CREATING AND MAINTAINING A LONG-TERM, COST-EFFECTIVE TIRE-MANAGEMENT PLAN.
By Mark S. Kuhar
Establishing a strategic tire-management plan is crucial for companies with large fleets of equipment. Each machine requires a unique tire replacement schedule, and managers who develop a tire buying and maintenance strategy are ultimately more productive than managers who wait until a problem occurs.
According to the experts at Titan Tire Corp., throughout the life span of a piece of equipment, tires need to be replaced more frequently than any other component, and as such, their efficient life cycle management offers arguably the greatest opportunity to control costs.
With a well-informed and well-defined tire maintenance and replacement strategy in place, a fleet manager can proactively manage these valuable equipment assets, while reducing the hassle and stress associated with unplanned downtime.
The first step in creating a successful plan is to establish a track record of tire performance.
Develop a tire performance record. “The first thing you want to do in developing a tire management plan is to establish a baseline of performance, both current and past,” said Johni Francis, global product manager for Titan Tire Corp. “Doing so will help identify problems and their potential causes.”
As a global product manager for Titan Tire Corp., Francis helps implement tire management programs for aggregate and mine sites all over the world. He recommends that fleet managers engage their local tire dealer to begin the process of identifying current and past trends in tire wear.
“Some of the most common tire problems are uneven wear, damage to the sidewall, separations in the tire, and damage to the beads or lining – each of which is a telltale sign that the tire maintenance regimen could be better managed,” said Francis.
He goes on to explain that incorrect inflation pressure is often the culprit behind the aforementioned signs of premature tire fatigue.
“Separations in the tire are generally a sign that it has been overloaded or underinflated,” said Francis. “Continuously running a tire that has insufficient air pressure to carry the load can generate enough heat to cause a breakdown between the materials and the adhesions.”
Similarly, he explains that running an overloaded or underinflated tire can cause excessive wear to the shoulders, diagonal breaks inside of the tire and increased deflection, which makes the tire more susceptible to cuts in the sidewall. On the other hand, an overinflated tire can lead to impact damage and excessive centerline tread wear.
“While faults in the tire maintenance regimen can result in shortened tire life, operator use can have an equally profound impact,” said Francis. “So, after establishing a baseline of tire performance, the next step in identifying problems is to have the dealer out to the jobsite for an operational assessment.”
Assess operational behaviors. There are a number of different operator tendencies that can negatively affect tire longevity, which is why Francis recommends that the tire dealer record everything from average haul distances, peak speeds and cycle times, to number of shifts, days worked, cycles completed and type of materials being moved. Doing so helps to forecast expected lifespan under ideal conditions, and thus, identify problems.
“No matter which type of machine we’re talking about, there are a few generalities we can make when talking about operator use and its affect on tires,” said Francis. “Things like rapid stops and starts and sharp turns can put unnecessary stress on the casing, leading to premature wear. Excessive speed generates heat, which can degrade the tire. Additionally, it’s important to remember that the heavier the load, the more drastic the impact to the tires will be with all three of these operator tendencies.”
For fleets including larger equipment, such as haul trucks, Francis stresses the importance of calculating the operators’ ton-mile-per-hour (TMPH) ratings, which utilizes a formula to calculate the heat a tire will generate based on the way it is being operated. TMPH is calculated as the average weight of the vehicle multiplied by the average speed of the vehicle.
“Haul truck tires come with a TMPH rating, and exceeding that rating will cause damage to the tire,” said Francis. “So, it’s very important for the dealer to conduct an operational assessment in order to determine if the fleet’s tires have a sufficient TMPH rating or if the operators are putting those tires through too much abuse.”
In addition to assessing past tire performance and operations, the third and final step in identifying problems and developing a tire management program is for the dealer to conduct a site assessment.
Evaluate job site conditions. The condition of the job site will not only help the dealer recommend the appropriate tire for the application, but also help identify any obstacles that are causing tire damage.
“Things like sharp curves and steep grades can affect load capacity. When an operator takes a sharp right turn, additional weight is shifted to the driver’s side tires. Similarly, going down a steep slope shifts the weight to the front tires, and going up a steep slope shifts the weight to the rear tires,” explained Francis. “Another thing fleet managers tend to forget is that mud adds weight to a vehicle. So, these are all things the fleet manager needs to be cognizant of, because they may necessitate adjusting tire inflation pressures and/or reducing the maximum allowable load.”
Maintaining a clean job site is also critical in reducing damage to tires, as Francis explains.
“Standing water is one of the primary ingredients needed to cut and puncture a tire, so it’s important to remove standing water whenever possible,” said Francis. “And of course, keeping the job site clear from any spillage of materials will undoubtedly help to extend tire life.”
In addition to identifying obstacles that could potentially threaten tire life, an assessment of the natural terrain will help determine if the fleet manager has the right type of tire for the job.
Establish a routine maintenance schedule. A submitted report with current tire conditions will outline any tires that need to be capped, repaired, matched, rotated or replaced. This information can provide the fleet manager with projected tire needs. In terms of regular maintenance, Francis stresses that monitoring inflation pressures is the most important task in prolonging tire life.
“Paying proper attention to inflation pressure can extend tire life by up to 30 percent,” said Francis. “So, I would recommend checking inflation pressures daily, before the machine has been started and is still cold.”
Francis goes on to say that problems with operator abuse can be diminished with the installation of pressure sensors.
“With today’s in-cab monitors, it’s getting easier for operators to spot problems before they escalate,” he explained. “If an operator realizes that a tire is even just 10 psi below where it should be, that should be cause for concern. Catching a problem early on could mean the difference between replacing a $40 valve and replacing the whole tire.”
Francis also stresses the importance of tire rotation – the strategy of which depends on the individual machine.
“For a three-axle haul truck, about 55 to 65 percent of gross vehicle weight is carried by the front tires when empty, so it’s important to rotate the fronts to the rear at about one-third of the tires’ expected life spans. When loaded, however, approximately one-third of the weight is distributed to each axle, so it’s also important to look at how operational and site conditions affect tire wear in order to make a rotation recommendation,” said Francis. “On a loader, you have to keep in mind that the front tires usually bear 65 percent of the load with a bucket attached. So, it’s really important to rotate front to rear in order to give the front tires a rest for the remaining 50 percent of their projected life.”
Lastly, Francis stresses the importance of knowing when to replace versus when to repair.
“A good rule of thumb is to consult your tire dealer on all repairs. Tire punctures aren’t always straight, so pressing a plug straight into the tire could cause additional damage,” said Francis. “If a tire is running low on tread, but is still holding air and is structurally sound, it may be a good candidate for retreading. The important thing to remember, however, is to pull that tire off with about 15 percent of the tread remaining. If it goes much further than that, and any of the under-tread compound is exposed, it’s too late.”
Implement the program. “Ultimately, successful implementation of a tire management program takes buy-in from both the fleet manager and the operators,” said Francis. “It’s important for the fleet manager to train the operators to use the equipment within its limits and to report any changes in inflation pressure or job site conditions that could lead to potential problems.”
Francis also believes ongoing consultation from the tire dealer is essential to a successful long-term program.
“It’s important to consult with the tire dealer as changes occur that could potentially affect the tire management program,” said Francis. “As an operation expands, haul distances, speeds, loads, site conditions, cycle times and equipment configurations can all change. Each of these factors necessitates a change to the tire management program, and as such, the fleet manager should work closely with his or her tire dealer for recommendations whenever major changes occur.”
Information for this article courtesy of Titan Tire Corp.