March 2014, TruckingInfo.com - Department
Still waiting for the million-mile tire? Don’t hold your breath, but we’ll probably see such a tire in our lifetime. For now, you’ll have to settle for half a million miles.
Even the best tires money can buy will profit from a little help. Basic maintenance can prolong tire life, sometimes dramatically.
If it’s hard for you to see the words “half a million miles” and “tires” in the same sentence, maybe you’re not doing everything possible to preserve or enhance the life of your tires.
Ron Szapacs, former maintenance specialist for power vehicles at Air Products & Chemicals Inc., now retired, told me several years ago that he had several set of tires, Michelin X Ones to be precise, that were at or over 400,000 miles when they were taken off the power units and run out on trailers. He told me they still had at least 20% of the tread left, but he wasn’t tracking trailer tire mileage so he couldn’t say how far they went.
I remember him saying they were wearing very well, with no edge wear – which was a common complaint with wide-single tires – and nice even wear across the tread face. The secret, he told me, was regular pressure checks and mechanical inspections on the trucks.
“I took away as many threats to the tires that I could,” he said. “I couldn’t really control road hazards or driver treatment of the tires, but I tried to eliminate as many of the mechanical problems as possible.”
Four hundred thousand miles from a set of drive tires is a pretty ambitious goal, and one not even remotely possible in many applications, but for the conscientious and maintenance-focused long-haul fleet, it’s clearly achievable.
Here are three must-do rules of tire maintenance that will maximize tire life and help you squeeze every last penny from your tire investment.
Of course spec’ing the right tire for the applications is the best way to start. Why use a lug tire where a rib tire will work or a tough regional tire in a long-haul application? More and more, tires are becoming task-specific.
Starting with the right tire will ensure a better outcome.
Give some thought
to your inflation
pressure. Using 100 psi arbitrarily may not be the best pressure for your application. It certainly isn’t enough for a steer tire.
1. Keep them properly inflated
Technology is lessening the burden of maintaining proper inflation pressure, whatever you deem that to be. Tire manufacturers prescribe minimum inflation pressures in their Load & Inflation tables, and they are lower than you might expect.
The standard recommendation is to inflate to the maximum load the tires will carry. On a legally loaded tandem axle, that’s 4,250 pounds per tire, or by the tables, about 75 psi to 80 psi, depending on the tire size and type. Some claim inflating such tires to 100 psi or more as a margin for error might compromise tread life.
Herman Miller, president of HJM Fleet Maintenance, runs his tires close to the L&I table minimums – 110 psi in steer tires, 75 psi in drive tires and 80 psi in trailer tires.
He says the lower pressure yields a more even contact patch and makes the tires more resistant to impact damage while giving up practically nothing in fuel savings.
“I believe that there may be some small increase in fuel economy, but I never could quantify it,” Miller says, adding, “There are far more compelling reasons to run lower pressures than higher if you have a solid tire maintenance program.”
Miller’s fleet runs light loads, mostly general merchandise for retail chains. He seldom goes over 70,000 pounds GVW. The key, Miller says, is the ability of the slightly softer tire to flex the way it was designed to.
“We had almost no impact damage in all those years, and we saw none of the irregular wear that a lot of fleets complain about,” notes Miller. “Those problems come from tires that are too hard to function the way they are designed to function – that is, having enough give in the casing to absorb impacts like pot holes and road debris, and having the optimum footprint or contact patch.”
Whatever pressure you decide is optimum for your operation, tire pressure monitoring systems and automatic inflation systems let you get closer to optimum pressure with less risk of dropping below the minimum. Pay strict attention to matching pressure between the tires in a dual assembly as well. If one is much lower than the other, you’ll kill both tires.
Retreading can triple the mileage you get from your initial tire investment, at about half the cost over its total life.
2. Minimize mechanical threats
The truck itself could be your tires’ worst enemy. From bad alignment to worn shock absorbers or even loose wheel bearings, the list of suspects is a long one. The tires, of course, suffer the consequences of a bad situation somewhere else on the truck. In fact they may be the best tool you may have for detecting and eventually resolving those problems.
