Retread on Me

New tires or retreads for school bus fleets?

By Denny Coughlin, Contributor

Are retreads safe and do they actually save money? Most fleet managers have a definite opinion on this question. If the answer is clear, why doesn’t everyone agree? Let’s examine the pros and cons.

First, let’s review the rules for those who everyday are not in the bus garage trenches. Front tires must be new; retreads (also referred to as recaps) at this position are not allowed under any circumstances.

New tires are the more expensive option when you replace the rear tires. If that is the case, why would anyone do this in a budget-squeezed industry? There are actually a number of good reasons depending on a number of variables. For fleets running in areas where standard highway treads can be used at all positions, they can rotate the tires from the front axle to the rear and vice versa. If you experience an alignment problem and the front tires develop a wear pattern, they could be swapped with the rear tires and run out the life of the tread on the rear with no adverse affects. The legal limit on front tires is 4/32 of an inch of tread depth, and for the rear it is 2/32 of an inch. Tires nearing the limit on the front can be rotated to the rear for a few more thousand miles. While the cost of new tires may run around $265 each, there is a casing value. Depending on the size of the tire and the demand for good casings in your area, you may be able to sell your casing for $35 to $75 each. This casing value can help offset the increased cost of the new tire.

Some fleet managers hold the belief: “For the precious cargo we are transporting, I don’t want to risk a tire failure with retreads. This is not the place to try to save money.” As a fleet manager, I can respect that opinion, but with a few precautions I consider recaps safe. While a recap separation is not impossible, let’s consider our application. Most of those treads that come loose are from over-the-road trucks, and even those that do are often from new tires. Trucks are usually loaded heavy, run long distances and have weight and heat working against them. A tire low on air pressure can be a death wish for any tire, new or recap. School buses, on the other hand, typically are not loaded to capacity. They run at lower speeds for shorter periods of time and are checked regularly for pressure. Our operational characteristics alone greatly lower the probabilities of retread failures.

Many parts of the country require rear-traction tires for mud and snow conditions. This eliminates the option to rotate from the rear axle to the front. Grip-type tire treads are very economical to purchase in retreads, typically costing from $100 to $125 providing we furnish the casings. The reliability of the retreads today is also very different than it was 30 years ago. Those in the retread industry may point out the casings are already proven reliable. The tire casings are ground down to a specific shape removing all the original tread. This shape or curvature is required to assure 100 percent contact when the recap is attached. The casing is examined with high-tech electronic equipment that can detect breaks in the steel cords, holes in the rubber and sidewall damage. Industry standards dictate what are allowable defects, the repair process and criteria that disqualify a casing from being recapped. The vulcanizing process bonds the tread cap to the casing to make it one unit. This process includes baking the finished product in a chamber for a couple hours at about 250 to 300 degrees, often in a vacuum-induced envelope to force the cap onto the casing during this process. The reliability of the retread tire today is extremely good.

One key to reliability is the casing used. I insist that all retreads be done on our fleet casings. I know our tires have not been overheated or overloaded and do not run low on air. If we have a tire that was run low, possibly damaging the side wall, we mark the tire as scrap. Since we must purchase new tires for the front axles, we have a constant supply of good casings to retread. The sidewalls must be branded (with a universal code) each time the casing is recapped. Each casing will indicate the number of retreads and the dates of the retreads.

There are two grades of casings: “A” casings are those that have not been through a retread process, referred to as a virgin casing; and “B” casings are those that have been retread at least once. “A” casings usually have a higher sale value. Do I think retreads are reliable? Let the record speak for itself. In our inter-city fleet of 150 Type C buses, we have had one retread separate in 23 years. We had about four casings blow out within six months, initiating an investigation that revealed we were retreading our casings too many times. We learned from our mistakes, and our new policy is to recap only once if possible. And we sell the casing after we wear out the original tread and the first recap.

Each fleet manager has two good options, new or retreads for the rear axle. We all need to periodically evaluate how we do business. This may be a good time to take a fresh look at the market in your area to determine the price of new and retread tires, the casing values, the life you get from both and see how the numbers calculate. Then make a decision incorporating your policies and best judgment. The results will not be the same for everyone.

Coughlin is the fleet manager for Minneapolis Public Schools, which operates 215 school buses and 175 district support vehicles.