Retreading is the generic term for tyre reconditioning which extends the useful life of a worn tyre for its original purpose by the addition of new material.
In the majority of cases the tread rubber is the only part of a tyre to wear away. The structure of the tyre remains intact. As the tyre construction has been produced to be capable of more than one life, to use this potential by replacing the worn tread makes sound environmental and economic sense. Whilst a car tyre is retreaded only once, commercial vehicle tyres are often retreaded two or three times and aircraft tyres many times.
After Initial Inspection of the worn casing to judge its acceptability for processing, the remaining unwanted old tread is removed. This process is called BUFFING and it provides a profile and surface texture in preparation for the application of a new tread.
The application of a new tread and sometimes sidewall veneer is the next stage. This is called the building process. There are two main ways of building a retreaded tyre. With the hot cure or mould cure process, uncured tread rubber is applied to the casing, usually using a strip-winding machine. In the cold cure or pre-cure method a pre-cured tread strip is applied to the casing. When the operator is satisfied that all criteria have been met the built tyre then moves on to the curing operation.
After curing, a FINAL INSPECTION is made to rule out any defect which would impair serviceability or the safety of the user. Unacceptable tyres are rejected and scrapped.