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Retreading
Retreading designates the technical process allowing the life
extension of a used tyre.
It basically consists in the replacement of the worn-out tread. The
retreaded tyre is brought back into the same service conditions
without sacrificing tyre road performances. This process may be
repeated as long as the casing integrity is guaranteed. The
production of retreaded tyres is mainly concentrated on truck,
passenger car, off the road and aircraft tyres.
To produce, retreaded tyres, two technologies are available:
- “Pre-moulded” or “cold cure” retreading
This process applies to truck and passenger car tyres. The new
tread that will be applied is prevulcanized to its final shape.
Casing and procured tread are crosslinked in an autoclave
through a special cushion compound. The advantage of this
process is its flexibility to produce small series of various
sizes and designs.
- “Mould-cure” or “hot cure” retreading
In this process, uncured tread cap compound is applied to the
buffed casing. The vulcanization takes place in a proper tyre
mould. This method applies to large volume production due to the
high investment and maintenance costs.
This retreading process involves six steps:
1) Initial inspection
2) Buffing
3) Tread preparation and building
4) Enveloping
5) Vulcanising
6) Final inspection
Details of retreading process
Key figures:
- Truck tyres are designed to be retreaded 3 to 5 times,
aircraft tyres up to 10 times;
- 41 % of truck tyres on the EU market are retreaded tyres,
i.e. more than 6.2 millions of tyres in EU15 in 2004;
Retreading positive impacts compared to the production of a
new tyre:
- Need of 5 times less energy and raw material;
- Reduction of the tyre cost per km for the end-user;
- Less tyre waste generated.
EU regulatory framework:
The Council Decision of 13 March 2006
lays down that from 13 September this year the provisions of UN/ECE
Regulations 108 and 109 shall apply as a compulsory condition
for the placing on the market of retreaded tyres on the EU Member
States market. This will ensure that retreaded tyres fulfill similar
safety and quality control requirements as new tyres.
This Decision that had been requested by the industry since late
90's, is welcome, as it will contribute to promote further the
retreading activity globally in enhancing the safe use of retreaded
tyres.
18 April 2006
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