“Cold” retreading:
Pre-cure or “Cold” retreading involves vulcanization without a mould at a temperature of between 95 °C and 115 °C. The tire is put together using a pre-vulcanized tread liner (= new tread) and a non-vulcanized cushion gum layer. The bond between the carcass, the cushion gum and the precured tread is created in an autoclave. Pre-cure retreading has become fully established in the truck tires sector since the introduction of radial tires in the mid-1960s.
Arguments in favor of pre-cure retreading:
- Less investment is required on the part of the retreading plant (no expensive moulds) and lower follow-up costs, since it is the material supplier who updates the range of moulds.
- A wide range of tread types are available, allowing the optimum tread to be selected for the tire application.
- The comparatively low investment costs involved mean that decentralized, smaller production units can be operated. This means lower logistics costs and makes the operator more flexible and closer to his customers.
- The pre-cure retreading process is kind to the carcass, since vulcanization temperatures are lower and put less strain on the rubber-metal bonds in the carcass. Heat build-up in the tire, rolling resistance and other tire properties are often easier to assess than with hot retreading.
- With comparable tread geometries, the running performance of a pre-cured retread is often better than a hot retread and the same as an equivalent new tire.
Points to note:
- Pre-cure retreading requires high-quality carcasses.
- Material costs are higher than hot retreading material, since the pre-cured tread is already vulcanized and is therefore a more heavily-processed product.
- Labor costs per retread are higher than for hot-retread truck and bus tires.