Keeping proper inflation is the easiest, highest-saving maintenance task you can perform.
This is a condensed chapter from the Overdrive 2008 Partners in Business manual for owner-operators. The next Partners in Business seminar will be held 2-4 p.m. Aug. 22 at the Great American Trucking Show in Dallas. To order a manual, call (800) 633-5953, Ext. 1301. Visit www.PIBlive.com for more excerpts and information. The seminars and the manual are brought to you by Overdrive, ATBS and Castrol.
You don’t buy tires nearly as often as fuel, but because tires are your second biggest variable cost, adopting cost-cutting tire practices really pays. The potential to save starts with the purchase process and doesn’t end until you’ve decided whether to get a recap of a worn tire.
Here are seven tips to making your tire purchases and maintenance pay off.
SPEC FOR YOUR APPLICATION. If you’re spec’ing a new truck, you can pick any tire size suitable to your application. A new truck’s drivetrain and engine controls are set according to the spec’d tire size. Replacement tires, however, may require drivetrain and engine adjustments. Rather than last longer, tires with deeper tread might wear faster, burn more fuel and make driving harder if they’re wrongly applied.
Many owner-operators now pick tires based on fuel economy. In some cases, tire makers have combined characteristics and made multi-application tires that are both durable and fuel-efficient.
SHOP FOR THE BEST VALUE. Once you know the tire type best suited to your application, judge the tires’ value: getting the most for your money, whether you spend a little or a lot.
It’s tempting for an owner-operator to shop primarily by sticker price, but cost per mile and potential for retreading are more important considerations. Making an informed choice means keeping written and dated records of purchase, fuel mileage and tread depth, then comparing records between models you’ve used.
Warranty is another factor in value. Most standard new-tire and retread warranties are about the same: coverage limited to normal-use defects in workmanship, product and material.
USE RETREADS. Premium tires cost between $300 and $600 new, whereas retreads average about $200. Retread casings are tested via road use and by laser scanning that detects virtually any flaw. The bonds that secure the new tread meld the tire’s layers together as one, making a well-done retread as reliable as the original tire.
Premium new tire makers design casings for retread use. Theoretically, undamaged casings can be repeatedly retreaded, although the tire maker’s casing warranty might run out at, say, 750,000 miles or after three retreadings.
USE WIDE SINGLES. Wide singles weigh less and save fuel. They also cost less than the two tires they’re designed to replace, although you have to buy new rims to get in the game. Wide singles are retreadable, too.
A common complaint about wide singles is that finding replacements while on the road can be difficult. Another is that whereas a flat dual allows you to “limp” to the next service site, a flat in a wide single immobilizes the truck, which means losses from downtime and road service. But an automatic tire inflation system can address most instances of that problem by keeping tires inflated to proper pressure.
PERFORM ROUTINE MAINTENANCE. Checking wheel alignment periodically can pay big dividends. Whenever you start seeing a heavy spot or a flat spot, the tire has ceased to be centered on the hub, and it’s beading out of round. The plungers inside shock absorbers create friction, and friction creates heat, so if the shock – not the outer dust barrel covering the top half of the shock – is hot to the touch after driving, it’s working. If it’s cool to the touch, it’s not working and should be replaced.
Also, make sure the bushings at the top and bottom of the shocks are inspected and replaced whenever worn. If you can grab the shock absorber and rattle it, the bushings have pounded themselves out, and the shock isn’t working as designed.
MAINTAIN PROPER INFLATION. Improper inflation is by far the most common reason tires fail or wear out prematurely. It also wastes fuel and weakens performance.
Manufacturers design big-truck tires for a specific pressure, usually clearly specified on the sidewall. For each pound of air pressure a tire loses, its temperature rises about 2 degrees. If the pressure’s too low, the sidewalls overflex, overheat and eventually come apart. That’s when the tread comes off.
A tire underinflated by 10 percent, about 10 psi, will rapidly experience about 10 percent to 15 percent tread loss. A tire underinflated by 20 percent is considered a flat. It should be dismounted and inspected for damage inside and out.
Don’t overinflate, either, assuming it’s an easy way to avoid unnecessary tire costs. An overinflated tire suffers rapid and irregular wear and is more susceptible to damage from running over debris and scrubbing curbs.
EMPLOY GOOD DRIVING HABITS. Much of what affects a tire’s longevity depends on what’s done with the steering wheel, brake and accelerator. Speeding, hard braking, curbing and tight turns cause tires to wear faster or even develop irregular wear.
If you notice unusual shimmying or repetitive bumps, inspect your tires. Even absent rough driving, look for irregular tread wear in your daily inspections.