GUEST EDITORIAL
According to the Technology and Maintenance
The most critical
factor in tire maintenance
is proper inflation.
58 Fleet Maintenance | July 2018
Council’s Tire and Wheel Study
Group Information Report: 2010-2 Tire Pressure
Monitoring and Infl ation Maintenance, tires are
the second largest investment for a fl eet.
Because of this, it is critical that tires are properly
maintained and managed. Th e following
is a compilation of best practices for tire maintenance,
but by no means are fl eets limited to
these best practices.
Tire pressure systems can provide fl eets
a means to more closely monitor the performance
and status of tires on their vehicles.
A big challenge for fl eets is to determine
which type of tire pressure system will provide
the best return on investment (ROI) or total cost
of ownership (TCO) for their individual needs.
Options available
When it comes to tire pressure systems, SAE and
NACFE defi ne the following three system choices:
• Monitoring – Commonly referred to tire
pressure monitoring systems (TPMS), monitoring
systems record and
communicate past and
current tire conditions.
Th is system can provide
real-time information, but
only provides notifi cation
of an issue. Th e driver or
fl eet is required to take
corrective action.
• Maintenance – In addition to monitoring
capabilities, maintenance systems can add or
release air pressure automatically when needed
to maintain a preset level on each tire. Th ese
systems are commonly referred to as automatic
tire infl ation systems (ATIS).
• Management – Tire management systems can
adaptively alter air pressure through programming
dependent upon load, speed and other
variables. Th ese types of systems are commonly
referred to as central tire infl ation systems (CTIS).
Th ere are pressure systems available for
both tractors and trailers. It is important to
note there are diff erences in these systems
dependent on the type of tire.
Preventive maintenance
practices
Th ere are several preventive maintenance
practices that are crucial to maintaining tire
life. Th e most critical factor is proper infl ation.
Step one is to measure every vehicle tire for
proper infl ation, correcting underinfl ated or
overinfl ated tires. Check tires when they’re
cold, or at least three hours aft er use.
Typically, tires should maintain 85 to 100
psig, with variances dependent on application,
tire construction and manufacturer’s
guidelines. Many fl eets like to run at one tire
pressure setting in all tire locations, as this is
the easiest to communicate consistently and
for drivers or technicians to remember.
An underinfl ated tire has a larger ground
contact footprint, which increases contact with
the road and creates higher internal stresses
(heat) in the tire casing. Th e larger footprint
increases rolling resistance, thus requiring
more energy from the vehicle to rotate the tire.
Meanwhile, an overinfl ated tire decreases
fuel economy and overall tire life, leading to
an increase in operating costs. Over-infl ation
can increase the potential for catastrophic tire
failure or other issues.
It is important not to overload the tires. Th e
maximum load is dependent on the application.
Fleets can avoid excessive heat buildup,
which can lead to tire deterioration, damage
or failure, by following the tire manufacturer’s
recommended allowable load for an application.
Fleets can take a proactive approach to monitor
the load using any of the pressure systems
mentioned earlier.
Pre-trip inspection guidelines
To increase safety and prevent downtime, a
pre-trip inspection is recommended for every
vehicle leaving the facility each day. Below are
a list of steps to follow for this inspection.
Step 1 - Check tire for proper infl ation. If a
tire is 20 percent below the recommended psi,
it should be checked for damage and repaired
or replaced before beginning service.
Dual tires should be within 10 psi of one
another. Maintaining proper infl ation pressure
in duals can minimize the damage caused by
mismatched diameter, which will prolong tread
and casing life.
Th e tire infl ation system installed on the vehicle
will determine the method for inspection.
Step 2 - Visually inspect tires for damage
or defects, checking for wear, bulges, cracks,
cuts or elements that have penetrated the tire.
When a tire maintenance system is present,
visually inspect the system hoses in addition
to the tire.
Step 3 - Check valve caps to ensure they are
present and properly secured.
Step 4 - Check for tread wear by measuring
the tread depth. It’s important to know the tire
tread depth when new, and then take subsequent
tread measurements at the same spot
on the tread, close to the center of the groove.
Step 5 - Check wheel for rust, dents and any
deviations.
Step 6 - Inspect the vehicle’s suspension.
• Check the suspension to be sure it is fully
operational, ensuring it is visually free of
any obvious signs of failure in any major
component.
• Visually inspect all suspension component
fasteners.
• Visually inspect air springs for suffi cient
and equal pressure, and check to see that the
suspension is set at proper ride height. Refer
to the suspension manufacturer’s maintenance
manual instructions.
• Check that the suspension ride height is within
+/- 1/4” of the suspension manufacturer’s
recommended height. An improperly set ride
height could result in suspension component
damage and/or poor vehicle ride performance.
Refer to the suspension manufacturer’s maintenance
manual instructions.
• Inspect nuts and bolts at the pivot connections,
transverse beam connections and axle connections
to assure they are properly torqued.
• Check the air spring and shock absorber
fasteners and all other nuts and bolts for proper
torque, re-torquing as necessary.
• With vehicle on level surface and air pressure
in excess of 70 psig, all air springs should be of
suffi cient and equal fi rmness. Note that height
control valves control all air springs. Check
all fi ttings for air leaks by applying a soapy
water solution and checking for bubbles at all
air connections and fi ttings.
• Check all other suspension components for
any sign of damage, looseness, wear or cracks,
replacing any damaged parts to prevent equipment
breakdown. It is important to note only
lubricants recommended by your suspension
manufacturer should be used. Refer to your
suspension manufacturer’s maintenance
manual instructions.
Conclusion
Comprehensive tire maintenance and management
is critical to maximizing a fl eet vehicle’s
uptime. Th ere are a number of tire pressure
systems available to spec on these vehicles in
order to optimize tire monitoring and management.
Be sure to complete thorough research
to fi nd what’s best for the fl eet.
Tire pressure system
options for fl eets
Tire pressure systems can
provide fl eets a means to more
closely monitor, maintain and
manage the performance and
status of tires on the vehicle.
By Bill Hicks
MANAGER OF PRODUCT PLANNING AMERICAS,
SAF-HOLLAND
SAF-Holland specializes in trailer axle and brake suspension
systems, fifth wheels, couplings, kingpins, landing
gear, and suspensions for trucks, buses and tractors.
Hicks has more than 30 years of experience at SAFHolland,
holding various positions in engineering, service
and product planning. Hicks is the in-house subject matter
expert on ATIS as well as other inflation options.