FFor many cyclists – in this case actually mostly male – it is a matter of course to maintain and repair their vehicle in person. The technology of the bicycle seems simple: While you can no longer even replace a defective headlight on a car, maintenance and repair work on the bicycle can be done with few special tools and without training as a mechatronics engineer. That has changed slightly in recent years: not everyone will bleed their disc brakes themselves or change the oil on their Pinion gearbox or a Rohloff hub.
From self-help as the norm, it is only one step to work that modifies the bike. Upgrading and retrofitting up to the conversion are only limited by the technical possibilities, the know-how and the personal skills. No cock crows when I turn a half-burner from a flea market into a single-speed car on thumb-width tires for city traffic. I just have to know how to implement the right chain line and which gear ratio fits. And of course I am responsible for ensuring that my tinkering meets the requirements for participation in public road traffic.
Everything that has been said so far only applies as long as the bicycle does not have an auxiliary electric motor. A lot is very different with the pedelec. First of all, the percentage of users who bring their vehicle to the specialist workshop for service, as they are used to with their car, increases significantly. A wrench flashes continuously in the display of the motor control unit, the instructions given when you buy it await the maintenance stamp on the back as a checkbook, the purchase price of the electric bike suggests that maintenance is recommended. The fact that there are reckless people who prefer to use the means of chip tuning to tease out more speed than what is allowed is completely ignored here. What is forbidden is made more difficult for them by current engine versions; Tuning kits, however, are freely available in online shops and are installed at home. This often goes undetected, but in the event of an accident it can turn out to be a nasty liability boomerang.
Even if you only want to replace wear parts of the pedelec and have no tuning in mind, you need to be careful: tires, for example, should not only correspond to the original equipment in terms of their dimensions, but should also be expressly approved by the manufacturer for the loads caused by a pedelec or S-Pedelec to be marked. It is obvious that any replacement of the components of the electric drive up to and including the charger is not permitted because the bike loses its CE conformity. You should always use original parts or parts that have been declared suitable for the intended use by the manufacturer of the bike and / or the components.
Some things seem contradictory at first glance: For example, bags or a topcase are not regulated in more detail at the back, but approval by the vehicle manufacturer is required for a handlebar basket. And sometimes the devil is in the details. Replacing a battery light with a K number is completely unproblematic, but not replacing a headlight attached to the motor battery: It can disrupt electromagnetic compatibility.
In detail, a guide that was developed jointly by industry associations and testing institutes provides an overview. It lists in five categories which parts (for example: pedals, stands, handles, but also gears or chainrings, belt pulley or sprocket) can be exchanged and for which other special requirements apply. The handout can be found online at the Zedler testing institute, for example.