Products for Commercial Specialty Vehicles

ContiEarth™ iTires

The Korbach nailbiter

Continental makes commercial specialty tires in Korbach, Germany – the only ones that still come from a western industrialized country. This was made possible by a machine that resourceful employees developed themselves.


Driving along the twisting roads in northern Sauerland, you pass pretty reservoirs, hilltop forests, and idyllic villages of half-timbered houses with geranium and begonia flowers spilling over their wooden balconies. Not exactly the breeding ground you would imagine for a high-tech facility. And yet it is here, in the small district town of Korbach, that high-tech solid rubber tires for forklift trucks, low-loaders, and tractors are manufactured using cutting edge automated production techniques – the only facility of its kind in the world.
For decades, various manufacturers tried in vain to simplify the complex base manufacturing process for special tires. Nearly all of them gave up, but employees at the Continental plant in Korbach had faith and fought for their idea: a new type of base winding unit that would "marry" the rubber with the wire rings inside the tire in one go. There would no longer be the need for a dozen people to feed the wire in manually, bit by bit.

"Two long-serving colleagues in the team were familiar with earlier attempts and decided to develop them further," remembers Stephan Disselhoff, then head of Industrial Tire Production at Korbach. They temporarily converted an existing system and equipped it with a reel of wire. "I knew we could do what we wanted with the existing technology," explains Hartwig Poqué, one of those who helped develop the machine. His boss traveled to Hanover, presented the idea, and wrote applications for funding. But there was still a long way to go before the first automatically produced base rubber rolled off the production line. "On Sunday mornings, when there were no shifts on duty and the machines were free, we would stand here and wind wires," says process engineer Siegbert Steuber with a grin. "Then on Monday mornings, we would cut up the tire and look inside. Still no good! Every time, we were biting our nails, excited about the outcome."

Flexible miracle machine

The base is the most important section of a solid tire for commercial vehicles. For a tire carrying capacity of up to 11,000 kg, the base rubber must be absolutely reliable. What is more, the new machine had to be able to produce various tire sizes – also in small batches. "Until that point, it had only been worth producing large amounts," explains Ralf Jacob, an electrical engineer who looked after the control technology at that time. The new machine had to be much more flexible.

The Korbach employees traveled back and forth to the Black Forest to visit the supplier tasked to build the miracle machine. They watched over the shoulders of the designers as they drew and tested the software that was to control the machine. The first dry run failed. Head of Production Stephan Disselhoff was having trouble sleeping.
But the time finally came at the end of 2008. Within three weeks, the inventors were setting up their new base winding machine (known as WBA) in Korbach, over the Christmas period to take advantage of the plant shutdown. A lovely Christmas present that the Conti employees were able to give themselves.

Still going strong

The real work now began in earnest. The system was recalibrated several times, tinkered with, and optimized. Helmut Oberlies, responsible for maintenance, got hold of hundreds of spare parts. The first seven hundred tires went into field testing with selected customers. Every detail of the performance was recorded, the data analyzed. Only once the department for research and development gave the green light could the new made-in-Korbach tires go on sale.

"Our small, effective team proved that, with good ideas and strength of purpose, it is possible to move mountains," says Stephan Disselhoff, still obviously thrilled. The team were granted a patent for their invention. Siegbert Steuber, Hartwig Poqué, Ralf Jacob, and their colleagues have long since moved on to new projects.