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The most common safety risks that we come across in our daily work around bicycle safety, technology and operating instructions are also published by us in articles in the leading German special-interest magazines TOUR (Europe's road bike magazine no. 1), BIKE (Europe's mountain bike magazine no. 1), MYBIKE and EMTB in order to make this information, which is important for the industry, available to a wider public.

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VCD fairkehr, 2018/02
Reading time 4:30 minutes

“Hands off conversion kits”

A bicycle becomes a pedelec: an interview with the bicycle safety expert Dirk Zedler about risks and side effects of subsequent electrification of bicycles.

fairkehr: Mr Zedler, your advise: Hands off e-bike conversion kits. What can happen?

Dirk Zedler leads Institut für Fahrradtechnik und -Sicherheit GmbH

Dirk Zedler: What can happen if the end consumer buys a kit and screws a motor to his bike, is very simple. The motor increases the load acting on the bicycle components considerably. This is a fact. We know that from load measurements during riding and from failures occurred in practice. Surveys show that customers riding with electric assistance do more distances, in some cases they use their bicycles five times as much. The bicycles without motor are, however, designed for the behaviour prevailing to date. A higher load leads to a higher risk that components such as handlebar, fork or frame break. Another thing is that bicycles that are retrofitted are normally not new: Bicycles older than two to three years were possibly not tested sufficiently for durability. How shall a customer buying a conversion kit know then whether his bicycle will withstand? And there are further questions arising: How long and how much has the customer used his bicycle? Did he take a lot of luggage with him? Perhaps he has already fallen down. The end consumer simply lacks the possibility to check whether his bicycle is suitable to withstand the load with e-motor.

That means that the problem is rather to be seen in the bicycles than in the conversion kits?

Exactly. There is another thing: By electrifying a bicycle, I turn it into an electric machine. Every electric component radiates. Of course, the manufacturers of conversion kits carry out electromagnetic compatibility tests. This test is to check the intensity of radiance and whether there is interference with mobile phones, cars or radio. The following incident occurred: A pedelec rider stopped in front of traffic lights next to a lorry. Suddenly, the pedelec set off just like that. There had been an interference with the lorry’s radiance. As a matter of fact this is pure horror for the cyclist. Meanwhile, serious pedelec manufacturers check every bicycle type as fully assembled bicycle for electromagnetic compatibility (EMC test). Even if the manufacturers of conversion kits test the motor, customers cannot be sure that they will not be concerned by malfunctionings. The bicycle acts like an antenna for electromagnetic radiation. The kit company cannot check whether the overall system e-motor plus bicycle works troublefree.

Who is liable, if the brakes fail or the frame breaks on a retrofitted bicycle.

Most probably not the manufacturer, as the bicycle has been modified considerably. In front of the court they will go on the defensive and try as hard as possible to substantiate that the modification originated the loss. That is to say, liable will be the one who carried out the conversion, the end consumber or the bicycle shop. For this fact alone, we advise: Hands off! And in addition, it does not really pay.

What do you mean by that?

A high-quality conversion kit costs 1,500 Euro at least. Riding with the cheap ones is no fun. That poses the question whether it is not better to buy an additional pedelec that is safe and that makes me choose between an electric bicycle and a normal one. My personal opinion is that you need not take the pedelec for every way. On plane distances you actually do not need one. But it is up to everyone to decide.

In your opinion every conversion into a pedelec constitutes a criminal offence - please do explain that.

For dealers it is actually forbidden by law to convert a bicycle. In Europe, we do have a Product Safety law which is 21 years old. In view of consumer protection this law stipulates extremely severe regulations. It stipulates that a product must not be made availeble, displayed or used for the first time on the market, if it does not fulfil all regulations applicable. A pedelec manufacturer has a lot of expenses to declare the conformity of the product with the requirements. They are for exampled obliged to make a risk analysis and to carry out many tests: mechanical load, EMC and electrical as well as functional safety. Apart from that they have to supply operating instructions in the native language. Serious manufacturers comply with these requirements and therefore pedelecs are more expensive. If all that has been fulfilled, the manufacturer must establish a declaration of conformity and sign. It is only at this stage that they are allowed to put on the CE mark sticker.

Now, a customer with his six year old bicycle asks his retailer to have his bicycle assembled with an electric motor. How shall this retailer fulfil the requirements for the conformity test? He can neither rely upon the past tests of the bicycle manufacturer, as he is not familiar with the history of the six year old bicycle. But legally speaking he is only allowed to modify the bicycle, if he can substantiate that the bicycle withstands the loads. Believing alone does not help.

Nevertheless, there are a few retailers offering the conversion - how come?

Many retailers are unaware that they break the law and thus run the risk of committing an offence. And: With no one as plaintiff, you don’t need a judge. The market surveillance authorities seem to be overcharged. They make their tour to the pedelec manufacturers and make sure that the great majority runs well, there is a lot of catching up. For a long period of time the bicycle industry has not been forced to care about that, because bicycles were leisure articles and sports equipment, no one was interested in that. Due to the e-bike, the bicycle has become part of mobility. With the electric motor the bicycle turns into a machine and is therefore subject to other directives and laws.

Nevertheless, do you see safe conversion solutions for the future?

In the midterm, I do see solutions. Maybe, bicycle manufacturers will implement the idea of launching e-bike ready models on the market and to test the bicycles according to so high criteria that they can grant a conversion into a pedelec with specific conversion kits for example within the first four years. That would actually be a cool thing, legally correct and safe.

Interview: Valeska Zepp
Photo: Zedler


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