Tire retreading: How Retread Tires Are Made
Retreading tires is a common practice for heavy machinery that helps to prolong the tire’s service life while saving costs and the environment. In fact, in Scandinavia, almost all truck and bus tires are retreaded after they have been worn in use. Therefore, tire retreading is an integral part of the whole tire management process and a smart way to give a new tread life to worn tires.
With carefully developed and optimized tire retreading processes and materials, you can give your heavy tires a second or even a third round. Tire retreading is also a safe alternative for buying new tires, as the whole process is strictly controlled by legislation and authorities. Therefore, a retreaded tire is comparable to a brand-new one.
Retreading gives old tires a new life
Tire retreading, also known as recapping or remolding, involves removing the old tire tread and applying a new tread, guaranteeing the tires’ safety in use for another service life.
The structural framework or body of the tire provides the tire with its shape, strength, and flexibility. This part is also known as a tire casing or tire carcass. Even if the old tire’s tread rubber has worn out in use, the tire casings can still be reused by retreading.
Choosing high-quality tires is an essential for retreading them after the original tire tread has worn off. With quality tire casings, it is possible to retread the tire several times, as premium tires are designed to be retreaded. With multiple retreadings, a single tire casing can be driven for up to a million kilometers.
An environmentally-friendly retread tire
With retread tires, you can save in tire costs up to 50 % by retreading the same old tire casing twice. In addition to saving on costs, you also save valuable materials used in the tire manufacturing process, thus decreasing the tire’s environmental effect and the need to produce raw materials for new tires. For example, by using retreaded tires instead of buying new ones, you can save about 70 liters of oil and reduce the carbon footprint of the tire by up to 75 %.
Waste from discarded tires is another concern that retreaded tires solve. Tire manufacturing is an energy-intensive process, and less energy is needed to produce a retreaded tire once the tire carcass has already been produced.
The Nokian Tyres E-tread product line helps to save raw materials and energy even further by using a recycled surface rubber compound from the Nokian Tyres production line.
The process of retreading tires
Manufacturing all tires requires various valuable materials and parts that do not need to be wasted after the tire has gone through one service cycle. Reusing as much of the tire is all the more important with large machinery, such as trucks and buses, that require heavier tires than lighter passenger vehicles.
The tire casings of heavier car tires is beneficial thanks to the retreading process. Here’s how the tire retreading process works:
- Inspection. The tire retreading process begins with examining the worn tire. There are several machines to help in inspecting, but the most important thing is an experienced operator. Only quality tires should be retreaded, which is why opting for cheaper alternatives is not cost-effective if you want to maximize the service life of your tires. Our Nokian Tyres Noktop tire retreading uses only quality tire carcasses, which are retreaded with a new rubber compound.
- Buffing. Once inspected and approved, the tire’s worn tread pattern is removed by buffing it away. This makes room for a new tread pattern. The tire is inspected again once the old tread is removed to identify any damage that was not previously visible.
- Skiving. All the punctures and penetrations are opened and filled again. If there are any deeper punctures, a batch is applied.
- Cementing. A specialized adhesive for Noktop tire retreading is sprayed on the tire casing. The adhesive prevents the oxidation of the buffed surface and also improves the raw adhesion of the tread.
- Cutting the tread. The new tire tread is prepared for installation on the reused tire casing. The tread is cut to a specific length just right for the measured tire size.
- Building. Now that the casing is prepared, the new tread is assembled on it. The cushion gum, which bonds the casing and tread together, is first applied either to casing or to the new tread. Then the previously prepared tread is attached on the casing. After the tread has been precisely attached to the casing, it is stitched to ensure there is no air between the casing ant the tread.
- Curing. After the building phase, it is placed in a curing bag called envelope and vacuumized. Now, the tire is ready to go into a curing chamber to be cured under a high temperature and pressure. The conditions need to be just right and carefully controlled.
- Final inspection and finishing. After a final inspection and a paint finish, the retread tire with a brand-new tire tread is ready for the road. With a high-quality tire casing, the same tire can go through this tire retreading process two or even three times, thus extending its service life, reducing costs and minimizing the environmental impact of tires.