your tires if you see anything unusual
or if cuts, cracks, splitting, or bruises in the tread and sidewall
areas are visible. Bumps or bulges may indicate a serious and
dangerous separation within the tire body. Have your tire inspected
by a qualified tire service person. It may be necessary to have the
tire removed from the wheel for a complete inspection.
•
Inspect your tires for adequate tread depth. When the tire is worn
to the built-in indicators at 2/32” (1.6 mm) or less tread groove
depth, the tire is worn out and must be replaced. Never drive on
tires to the point that the tire cord or the fabric is exposed.
•
Inspect your tires for uneven wear. Wear on one side of the tread
or flat spots in the tread may indicate alignment or other problems
with the tires or the vehicle. Consult your authorized Nitto dealer.
Page 162 of 260

NITTO TIRE
160
IDENTIFYING DAMAGED WHEELS
Periodically check to see if any of the following symptoms exist, in
which case the wheel must be replaced:•
If the flange is bent.
•
If welds or rivets are leaking.
•
If the stud holes are elongated and not round. (Improper lug nut
tightening could cause this.)
•
If there are cracks in the wheel.
WORN OUT TIRES
Tires must be replaced when tread is worn to 2/32” (1.6 mm).
Treadwear indicators on Nitto tire treads show the 2/32” depth (1.6
mm). Most states require that tires be replaced when the tread depth is\
worn to 2/32” (1.6 mm). Tires may lose sufficient wet and snow traction
before reaching 2/32” (1.6 mm) of wear. Many wet weather accidents
result from skidding on worn out tires.
Excessively worn tires are more susceptible to penetrations. Consider
replacing your tires earlier if you drive in snow or wet conditions.
Any retail tire dealer will be glad to measure your tire’s tread depth for
you. Nitto recommends that tires be replaced in matched sets of four.
TIRE REPAIRS
If any tire has sustained a puncture, have the tire dismounted and
inspected internally by an authorized Nitto dealer for possible damage
that may have occurred. Only specially trained personnel using the
proper tools and procedures should repair tires.
Page 163 of 260
NITTO TIRE
161
• Never repair a tire with 2/32” (1.6 mm) or less tread remaining.
At this tread depth, the tire is worn out and must be replaced.
•
Never repair a tire with a puncture larger than ¼” (6.4 mm)
in diameter. Such tires cannot be properly repaired and must
be replaced.
•
Repairs of all tires (radial and non-radial) must be of the plug and
inside patch type. Using plugs alone on any type of tire is not a
safe repair.
•
Do not use a rope type plug for repair. A tire must
be removed from the wheel and inspected for
interior damage. Any tire repair done without
removing the tire from the wheel is improper
and unsafe.
•
Never repair a tire with a puncture or other
damage outside the tread area. Do not repair
sidewall damage. Such tires cannot be properly
repaired and must be replaced.
Page 164 of 260
NITTO TIRE
162
Nitto speed-rated passenger car tires may be repaired and
returned to service under the following conditions:•
Proper repair materials and procedures have been used.
•
The damage or puncture is not larger than 1/4” (6.4 mm)
in diameter.
•
The repair will be the first repair performed on that tire. (Only
one repair per tire is permitted in order to maintain a limited
speed rating.)
•
The tire must have more than 2/32” (1.6 mm) of tread remaining.
Nitto speed-rated passenger tires that have been properly
repaired qualify for reduced speed ratings as follows:
The maximum speed of a vehicle is limited by the lowest-speedrated
tire on the car.
PROPER SELECTION OF TIRES
When tires need to be replaced, don’t guess what tire is right for your
vehicle. First look at the vehicle Owner’s Manual or the Tire Information
Placard. They tell you the size of the tires that were on the vehicle as
original equipment.