Casings deserve a place in tire-cost management
Tire management deserves a closer look, particularly since the relative life span of truck tires continues to increase for both the original tread and the retread. In fact, thinking of tires as having these two distinctly different life stages can be helpful in making decisions about new-tire brands, retreads, maintenance practices, trade cycles, and even tire disposal.
Critical elements of new-tire performance have been thoroughly researched, as well as the importance of choosing a retread provider wisely. But how to determine which tire casings are best for you has received far less attention.
The importance of casings becomes more obvious when we consider that most over-the-road trucking operations have at least as many retreaded casings on the ground as they do new tires. In 1999, approximately 15.2-million new replacement tires and 19.2-million retreads were purchased in North America.
With this heavy mix of retread rolling stock, we should really be thinking about tire casings as assets. As one senior fleet manager put it, his tire management goal is no different than that for other components: "To extend asset (tire) life while delivering efficient performance consistent with controlled maintenance expenses, minimized downtime, and enhanced safety."
Efficient performance is an important element because keeping a tire casing in service longer simply postpones the necessity of replacing it through a new tire purchase.
Since truck tires derive their total rolling-resistance signatures from a combination of tread and casing characteristics, it's important to do a separate evaluation of casings - processed with identical retread materials - when you're comparing tires for fuel efficiency.
Another important consideration is casing durability, which has a direct impact on maintenance expenses. Are the casings easy to repair? Are special procedures or materials required? How large an injury is repairable? How compatible are the casings with other brands or types already running in the fleet? Does the casing allow use of the same design and width of retread to maintain simplicity of tire matching when replacing dual-tire assemblies? Do the casings require any special inspection procedures or processing techniques that might add complexity to normal retreading operations?
Casing warranty can also be a consideration. Key elements include the time limits of coverage, usually measured from the time of manufacture; any limit on the number of retreads covered; and a breakdown of what's covered by the casing manufacturer vs. the retread processor.
It's still a good idea to compare the values assigned to different casings - by their original manufacturer and local retreaders - in case your fleet generates excess casings or you need to buy casings to supplement new tire requirements.
Comparing tire casings is now easier than ever. A number of industry suppliers, including new-tire and retread manufacturers, as well as independent software providers, have PC-based recordkeeping programs available to replace hearsay with real data.
Since many casings in over-the-road applications today accumulate upward of a million miles and six or more years of service, you may have to rely on information from other fleet users.
Well-managed, cost-conscious fleets realize that it makes economic sense to put casing parameters - including durability, repairability, fuel efficiency, and post-original tread warranty - into the total tire-cost equation when they're selecting new equipment.
Spec'ing new tires without taking into account casing performance during the retread cycle isn't much different from evaluating our lives based only on accomplishments attained before the age of 30.