Protecting that casing is key since it's the foundation for any tire, retread or not. "If you don't have a solid casing to begin with, it doesn't matter how good the retread process is," says Tolman. "If that casing fails, the tire fails."
Maintaining proper inflation pressure also helps a tire retain its proper shape. "It's important for the tire to operate at its right shape," says Dutcher. "The tire has to control and stop/start the vehicle, as well as give a good ride. It can't do that if the tire doesn't have the right shape."
When injury occurs to a tire, make sure you manage it properly. "If you get a cut in the tire and leave it alone, it will get worse," says Dutcher. "Manage those injuries by having a concise and thorough inspection program. Operators should look at tires multiple times a day. If they see an injury, report it to determine if it needs immediate attention."
Depending on the severity, a tire can still be retread even if damaged. "You can retread a tire that has been punctured," says Chris Hoffman, product manager, global tire products, Bandag. "There are procedures we follow and rules about what punctures can and can't be retread."
Bandag puts all casings through a 14-point visual inspection, as well as an electronic inspection that includes high voltage and shearography, where the casing is put under a vacuum and inspected to measure surface anomalies and expanding pockets of air that may make it a poor candidate for retreading. "We're able to look at the casing from bead to bead and see what may have been missed visually," says Hoffman. "That allows us to make sure that casing will last for [life of] the retread."
A tire should be inspected several times to ensure it is capable of being retread. Many tire manufacturers have field representatives who work with local tire dealers to provide an initial on-site evaluation to determine the retreadability of a tire used in a particular application.
Application is a primary consideration, since tires used in off-road situations can go through a wide variety of operating conditions, even on the same machine. "You have to look at each tire individually," says Tolman. "Consider where the tire has been used and under what conditions it has been operated. Consider if it is operated in extreme cold or heat, which may have caused more stress to the casing. Also consider if it has had more exposure to hitting and maneuvering around objects that may have caused internal damage that isn't easily visible from the outside."
Once application has been considered, and the tire has been through an initial inspection by the manufacturer/dealer, it goes through a second inspection at the retreading facility. In recent years, there have been many enhancements in technology to improve the retreading process. One of the main ones is nondestructive testing to ensure a casing is up to the challenge.
"About 10 to 12 years ago, the best testing procedures retreaders had was an inspector," says Brodsky. "He wore magnifying glasses and had good light, but he couldn't look through the tire and see if there was any damage that wasn't visible to the eye. Now, we have shearography machines, laser devices and x-rays that are being used and are becoming commonplace. We are able to give a worn tire the equivalent of a CAT-scan or MRI. We can look through to see if there are any steel cords that are damaged that would prevent the tire from enjoying the next life trouble-free.
"Because of that," he adds, "we are able to say that retreads have an adjustment rate (tire loss due to manufacturer defects) that is lower than new tires."
Manage the environment
Since application plays a vital role in casing health, it's also important to manage site conditions.
"We find a lot of damage can be done to a tire that renders the original tire out of service, as well as the casing and the ability to retread it," says Tolman. "Keep service roads and working areas clean. If you have areas where you're running over a lot of debris, you can cause unnecessary damage to the tire, the tread and the casing."