Basically, there are
two systems used to retread a tire, Mold Cure and Pre Cure.
The reason both systems exist is because of the economics of operating a
retread plant and have nothing to do with the quality of the finished product.
Each system has unique advantages but both systems produce equally good
The initial steps in retreading a tire are the same regardless of
which retreading system is used. These steps are:
1. Primary Inspection. Each tire received in a retread plant is subjected
to a very rigorous visual inspection. Inspectors may be assisted by the use of
various non-destructive sophisticated inspection equipment available in the
retread industry. As many as 85% of passenger tires are rejected. The
acceptance rate for truck tires is higher due to the better care taken for and
the stronger construction of a truck when compared to a passenger tire. Only
the very best proven worn passenger and truck tires get past this inspection.
2. Buffing. After inspection, tires have the old tread mechanically
removed on high speed buffers. Today's buffers are extremely accurate and will
remove the proper amount of old rubber while truing the tire to an exact
specified diameter and radius.
3. Application of new rubber in the tread area. Here is where the systems
a. In the pre cure system, the tread
rubber has already been vulcanized with the new tread design. The buffed tire
has a thin layer of cushion gum wrapped around the tread area and the pre cured
tread is then applied. The cushion gum serves to bond the pre cured tread to
the tire. The tire is then placed in a curing chamber and the pre cured tread
becomes adhered to the tire through a vulcanizing process very similar to that
used in new tire construction.
b. In the mold cure system,
unvulcanized tread rubber is applied to the buffed tire. The tire is then
placed into a rigid mold which contains the tread design in the tread area. The
mold is heated and the rubber in the tread area vulcanizes and adheres to the
tire with the new tread design molded in. Again, this vulcanization process is
very similar to that used in new tire construction.
Note: Both systems require a combination of time, heat and pressure to
create the vulcanization of the new rubber to the tread area of the tire.
4. Final inspection..
The retreaded tire is subjected to a final inspection. This inspection insures
that only tires that meet industry quality standards are allowed to leave the
5. Trimming and
painting. The retreaded tire that successfully has passed the final inspection,
is trimmed to remove any excess rubber and painted. It is then ready to return
to full service and a second (or third) life as a safe and economical
alternative to high priced new tires.
6. Nail hole and
section repairs: When required, nail hole and section repairs are
performed within the retread industry repair guidelines. These repairs are made using the latest technology and proven
repair materials. A properly repaired tire can be put back in full service.