Zedler – Institut für Fahrradtechnik und -Sicherheit GmbH, based in Ludwigsburg, is part of the Zedler Group and has specialised in the development and manufacture of testing systems for bicycles and e-bikes since 1994. In the company’s own test laboratory, bicycles and components such as frames, handlebars, saddles and luggage racks are tested for structural integrity – both on behalf of manufacturers and retailers for prototype testing, and for insurance companies and courts as part of expert reports following accidents or damage.
In addition to conducting tests, the company develops and manufactures its own testing machines, which are used in the test laboratories of leading bicycle manufacturers worldwide. In addition, the institute produces standard-compliant operating instructions and manuals for bicycles and e-bikes. With four dynamic laboratories and around 50 fatigue testing systems, as well as a consistently sustainable corporate approach, Zedler GmbH is now regarded as a globally recognised partner for quality and safety in bicycle technology. “We are a classic ‘hidden champion’ with customers from all over the world, although we are primarily known in the bicycle industry,” explains Dirk Zedler, founder, testing expert and consultant at the Zedler-Institut.
Not all bicycles are the same – requirements for testing systems
Bicycles and e-bikes are constantly on the move, often every day and over varying terrain. Bicycle frames range from very compact folding bikes with 16-inch wheels to cargo bikes with a wheelbase of up to 2.15 metres and different-sized front and rear wheels, right through to tandems for two riders. What’s more:
- City bikes often have a low bottom bracket so that you can comfortably put your feet on the ground when stopping at traffic lights.
- Mountain bikes (e.g. enduro bikes), on the other hand, need plenty of ground clearance so that the pedals don’t hit the ground so easily off-road, even when the suspension compresses.
In order to accurately replicate different geometries, wheelbases and bottom bracket heights, test systems must therefore be highly adjustable whilst also being very rigid and capable of withstanding long-term loads, as they are designed to apply precise forces to a wide variety of bicycle frames over many years.
Bespoke testing technology of the highest standard
To ensure that a frame can withstand these constant stresses over many years, there is a standard test in bicycle engineering: the ‘Bottom Bracket Fatigue’ (BBF) test. The bottom bracket is one of the most heavily stressed areas on a bicycle and the point where the pedals are connected to the frame via the cranks. With every pedal stroke, alternating torques, bending and torsional forces are generated, which accumulate over time. Without sufficient stability, cracks could form, ultimately leading to fractures or failure.
In his test laboratory, Zedler simulates the forces generated by a person pedalling, known as ‘pedalling forces’. In the process, the bicycle frame, with the bottom bracket fitted, is repeatedly subjected to artificial stress. This allows him to determine how many of these load cycles it can withstand before the first signs of damage – such as hairline cracks, creaking or play in the bearing – appear. The BBF system developed by Zedler stands out here due to its exceptional adaptability to different types of bicycle and its durable construction. Once all parameters have been adjusted, the test system reproduces the pedalling load that a rider imparts to the frame over the course of the bicycle’s lifetime within approximately 24 hours.
The Zedler-Institut works exclusively with test systems developed in-house, such as the ‘Performance’ test machines. These measure both vehicle handling characteristics and the properties of individual components, providing reliable results on driving stability, safety and comfort under comparable conditions. They also enable conclusions to be drawn regarding the consistently high quality of a production batch.
Powerful machines, reliable components
When building test machines, Zedler does not rely solely on its in-house expertise, but also places its trust in partners such as Norelem and its extensive range of standard and control components for mechanical and plant engineering; in other words, this is where Zedler finds a wealth of ideas and solutions that continue to inspire it.
Norelem is an internationally active company based in Markgröningen near Stuttgart, which has been supplying high-quality standard components and system solutions for mechanical and plant engineering for over 60 years. The product range now comprises more than 130,000 standard and control components, including aluminium profiles, joints, control elements and clamping technology, as well as measurement and testing technology. Free CAD data, a user-friendly online shop and high parts availability round off the offering.
Norelem components are regularly used in the construction of Zedler testing machines, as company founder Dirk Zedler explains: “We started out very small and initially ordered clamping levers from Norelem – a classic item from their standard parts range. And now we’re using more and more of them, including entire systems such as linear guides with the corresponding brakes.” The custom-made testing machines are thus created through an “intelligent combination of Norelem profile guide rails, guide carriages, clamping elements for profile guide rails, special components manufactured by us, profiles and accessories from a leading aluminium profile manufacturer, and Norelem small parts, such as clamping levers, various types of joint heads, fitting screws and more.” At Zedler, it has been found that the use of Norelem standard parts significantly extends the service life of the testing machines and achieves greater precision. Consequently, the test results also become increasingly accurate and reliable.
No signs of fatigue: How to keep getting better
When you enter the Zedler-Institut, you inevitably find yourself on what is known as the ‘Walk of Fail’: a 30-metre-long row of broken bicycle components – parts that did not fail on the test machines, but out in the field, on the road or off-road. “And that is precisely what we learn from,” explains Dirk Zedler, “so that we can make our test machines and test procedures even more robust and continue to improve them.” For 15 years now, the company has relied on its partnership with Norelem: “We have been working with Norelem for so long precisely because their wide range of products allows us to continually find new approaches with which to optimise our systems.”
The collaboration goes far beyond simply supplying components. What Zedler particularly values about the standard parts experts is “their reliability, on-time delivery and the whole package. In our consultancy division for the bicycle industry, we’ve had some less than positive experiences with parts sourced from online marketplaces. That’s why we deliberately avoid such sources and rely on the reliability and quality of Norelem.”
And the enthusiasm is palpable on the supplier’s side too. “Working with the Zedler team is something special for us,” emphasises Dirk Langenohl, Key Account Manager at Norelem. “It is inspiring to see how our standard parts are used in highly complex testing machines – and how this ultimately results in a little more safety for cyclists all over the world.”
Both companies are in no doubt that their collaboration will continue. Zedler is growing steadily, constantly developing new testing systems and supporting an increasing number of manufacturers. “Every time we build a new system, we discover something new within the portfolio – and that in turn inspires us in other areas. This is how our partnership with Norelem is becoming ever closer,” says Dirk Zedler, looking to the future.
AboutNorelem
Norelem supports designers and engineers in the mechanical and plant engineering sector with standardised components to help them realise their design solutions. Over 130,000 standard and custom parts are immediately available in the user-friendly online shop, including free CAD data for faster design without the need for drawings or configuration. Through the ‘Norelem ACADEMY’, Norelem is also committed to promoting young talent and offers technical training courses, seminars and product training.