Tires are literally the canary in the coal mine. Every possible mechanical irregularity leaves a signature scar on a tire – feathered wear on a mal-aligned drive tire, for example. In fact, it was exactly that kind of tire wear that got Bill Bliem, the senior vice president of Fleet Services at NFI Transportation in Vineland, N.J., and one of HDT’s 2014 Truck Fleet Innovators, interested in alignment.
“I had just started with NFI and I was doing a yard check with one of the maintenance supervisors,” he recalls. “I had just passed my hand over a few drive tires and it struck me that most of them were feathered. I asked the supervisor if NFI was aligning trucks, and he said no.”
Bliem started doing laser alignments and found some drive axles were as much as half an inch out of parallel.
“I can’t tell you exactly how much money alignments have saved us, but I can say as much as tire prices have risen in the past five years, our tire costs haven’t changed,” he says. “We built a few of our own laser alignment jigs for a few hundred dollars several years ago, and today, I guess I spend about $100 a year per truck checking and keeping the trucks aligned. That’s about $10 per tire.”
Balance is another one of those tire maintenance tough sells. With new tires, balance is hardly ever an issue anymore, as long as the tire is mounted concentrically (do you ever check that thin little ring on the sidewall just beside the wheel flange?) and the dots and dimples on the tire and wheel line up. But what about hubs and brake drums that might be out of balance, or worn hub pilots that could cause an out of round condition with the wheel/tire? Or how about some other condition that unevenly removes rubber from the tread?
Sure, the tire was properly balanced they day you installed it, but in as little as a month, it could be out of balance.
Dynamic balancing compounds such as Equal or Magnum, or balancing rings such as Centramatic, can keep a tire/wheel assembly balanced for the life of the tire, even if irregular wear is present.
“Equal moves freely inside the tire and seeks low spots in the tread and balances the weight of the missing rubber,” says Bob Fogal Jr., president and CEO of International Marketing Inc. (makers of Equal). “The tire remains perfectly balanced due to the distribution of the compound in the tire as it rotates.”
Unlike fixed weights that have to be removed, then reinstalled when the wheel is rebalanced, balancing powders can stay in the tire, and they will go to work in the first mile of rotation.
“Balancing isn’t something a fleet will do every time a tire is changed or a flat is repaired,” says Robert Coolidge, president of Centramatic. “Once you have invested in a set of balancing rings, they can remain at a wheel position, balancing any tire/wheel assembly that is mounted there.”
There’s no better way to lower your lifetime tire cost per mile than retreading. Our sister publication, Modern Tire Dealer, just released some statistics about retreads, and they found that the average price of a retread is about $140 less than the average price of a new replacement tire.
That’s a pretty compelling reason to consider retreading, but when you factor in as many as two retreads on a single casing, you’re tripling the value of that casing but effectively getting three times the mileage from it.
“An effective retreading program for commercial truck tires is key to achieving the lowest total tire life cycle cost,” says Bill Sweatman, president and CEO of Marangoni Tread North America. “Selecting a quality tire that is proven to be retreadable and maintaining it properly during its first life provides opportunity to extend the life of the casing through multiple retread lives.”
In most cases, given due care and consideration, a retread is no more susceptible to failure than a new tire. Neglected, any tire will eventually suffer from underinflation and will eventually explode, leaving your truck stranded at roadside.
Sweatman says it’s important to commit to selecting a retreading system that makes retread decisions for you and your tires based on optimizing total cost of ownership.
“Price will always be a consideration,” he says. But modern retread technologies, from initial inspection through final inspection and proper tread selection, can result in performance after retreading that is superior to that of the original new tire life, Sweatman says.
If your fleet is diligent in these three tire maintenance disciplines, chances are you’re getting your money’s worth from your tires. If you’re lagging somewhere, that may be all that’s standing between you a half-million-mile tire – maybe more if you count retreads.