tire basics - Engage360Training.com

TIRE BASICS
SAFETY WARNINGS
Truck tires are built to provide many thousands of miles of reliable performance. But
they must be properly maintained in order to deliver the best service possible. The
life of a truck tire is dependent upon many factors: its storage, rotation and service
conditions – like carrying loads, driving speed, its inflation pressure, any road hazard
injuries and more. And because service conditions can vary widely, it can be difficult to
accurately predict the standard life of a truck tire.
The life of a truck tire is dependent on:
• Storage
• Stowing
• Rotation
And service conditions • Carrying Loads
• Driving Speed
• Inflation Pressure
• Road Hazard Injuries
No matter how well a tire is constructed, a number of factors can lead to reduced service life and
even tire failure:
• Impact damage
• Punctures
• Improper inflation
• Improper maintenance
• And other service-related factors.
That’s why it’s crucial that all drivers, fleet service personnel -- and even you – should routinely
inspect a vehicle’s tires for safety concerns such as:
• Bulges
• Cuts
• Snags
• Rapid and irregular treadwear
• Improper inflation
• And tread separation
Regulations and procedural guidelines for the safe servicing of tires and rims have been prepared by
the US Department of Labor and Occupational Health Administration (OSHA). Be sure to review them
all. Failure to comply with safety warnings can result in serious injury or death.
TIRE BASICS
SAFETY WARNINGS
TIRE BASICS
SAFETY WARNINGS
TIRE BASICS
Also, be sure to review all of the important safety warnings in the warranty PDF in this module.
(Tire Warranty PDF)
Inflation:
Maintaining proper inflation pressure is critical.
All tires – no matter who manufactures them – lose air pressure very slowly with the passage of time.
In addition, inflation pressures increase or decrease in direct relationship to temperature changes.
Tire pressures should always be checked with a temperature gauge when the tires are cold, or have
been out of service for at least three hours.
Never reduce inflation pressures when tires are hot, and do not exceed the pressure limit molded into
the sidewall when tires are cold.
TIRE BASICS
SAFETY WARNINGS
Overinflation:
On an overinflated tire, the center of the tread bears the brunt of the vehicle load. If this is the case,
the inside tread of the tires wears out faster than the outside edges.
To prevent overinflation, be sure to check tires when they’re cold.
Underinflation:
Underinflation reduces tread life through increased treadwear on the tire’s shoulders. This generates
excessive heat, which reduces tread life and casing durability -- and can ultimately lead to tire and
casing failure. Underinflation also reduces fuel economy by increasing rolling resistance.
Sidewall Zipper Failure:
Sidewall zipper failure occurs when the tire sidewall explodes and they are named for the zipper-like
appearance of the destroyed tire’s sidewall. This type of tire failure is typically associated with the
inflation process and poses the risk of injury and possibly death to the tire inflator and any bystanders.
It is not uncommon for persons nearby a zipper failure explosion to experience hearing loss.
The Rubber Manufacturer’s Association offers safety bulletins and warning posters detailing how to
service a tire that may be a potential zipper failure risk.
Load Capacity of Replacement Tires
Replacement tires must have a load carrying capacity that is rated for the load experienced by
each wheel position. This is best determined by weighing a fully loaded single unit truck, or tractor
and trailer, and comparing the loaded axle weights to the sum of each tire’s load carrying capacity
mounted on the axle.
WARNING! Installers carry a significant risk of liability if they fit replacement tires
with lower load carrying capacity than is required to fully support the expected load,
or fail to adjust the vehicle air pressure to achieve the necessary tire load capacity.
Even proper size replacement tires will not have enough load capacity if the inflation is set incorrectly,
or if it is set too low. If undersized and underinflated, tires are applied to any vehicle, they are subject
to sudden failure due to fatigue -- and may result in loss of vehicle control, and the risk of serious
injury.
To select the proper load and inflation table for a tire or application, find the tire size in the Product
Data Book, then match your tire’s size and load markings to the table with the same sidewall
markings.
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