retread

Retread is the process of restoring a worn tire by applying new tread rubber to an existing tire casing. It is most commonly used for commercial tires, such as those on trucks and buses, though some passenger-car tires are retreaded in select markets. The goal is to extend the life of a tire by reusing the durable casing while replacing the worn tread.

The retread process typically begins with casing inspection to assess structural integrity, including checks for ply separation, cracks, bead damage, and other defects. If the casing passes, the worn tread is removed or ground away to a uniform base. Any repairs needed to the casing are made, and a bonding layer is applied to promote adhesion. Tread options then enter one of two main paths: precured (precured tread) segments are bonded onto the cleaned casing, or a full-depth tread is built up and cured in a mold (full retread). In the latter case, the completed tire is cured under heat and pressure to fuse the new tread to the casing. After curing, the retread is trimmed and subjected to final inspection and testing.

Standards and safety considerations vary by region but generally require rigorous inspection and certification to ensure performance and reliability. Retreading can reduce material use and waste and often lowers cost per mile compared with new tires, though performance characteristics depend on casing condition, tread type, and operating environment.

In everyday language, retread can also mean to retrace or revisit a path, topic, or idea.