Winnebago Towables User Manual page 22

SECTION 3 –
RECOMMENDATIONS
Understanding Tire Pressure and Load
Limits
Tire inflation pressure is the level of air in the
tire that provides it with load-carrying capacity
and affects the overall performance of the
vehicle. The tire inflation pressure is a number
that indicates the amount of air pressure–
measured in pounds per square inch (psi)–a tire
requires to be properly inflated. (You will also
find this number on the vehicle information
placard expressed in kilopascals (kPa), which is
the metric measure used internationally.)
Vehicle manufacturers determine this number
based on the vehicle's design load limit, that is,
the greatest amount of weight a vehicle can safely
carry and the vehicle's tire size. The proper tire
pressure for your vehicle is referred to as the
"recommended cold inflation pressure." (As you
will read below, it is difficult to obtain the
recommended tire pressure if your tires are not
cold.)
Because tires are designed to be used on more
than one type of vehicle, tire manufacturers list
the "maximum permissible inflation pressure" on
the tire sidewall. This number is the greatest
amount of air pressure that should ever be put in
the tire under normal driving conditions.
Checking Tire Pressure
It is important to check your vehicle's tire
pressure at least once a month for the following
reasons:
• Most tires may naturally lose air over time.
• Tires can lose air suddenly if you drive over a
pothole or other object or if you strike the curb
when parking.
• With radial tires, it is usually not possible to
determine under inflation by visual
inspection.
For convenience, purchase a tire pressure
gauge to keep in your vehicle. Gauges can be
purchased at tire dealerships, auto supply stores,
and other retail outlets.
The recommended tire inflation pressure that
vehicle manufacturers provide reflects the proper
psi when a tire is cold. The term cold does not
3-8
relate to the outside temperature. Rather, a cold
tire is one that has not been driven on for the last
three hours. When you drive, your tires get
warmer, causing the air pressure within them to
increase. Therefore, to get an accurate tire
pressure reading, you must measure tire pressure
when the tires are cold or compensate for the
extra pressure in warm tires.
Steps for Maintaining Proper Tire
Pressure
Step 1: Locate the recommended tire pressure
on the vehicle's tire information placard, certifi-
cation label, or in the owner's manual.
Step 2: Record the tire pressure of all tires.
Step 3: If the tire pressure is too high in any of
the tires, slowly release air by gently pressing on
the tire valve stem with the edge of your tire
gauge until you get to the correct tire pressure.
Step 4: If the tire pressure is too low, note the
difference between the measured tire pressure
and the correct tire pressure. These "missing"
pounds of pressure are what you will need to
add.
Step 5: At a service station, add the missing
pounds of air pressure to each tire that is under-
inflated.
Step 6: Check all the tires to make sure they
have the same air pressure (except in cases in
which the front and rear tires are supposed to
have different amounts of pressure).
If you have been driving your vehicle and
think that a tire is underinflated, fill it to the
recommended cold inflation pressure indicated
on your vehicle's tire information placard or
certification label. While your tire may still be
slightly underinflated due to the extra pounds of
pressure in the warm tire, it is safer to drive with
air pressure that is slightly lower than the vehicle
manufacturer's recommended cold inflation
pressure than to drive with a significantly