Scrap tire analysis helps fleet managers glean valuable information from casings.
To optimize casing analysis, make certain that ALL of the casings are included in the analysis, especially the return-as-received (RARs) as classified by the retreader, and at least a fair sampling of tires replaced over the road.
Every scrap tire can be placed in one of three categories. First, maintenance deficiencies, primarily underinflation, including detection of slow leaking punctures and equipment damage. These issues must be addressed by review and/or revision of maintenance procedures, both in-house and over-the-road. Be sure to include third-party inspection/maintenance providers when applicable. Another caution is to recognize that, while automatic inflation systems can maintain proper tire pressures, slow leaks, such as nail hole punctures can remain undetected without visual tire inspections, leading to eventual tire failure as high pressure air bleeds through the tire casing over time.
The second category includes road hazard cuts, accident or equipment damage, and driver abuse. Some of these instances can be avoided with special driver training and selecting the optimum tire type for your service conditions. Surprisingly, some fleets with urban delivery conditions and/or specialized equipment report that 5 to 15 percent of their new tires are damaged beyond repair while still running on their original treads. Linehaul fleets should have lower damage rates, but periodic monitoring, with solution oriented training, may lower replacement frequency and costs.
A third category is performance deficiencies from shortfalls versus written, implied, or negotiated warranties. The most obvious of these would be product workmanship or materials defects. However, these may extend to mileage shortfalls, extra service and/or maintenance requirements or casing related RARs upon incoming inspection at a qualified retreader. Remember that you will likely need hard data comparisons versus competitive tires, preferably on comparable equipment, to present a credible claim.
Many caveats apply to the above classifications. Soliciting the advice of qualified tire manufacturer engineers and talking with seasoned maintenance peers can help with data sorting. For example, what might appear at first as a defective new or retread tire may simply be the result of misapplication or possibly be caused by a lack of detailed fleet involvement in the spec’ing process or an ill-fated match of tire and vehicle for the expected service conditions or vehicle configuration. When specifying tires, fleets need to take into consideration the types of road surfaces to be traveled and the possibility of frequent and severe wheel cuts. Highly maneuverable, 55º wheel cut trucks do actually wear both steer and rear tandem tires faster than their 45º limited counterparts. High scrub resistant tires, which tend to be less fuel efficient than shallower tread linehaul tires, may be the most cost effective choice for urban delivery.
After establishing a scrap tire analysis program, there are still benefits to analyzing tire performance of competitive casings running in your fleet throughout their life cycle. Fuel efficiency is a good example. Many otherwise valid fuel economy comparisons have been jinxed by tire brand and/or tread type and stage of wear (tread depth) differences.
Significant portions of a modern radial tire’s rolling resistance come from the casing, while other portions come from the tread. Some casings will deliver improved fuel efficiency when compared to the same retreads on different brand/model casings.
Tracking the time that casings remain in your system is also informative, provided apple-to-apple comparisons can be made. Also, later life performance of retreaded casings can differ significantly by wheel position. High torque drive positions especially can be tolerated better by certain casing brands and/or models than others.