A Century Of Retreading

According to Kraiburg Austria, 2006 marks the centenary of retreading and, the company argues, giving new life to worn tyres is as important today as ever it was. The experts are not in total agreement, but many are of the opinion that the retreading of tyres started in 1906 in Germany, while 1908 is the year cited for England and China, and 1917 for the USA.

Thus, retreading is looking back on 100 years of history. During these years processes, technologies and safety regulations have undergone some revolutionary developments. The latest change is the most recent adaptation to meet UNECE regulations R108 and R 109 as of September 2006. These provisions detail safety and quality control standards for retreads, similar to those that apply to new tyres.

While over 50 per cent of the trucks, buses and trailers on the roads of the EU today are already running on retreads, experts expect this number to rise even further as a result of the new safety requirements. That will of course be beneficial to suppliers and processors in the retreading business, but the environment will gain too, as less energy is needed for the manufacturing process and fewer tyres will be wasted.

Today it is becoming increasingly important to handle tyres with care. Apart from the fact that it makes economic sense to ensure tyres run for as long as possible, there are ecological aspects, primarily to do with the shortage of the raw materials rubber and oil, along with rising prices. This phenomenon has a long history, too. After vulcanisation was invented in 1840, the consumption of natural rubber rose so drastically that in 1882 the cultivation of plantations was started. The largest plantations are in Thailand, Indonesia and Malaysia. Despite that, the demand remained higher than supply. Chemists worked for years on ways to manufacture synthetic rubber. Researchers conducted the first experiments at the end of the 18th century, but it was not until 1926 that Professor Fritz Hoffmann from Germany was successful. Artificial rubber was introduced to tyre production two years later.

Around the time of the Second World War, tyre retreading experienced a tremendous boom. Of course repairs had already been in great demand throughout the three preceding decades, not least because of the fact that new tyres were very expensive and only lasted between five and eight thousand kilometres. But in the forties vulcanisation shops shot up everywhere (with the tyre specialists predominantly doing the retreading in their basements). They processed everything that had anything to do with rubber, starting with boots through to bicycle, motorcycle and car inner tubes, plus tyres of all types. The process was far more complex compared with today’s standards. The area to be repaired was opened up, sometimes in combination with a sleeve individually suited to the tyre. An uncured, cross-shaped patch was then applied to the spot that had been opened up.

Before the introduction of a buffing machine in 1937, the buffing up process was the biggest technical difficulty for tyre retread specialists. Working purely by hand, they first buffed the spots to be repaired with a file, and then the running surface was treated three times by hand with a solution. When this was dry, a strip of rubber was laid on top, followed by a second, narrower strip. The craftsmen then painted this assembly with benzene for improved adhesion. A supporting circular spring was placed inside the tyre. Wrapped up in a wet tyre band, it then went into the heat chamber.

Bertram Emanuel went down in history as the pioneer of mould-cure retreading. In 1914 he was the first to establish a hot-cure retreading plant: the Homerton Rubber Works in East London. And by far the largest independent tyre retreading companies in Europe are still located in England to this day. The first plants in France and Finland started up in 1916, followed by Germany in 1921 and Italy in 1924.

The second common process in tyre retreading – cold-cure retreading – is based on a German invention. Bernhard Anton Nowak made some crucial innovations after the Second World War. He had the idea of laying preheated strips of tread with bonding rubber onto prepared casings, heating them up in the autoclave and vulcanising them in place. He set up his company near to Darmstadt, under the now globally familiar name of Bandag – Bernhard Anton Nowak Darmstadt Aktien Gesellschaft. A further chance occurrence took this technology from Hesse around the globe: An American happened to be passing through Darmstadt in 1957. While he was travelling in a taxi, Roy J. Carver’s attention was drawn to the tyres, which looked so different. The driver explained to him what it was all about. As a result the entrepreneur Carver met up with the visionary Nowak, and when he went back home he had the rights to the precure process in his pocket. From there it started on its march around the globe. The company is still number one today in the precure market, followed by Kraiburg and Marangoni.

Kraiburg Austria claims to be the leader in Europe. The company has been producing high-quality materials for tyre retreading for almost 60 years, and has been based in the Upper Austrian municipality of Geretsberg since 1965. The historic roots go back to the year when the company was founded, because back in 1947, Kraiburg was established in the German town of Waldkraiburg. Today the Kraiburg has 12 production plants in eight countries, producing a comprehensive range of products, providing the right tread design and the optimised compound portfolio for any and every application.