The process of renewing a used tire consists in replacing the rubber and rebuilding its original structure. It is a very complex process from a technical point of view, but with a perfect knowledge of the product, and demanding means of production and quality control, a new tire with the exact same characteristics as the original is achieved. All this thorough technological process together with a perfectly well trained team allows INSA TURBO to guarantee the final product’s quality.

  1. The rubber used in elaborating the pattern has a special formula of ingredients designed for each type of tire, providing it with performance, handling and grip.

2. The final pattern of the INSA TURBO tire is obtained after the molds apply high temperature and pressure on the rubber.

3. The casing is buffed and treated with special adhesives for a perfect bond between carcass and tread.

4. The casing keeps its original structure to keep its characteristics.

Renewing a tire takes all these stages:


The initial inspection that used tires must undergo is possibly the most important step of the whole process.  This stage determines whether the tire is suitable for retreading or if it presents irreparable damage, manufacture imperfections or if it is too old.

1. 1. Visual inspection.

External: The tire is checked for visible belt separation, oxidation, deep or wide cuts, twisted or broken beads, excessive cracking, age, etc.

Internal: The inner side is examined for soft or porous wall, holes, punctures, etc. All the data is written to keep a record.

1. 2. Pressure inspection.

The tire is inflated to 2 BAR and if no problems are detected, pressure is raised to 8 BAR to detect cables separation or hernia. If the tire does not comply with the safety requirements, it is rejected.


The shearographer measures changes in the structure of the tire under stress. The casing undergoes strong inflation and deflation processes while a laser scans the inside of the tire. Any asymmetry in the structure is detected by comparing both situations. Then the degree at which anomalies will be formed when the tire is inflated at running pressure.

Only the best tires pass this inspection and are not rejected and taken into a different recycling process.


Once the tire has passed the inspection and is suitable for renewal, is taken into buffing. In this stage the old rubber is eliminated mechanically and a rough surface is left ready to apply the new tread. In INSA TURBO this process is controlled by a computer. We use high technology machines with buffing blades that leave a perfectly adherent surface in the top of the tire and a perfect balance. Very often a buffed casing is left rounder and balanced than it was originally.


In this phase of the retreading process the tire is inspected again. Without the tread some minor imperfections or damage may become visible, like belt separation, oxidation, holes, etc.

1st Step

After the casing has been buffed, the cavities are repaired, leaving the casing ready for the following step.

2nd Step
The cavities that have previously been buffed and repaired are refilled with new rubber.

3rd Step
With an AZ-Extruder a 1mm layer of bonding rubber is applied to the crown.