A treasure of a very special kind is stored in a vaulted cellar in Freising: discarded bicycle tires.

A huge amount of it.

For 20 years, a bicycle dealer in the city north of Munich has been collecting used tires in the hope that there will one day be a sensible way to recycle them.

At least in the case of this heap, which has been growing over time, this has prevented the tires from escaping the usual route of incineration or disposal in what may be dubious ways.

Walter Will

“Technology and Engine” editorial team

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Now the solution for the rubber mountain has apparently come.

As the first bicycle tire manufacturer in the world, the Schwalbe company has succeeded in developing an "innovative and holistic tire recycling process".

Used tires are turned into raw materials, allegedly without waste.

In addition, according to the information, recycling avoids 80 percent of CO2 emissions compared to tire incineration.

"After decades of research", the "big breakthrough" was achieved in close cooperation with researchers from the Technical University of Cologne and the company Pyrum from Saarland.

Schwalbe wants to have used tires of all makes collected and is providing bicycle dealers in Germany – around 500 are involved right from the start – with special boxes, each with space for 200 tires, which will be picked up by the logistics company Emons and transported to Dillingen.

There they get into the hands of Pyrum and are fed into a patented pyrolysis process.

In 2015 the recycling of hoses was started

The mechanical crushing takes place in four stages;

It is said to be more difficult than in the case of car or truck tires because of the finely divided components of bicycle tires.

Magnets fish out steel particles, suction cups separate textile fabrics from the rest. According to Pyrum, one ton of used tires results in 100 kilograms of textile fibers, 150 kilograms of steel and 750 kilograms of rubber granules.

The latter is treated by pyrolysis in Pyrum's 25 meter high reactor at around 700 degrees in the absence of oxygen, resulting in three pyrolysis products, the company explains.

These three products are gas, which is used to power the plant, oil that is purchased by the BASF group and used, for example, in the production of textile fibers, and pyrolysis coke.

This coke is further processed into recovered carbon black (rCB), which can be used as an alternative to carbon black from fossil fuels (vCB) in the manufacture of new tires.

Schwalbe announced the rCB would be delivered to manufacturing partner Hung-A's tire plant in Indonesia.

Pyrum calculates that from the 750 kilograms of rubber granules mentioned, 190 kilograms of gas, 250 kilograms of oil and 310 kilograms of coke would be extracted.

In 1993, Schwalbe took the first step towards not burning old tires but recycling them by downcycling them into rubber mats.

"Technically, it was no longer possible back then." The recycling of hoses began in 2015 - according to the information, seven million pieces to date.

Now follows a much more difficult task, the transfer of tires consisting of numerous ingredients into a material cycle.

"I'm really proud that we made it," says Schwalbe Managing Director Frank Bohle.

The first Schwalbe product that does not contain vCB, but only rCB from recycled tires, is to be presented at Eurobike 2023.

They also want to have the historic pile of tires picked up from Freising.

Although it might even have made a nice tourist attraction.