Retreading Process

Retreading Process.Click below for more information about the retreading process Why retreading "Hot" retreading

"Cold" retreading

Why retreading:
Retreading is a safe, efficient and environmentally friendly way to breathe new life into worn tyres: The "worn-out" tread of the tyre is replaced with a brand-new one and this means that the tyre can be used again!
Unfortunately, however, not every tyre can be retreaded. The requirements are:

	The tyre was used correctly in its "first life", driven with the right air pressure and treated with care.
	The tyre's frame, the carcass, is not seriously damaged.

In addition, whether a retreadable carcass can be reused depends on the type of tyre. The following retreading limits apply:

	Car tyres: 1 time
	Light truck tyres: Generally 1 time

Truck tyres: 1 to 3 times

Aircraft tyres: Up to 12 times

There are two techniques for retreading:


Hot retreading or Precure "cold" retreading.

The benefits of retreading are that it is both environmentally friendly and cost-efficient!

When the tread has worn off, only about 20% of the tyre is used up. The carcass, which represents about 80% of the tyre's value, can be re-rubberised for a "new tyre life".

To produce a truck or bus tyre requires about 60-80 kg of rubber mixture. Retreading the tyre takes only about 15 kg of rubber. A considerable amount of raw materials can therefore be saved. In the EU, this equates to more than 300,000 tonnes per year!

To produce a car tyre requires about 28 litres of crude oil. To retread a car tyre, on the other hand, only 5.5 litres of oil are needed.

Retreading saves over 500,000 tonnes of crude oil in the EU every year.

Retreads save the user a great deal of money, since they will do about the same mileage as new tyres, but cost only 45-60% of the price of a comparable new tyre.

While retreading does not eliminate the need to dispose of old tyres, it does delay it considerably. This helps keep down the fast-growing cost of disposal and takes the pressure off landfills.

Retreads and their place on the market


The proportion of retreads on the replacement car and truck tyre market in Europe still varies widely.

For car tyres, retreads make up only 1-2% of the market in Switzerland and the Netherlands, but this figure rises to over 20% in Scandinavia. In Germany, retreads account for around 10% of car tyres, a proportion which rises to 20% for winter tyres.

For truck tyres, the proportion of retreads is much higher, ranging from around 40% in Spain to over 70% in Finland. In Germany and France, retreads make up around half of the replacement tyre market for trucks. Over 15 million truck and bus tyres are used every year across the EU. Of these, around 8 million are new tyres, and over 6 million are retreads.

Retreading plays a particularly important role in aircraft tyres, which are subjected to extreme stresses. Aircraft tyres have to withstand huge strain at speeds of over 250 km/h, and undergo retreading after around 150 take-off and landing manoeuvres. Retreading can take place up to twelve times. The testing procedures are naturally very stringent here, and safety takes top priority.





High-quality retreading is the alternative to new tyres for commercial vehicles, since it offers safety, top running performance and an excellent cost-benefit ratio. More and more consumers are recognising and coming to appreciate the positive image of high-quality retreads.

"HOT" retreading:


Hot retreading involves the vulcanisation of a tyre in a mould at a temperature of around 150 °C. The tread and the sidewall veneer of the tyre are made up of non-vulcanised rubber compounds. The shape and tread of the tyre are created in the heating press.

Arguments in favour of hot retreading:

	Suitable for all tyre applications, including car and aircraft tyres.
	Material costs are lower than the more complex products required for precure retreading.
	Hot retreading also allows extensive repairs to be carried out on the tyre carcass (e.g. belt replacement).
	Even bias-ply carcasses can undergo hot retreading without any problems.

Points to note:

	A separate mould is required for each tread and size. This requires a high level of investment in a range of moulds, which will be need to be regularly updated.
	The production process needs to be designed for large numbers of tyres. This calls for a central production workshop, an extended customer area and therefore brings with it relatively high logistics costs.

"Cold"  retreading:

 

Precure or "cold" retreading involves vulcanisation without a mould at a temperature of between 95 °C and 110 °C. The tyre is put together using a pre-vulcanised tread liner (= new tread) and a non-vulcanised bonding gum layer. The bond between the carcass, the bondung gum and the precured tread is created in an autoclave. Precure retreading has become fully established in the truck tyres sector since the introduction of radial tyres in the mid-1960s.

Arguments in favour of precure 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 tyre application.
	The comparatively low investment costs involved mean that decentralised, smaller production units can be operated. This means lower logistics costs and makes the operator more flexible and closer to his customers.
	The precure retreading process is kind to the carcass, since vulcanisation temperatures are lower and put less strain on the rubber-metal bonds in the carcass. Heat build-up in the tyre, rolling resistance and other tyre properties are often easier to assess than with hot retreading.
	With comparable tread geometries, the running performance of a precured retread is often better than a hot retread and the same as an equivalent new tyre.

Points to note:

	Precure retreading requires high-quality carcasses.
	Material costs are higher than hot retreading material, since the precured tread is already vulcanised and is therefore a more heavily-processed product.
	Labour costs per retread are higher than for hot-retread truck and bus tyres.