JLG Triple-L Operator Manual - Manual (Page 63)

SECTION 4 - SERVICE AND MAINTENANCE
3121224 – Triple-L-Trailer – 4-23
Safety First – Basic Tire Maintenance
Properly maintained tires improve the steering, stopping,
traction, and load-carrying capability of your vehicle.
Under-inflated tires and overloaded vehicles are a major
cause of tire failure. Therefore, as mentioned above, to
avoid flat tires and other types of tire failure, you should
maintain proper tire pressure, observe tire and vehicle
load limits, avoid road hazards, and regularly inspect your
tires.
Finding Your Vehicle's Recommended Tire Pressure
And Load Limits
Tire information placards and vehicle certification labels
contain information on tires and load limits. These labels
indicate the vehicle manufacturer's information including:
Recommended tire size Recommended tire inflation pres-
sure Vehicle capacity weight (VCW–the maximum occu-
pant and cargo weight a vehicle is designed to carry)
Front and rear gross axle weight ratings (GAWR– the max-
imum weight the axle systems are designed to carry).
Both placards and certification labels are permanently
attached to the trailer near the left front.
Understanding Tire Pressure And Load Limits
Tire inflation pressure is the level of air in the tire that pro-
vides 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– mea-
sured 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.)
Manufacturers of passenger vehicles and light trucks
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 "recom-
mended 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 per-
missible inflation pressure" on the tire sidewall. This num-
ber 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 dealer-
ships, auto supply stores, and other retail outlets.
The recommended tire inflation pressure that vehicle man-
ufacturers provide reflects the proper psi when a tire is
cold. The term cold does not relate to the outside temper-
ature. Rather, a cold tire is one that has not been driven on
for at least 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, certification 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 pressure.
• Step 4: If the tire pressure is too low, note the differ-
ence between the measured tire pressure and the cor-
rect 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 under-inflated, fill it to the recommended cold inflation
pressure indicated on your vehicle's tire information plac-
ard or certification label. While your tire may still be slightly
under-inflated 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 recom-
mended cold inflation pressure than to drive with a signifi-
cantly under-inflated tire. Since this is a temporary fix,
don't forget to recheck and adjust the tire's pressure when
you can obtain a cold reading.
Tire Size
To maintain tire safety, purchase new tires that are the
same size as the vehicle's original tires or another size rec-
ommended by the manufacturer. Look at the tire informa-
tion placard, the owner's manual, or the sidewall of the tire
you are replacing to find this information. If you have any
doubt about the correct size to choose, consult with the
tire dealer.