Medienberichte und Publikationen rund um Fahrräder, Pedelecs, Technik und Sicherheit

Die häufigsten Sicherheitsrisiken, die uns in der täglichen Arbeit rund um Fahrrad-Sicherheit, -Technik und -Bedienungsanleitungen auffallen, publizieren wir auch in Artikeln in den führenden Fachmagazinen TOUR – Europas Rennrad-Magazin Nr. 1, BIKE – Das Mountainbike Magazin Europas Nr. 1 und E-Bike – Das Pedelec-Magazin, um diese für die Branche wichtigen Informationen einer größeren Öffentlichkeit zugänglich zu machen.

Auch die Eurobike Show Daily, Messezeitschrift der jährlich stattfindenden Eurobike Show, gibt uns seit vielen Jahren die Möglichkeit, unsere Sicht auf wichtige Entwicklungen in der Fahrradbranche in ganzseitigen Artikeln auszuführen.

Darüber hinaus sprechen wir regelmäßig in unabhängigen Fachvorträgen über alle Bereiche der Fahrradtechnik und des Fahrradmarktes. Auch weitere Fach- bzw. Branchenzeitschriften sowie immer häufiger Radio und Fernsehen zitieren uns in ihren Medienberichten und zeigen uns, dass wir mit unseren Hinweisen genau richtig liegen. In der Rubrik AKTUELL erfahren Sie laufend alle Neuigkeiten aus unseren Fachbereichen. Diese Berichte und Publikationen sortieren wir für Sie chronologisch bzw. nach Interessensgebieten.

MYBIKE, 2021/03
Reading time 1.75 minutes

Measuring the frame stiffness

On our pneumatically operated ECS test stand (“E-Bike Centre-Stiffness”, Zedler-Institute, www.zedler.de) the test bikes are mounted ready to ride, however, without wheels at the drop-outs of frame and fork. Via form-fitting adapters the test stand takes hold of both ends of the crank axle and pulls the bottom bracket area with a defined force to the side, alternately to the right and left from the centre axle. The determined deflection of partly several centimetres is measured and recorded. The values measured in Newton per millimetre (N/mm) document the side stiffness of the respective frame fork system.

Values from 80 N/mmm are currently rated with sub-rating 1 in the category riding safety. Below this value, the rating deteriorates by one grade every 5 Newtons. Handlebars, stem, saddle, seat post and in particular the pannier rack cannot be included in the measurement. Therefore, the final rating of the test bike is always closely connected to the personal feeling during the ride gained through intensive test rides with and without luggage.

Interview

Graduate engineer Dirk Zedler - publicly appointed and sworn in expert for bicycles and electric bicycles

MYBIKE: What are the pitfalls of a low step-through frame compared to a diamond frame?
Similar to a timber-framework the centuries-old principle is a lucky find. Every frame tube omitted reduces the riding stability. In the case of a low step-through frame the front frame area can move more easily compared to the rear area. Designers must give much more thought to stiffness and durability.

Are there differences between classic bicycles and electric-assisted bikes?
Electric-assisted bikes are equipped with heavier components, cyclists take more luggage with them and the drive unit brings more cyclists in hilly terrain at faster rides. Users of electric-assisted bikes also prefer an upright position on the bike. The requirements are therefore significantly higher with electric-assisted bikes. A battery mounted to the pannier rack is therefore extremely questionable. With a battery mounted to the central or down tube, behind or in front of the seat tube, the electric-assisted bike rides clearly better.

How is frame stiffness related to headtube wobbling?
This can be demonstrated with the intube batteries of low step-through frames: Some manufacturers only cut open the tube to integrate the battery. The down tube offers then hardly any torsional resistance. Even if everything else fits, there is a certain uneasiness of the chassis at low speeds already. Handlebar wobbling as a phenomenon, but also the dangerous riding instability when riding downhill, for example when changing the direction, are not only irritating, but also result in accidents.

How can I be sure when buying a bicycle that my desired bike with low step-through entry also offers sufficient riding safety?
The method “looking closely” is not enough. However, MYBIKE tests in which the riding stability is measured and rated during test rides help a lot. In addition, I can only advise to go on a long test ride with an adjusted seating position and definitely with luggage. It is especially the latter that sorts the wheat from the chaff.

Author: Jochen Donner
Photo: Daniel Simon


If you want to read the entire article, order the respective issue from Delius Klasing Verlag online.

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