It’s amazing to see all of the different ideas and philosophies being used to run an intensive school bus tire program. Some folks tend to do only what’s necessary, while others aren’t sure what to do. Here at the School District of Palm Beach County (Fla.), we have some basic practices we follow that work for us and may work for you. I certainly don’t claim to have all the answers, but we have done a lot of research and testing to back up our theories. We have about 750 school buses in our fleet, with a mixture of makes and models. We also maintain a large fleet of support vehicles that includes 800 trucks, vans and cars. Here are some of the “best practices” that we’ve put together to maximize the safety and efficiency of our tires:
1. Never change only one steer-axle tire, except on an emergency road call basis. Even if the “good” steer tire is almost new, we replace them both. The good one can be used to match another tire that can be installed as a pair. This will maximize attainable mileage both on new and used tires.
2. Match tread on drive tires. This should be obvious, but some folks don’t take it seriously. We match the same tread pattern to within 2/32”. If both rear tires are a highway pattern, but not the same design, they can be used; however, you must measure the overall diameter, not tread depth, and match to within 1/4” for the best performance and longest life. Do not mix lug tread and highway tread tires. They wear at different rates, and one tire almost always ends up doing the work of two, and subsequently fails.
3. Remove the new tires from the rear of new buses and store them for future steer axle use. Install matching retreads on spare rims and mount them to the rear of the new buses. They last as long as original-tread tires at approximately one-fourth the cost! (We remove $840 worth of tires and install $220 worth. Now we can add four new steer tires to our inventory at no cost.)
4. We spec Michelin XZE radials on our new buses. This adds about $90 to $100 to the price of the bus (radials are standard on our bus bid) over the standard radials, but adds about 40 percent to the attainable mileage.
5. We “bit the bullet” a few years ago and specified steel disc wheels and tubeless tires. Ease of maintenance and additional miles on each tire have more than paid for this change. Also, we went to hub-piloted wheels this year in an effort to further reduce parts spending (fewer lug nuts required). Plus, these wheels are easier to install and the flanged lug nuts have better clamping power.
6. One last deal that’s going to save us money: We went to 11RX22.5 tires in lieu of the standard 10RX22.5. The reason for this is that nobody wanted the 10R casings after we were through with them, and we were forced to pay to have them hauled off. The 11RX22.5 size is used by many trucking and bus companies that will gladly pay us for good, usable casings. After our third recap wears out, we scrap the casing to ensure quality casings in our fleet. We can get $40 to $75 each for them as opposed to paying $3 to $8 to have them hauled off! Some people have looked twice at our 47-passenger conventional bus with 11RX22.5 tires on it. When I explain the program, however, most folks end up with a positive opinion of this procedure. (I haven’t mentioned air pressure as an obvious aid to increase attainable mileage because every article ever written about tire maintenance has discussed that issue at length.) Our program works for us, and we have a large, high-mileage fleet (17 million miles per year on routes alone) that demands the best. Hope these tips can help you too!
Joe Reed is assistant director of transportation/maintenance at the School District of Palm Beach County in West Palm Beach, Fla.