Bicycle spokes made from high-tech fibres - Made in Chemnitz
Ingo Berbig & Dirk Fischer
Chemnitz can look back on a long and successful history in the textile industry. Its development into a textile centre began 660 years ago. Today, more than 200 companies and organisations are active in this industry in Chemnitz. But the work no longer has anything to do with textiles as it did over a hundred years ago. The proof is in the pudding: a working group at Chemnitz University of Technology has developed bicycle spokes made from high-tech fibres. And they want to use them to give everyone a run for their money. Two of them, Ingo Berbig and Dirk Fischer, answered our questions.
How did you come up with the idea of developing bicycle spokes made from high-tech fibres?
Ingo Berbig: It's actually quite simple: I've been cycling since 1994, including at the Chemnitz Cycling Club (RSV). I started studying mechanical engineering at Chemnitz University of Technology in 2000 and added textile mechanical engineering in 2003. I have been a member of staff at the Chair of Conveyor Technology since 2006. This resulted in a very interesting field of work: we researched high-performance textile fibre ropes. I have now been working in this field for almost eleven years.
Then I more or less combined my hobby with my job. I basically know about the nature of spokes in a wheel (editor's note: wheel refers to the entirety of a front or rear wheel on a bicycle).
I knew that the use of high-quality high-tech fibres was possible and then we tried it. As we now know, it works.
How long did it take to go from theory to the finished product as we see it now?
Ingo Berbig: About three years. We tried it out first. Then we went to companies with our idea and asked whether they were interested and would like to develop it together. Interest was rather low. This was perhaps also due to the fact that our concept was not so convincing for the others at the beginning. We, on the other hand, were completely convinced and ended up realising it ourselves.
Dirk Fischer: We dealt intensively with the topic in my master's thesis, which Ingo supervised. In my thesis, I realised a front wheel. That was our first real prototype. With this work, we were able to apply for a grant from the Federal Ministry for Economic Affairs and Energy (BMWI) and received financial support. This gave us more opportunities to realise the idea.
Normally, spokes are made from metal or, for ambitious cyclists and professionals, from carbon fibre. The use of high-tech fibres is new. "Our bicycle spokes are made of high-strength polyester, which are special fibres that we work with at the TU," explains Ingo Berbig. This not only saves weight, but also increases stability. In this day and age, when everything is supposed to be more sustainable, that's an almost unbeatable argument.
What are the advantages of your spokes over conventional ones?
Ingo Berbig: We intend to offer a system wheel (editor's note: with system wheels, individual manufacturers change parts and construction methods of wheels in order to ensure choice and interchangeability), where the customer has the opportunity to say what they actually want. It is more individual than the system wheels that can be ordered from the catalogue. With us, you can choose the components: A stiff or an elastic wheel to achieve more comfort, the number, arrangement and colour design of the spokes. The wheel is customised to the user's needs and preferences.
Our spokes are generally lighter than steel spokes. In our case, the more spokes there are in the wheel, the more weight we can save with our spokes. If you pay extreme attention to weight, we can reduce the front and rear wheel to a total weight of around one kilo. But as I said, that's not everything. We basically want to offer flexibility in use.
Our design is also safer: if you compare the longitudinal force that steel spokes can absorb with ours, the standard spokes can absorb around 2500 newtons before they break. Our construction can absorb approx. 4000 newtons.
Dirk Fischer: Our advantages over carbon, which is also very light, are that our spokes are generally less expensive and, as an elastic element, give way slightly in the event of a bump. This minimises the risk of damage. In addition, there is a protective sheath around the fibre that absorbs the shocks. The fibre and therefore the spoke are not damaged. It is safer and also more durable.
As a rider, do you notice a higher level of comfort?
Ingo Berbig: Certainly. On mountain bikes or city bikes, for example: Here, people want to ride comfortably on uneven surfaces. Impacts and bumps lead to rider fatigue in the long run. Our wheel offers the possibility of compensating for impacts that are transferred from the ground to the rider.
Not only bicycles, but also wheelchairs can benefit from your invention?
Ingo Berbig: That's right. Wheelchair users also use wheels with spokes. They are interested in less weight. With our wheel, less power is required for the drive. Furthermore, transporting wheelchairs with a lower weight is more comfortable.
If you think not only about the normal use of wheelchairs, but also about wheelchair sports, such as basketball or long-distance sports, then we have the option of producing a suitable wheel depending on the application, apart from the steel spoke. In basketball, athletes drive into each other's wheels and damage is caused to the metal spokes. There are real bends and thus a failure of the wheel. As already mentioned, our spokes do not absorb the forces, but give way and return to their original position after loading. An advantage in this sport.
You shouldn't be able to save yourselves from enquiries, should you?
Ingo Berbig: There is definitely demand. Initially, we are focussing primarily on athletes and not on the broader sales market.
What else do you plan to do with your invention?
Ingo Berbig : We are in the founding phase of a start-up called PI ROPE. Last year, we applied for a patent for the development. In the summer, we will establish a limited company that will continue to be based in Chemnitz. The aim is to have a finished product by the end of the year.
How much will such a bike cost you?
Ingo Berbig: We calculate in sets, i.e. front and rear wheel. That would currently be a four-figure sum - with no upper limit. We don't want to manufacture a mass product, but rather sell products that are characterised by quality simply because they are handmade.
Together with Daniela Storch and Stephanie Mager, Ingo Berbig and Dirk Fischer form the founding team of the research project. "We are currently realising that further support is needed," says Berbig, "for example in design". That's why the team is being expanded.
Do your colleagues come from the world of cycling?
Ingo Berbig: Daniela Storch is a mountain biker. The others cycle a lot as a hobby or simply have to (laughs).
Chemnitz has a long history in the textile industry. Is the TU a leader in this field?
Ingo Berbig : You could say that. Not just nationwide. Since 2006, we have developed a specialism in which we generate research contracts worldwide and, alongside Stuttgart, we are the point of contact for this area.
Is Chemnitz a good place for your start-up?
Ingo Berbig : As we are in the middle of the spin-off process, we can't say yet. The path so far has been good. We have many contacts and people who have already successfully realised this. Many spin-offs from the university have been successful.
Do you work together with companies or sports clubs in Chemnitz?
Ingo Berbig: Yes, we do. As I said, the RSV, which I ride for, has already realised some things that would not have been possible without the club.
Is anyone already riding with your spokes?
Ingo Berbig: No, we can't do that for insurance reasons. Not until the company exists. We are currently still working as a research group. We have a fixed goal. New products are usually presented at certain times. That will be the 'Eurobike' trade fair in Friedrichshafen in autumn.
The German Road Cycling Championships will take place in Chemnitz in June. Are you looking forward to it?
Ingo Berbig: As I'm involved through the club, I'm already looking forward to it. It's great that it's taking place in Chemnitz and we're looking to see to what extent we can integrate ourselves there as a start-up. Basically, it's important for Chemnitz that we have the championship here.
Where do you see yourselves or your company in 2025?
Ingo Berbig : Definitely way ahead. (laughs) When we think about 2025, we'll be the ones in the world who are the contact for textile spokes. We will definitely be well known.