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Retrofit kits for e-bikes

E-bikes are not cheap. It is therefore tempting to convert the own bike into an electric bike on your own with an inexpensive retrofit kit. Nevertheless, experts and the German Cycling Association (ADFC) advise in general against conversion.

With the booming e-bike business, the trade in retrofit kits that can be used to convert conventional into electric bicycles has also established itself in recent years.

Retrofit kits can cost significantly less than complete e-bikes. Especially, when the basis consists of a high-value bike, you would have to dig deep into your pockets for an equivalent electric bike. Anyone who has already invested a lot of time and money in customising a bike to his personal needs will be reluctant to give it up.

Experts advise against conversion

Nevertheless, experts and the German Cycling Association (ADFC) advise in general against conversion. Reason: A bike that has not been designed to withstand the loads of an electric motor can become a safety risk.

The construction of the frame, the fork and the add-on parts are not designed for the additional loads. “We therefore strongly recommend: hands off retrofit kits. There is a high risk of failure with unforeseeable consequences”, says bicycle expert Dirk Zedler from the institute for bicycle technology and safety.

The additional load consists of several kilograms of extra weight of the motor and electronics, higher loads due to faster starting, possibly a higher average speed which puts more stress on the parts.

Longer service life

The range of use of the converted bikes often changes and they are used more frequently: According to Dirk Zedler, thanks to the motor a bike that would not have caused any problems in low-land areas is now also used in the mountains and has to withstand much higher loads.

It is not possible to tell whether a bicycle can withstand these loads simply by looking at it from above. No dealer can reliably judge whether the bike in question is likely to withstand the additional loads or not, even if manufacturers of retrofit kits like to suggest that it can. Even a bicycle without superficial damage may already be affected by previous damage.

Legal pitfalls

Anyone who converts a bicycle into an e-bike on his own, will lose all warranty claims. For bicycle dealers who install retrofit kits the situation is difficult: They legally become the manufacturer of a completely new vehicle and are fully liable. Although one supplier of retrofit kits insures dealers against this risk, this is of little benefit to customers when a component fails.

Only a few manufacturers offer retrofitting on their own initiative, such as Utopia Velo, but they first put the bike through its paces before converting it. Anyone who doesnt’s have this option, should better buy a new electric bike.