Electronic vs. mechanical groupsets

On traditional bikes (e.g. road bikes) a “groupset” includes all components for shifting and braking: shift levers, brakes, crankset, chainrings, cassette, chain, rear derailleur and front derailleur. Shimano and SRAM supply these as a perfectly matched package.

On e-bikes, things can look different:

• With Shimano or SRAM, you still get the usual combination of drivetrain and brakes – the motor is a separate system.
• With Pinion E-Drive, the electronic gearbox is integrated directly into the motor unit – brakes come from another manufacturer (e.g. Magura).

In general: the higher the quality of the drivetrain, the more precise and faster the gear changes, the longer the components last – and often the lighter the overall weight. Electronic systems add extra features such as app connectivity, customisable shifting logic and often reduced maintenance.

Mechanical shifting

Still widely used on MTBs and trekking bikes – but on road bikes now mostly limited to the entry-level segment – is mechanical shifting. It works via thin Bowden cables that connect the shift levers to the front derailleur (up front) and rear derailleur (at the back).
When you operate the shift lever, the cable is shortened or lengthened by a set amount. This moves the front derailleur to shift the chain onto a different chainring, or the rear derailleur to shift it onto a different sprocket.
On SIMPLON bikes, cables are often fully routed inside the frame – protecting them from dirt and giving the bike a clean look.

Electronic shifting

Here, electrical signals replace Bowden cables. Nowadays, the shift signal is transmitted wirelessly at both SRAM and Shimano. Only one cable remains in Shimano systems: it runs from the rear derailleur through the chainstay to the front derailleur, supplying both components with power from the central battery and also serving to charge the entire system. Small electric motors precisely move the chain – or, in the case of belt drives, the gearbox components.
Power comes from integrated batteries – depending on the system, either one per derailleur or a central battery for the whole setup. Advantages include no cable wear, precise shifting even under load, and often customisable settings via an app.

Integrated gearbox shifting (e.g. Pinion E-Drive)

On some e-MTBs and trekking bikes, the shifting mechanism is built directly into the motor housing – as with the Pinion E-Drive. This electronically controlled, sealed multi-speed gearbox is often paired with a low-maintenance belt drive.
Shifting is done at the push of a button, even while stationary. Bowden cables and external derailleurs are eliminated entirely – the system is protected from dirt, impacts and stone chips.

Electronic drivetrains are on-trend – and not just for road bikes. Gravel bikes, e-mountain bikes, and trekking bikes also benefit from their precise, comfortable technology. Whether it’s Shimano Di2, SRAM eTap AXS, or an integrated gearbox like the Pinion E-Drive, gear changes happen at the push of a button or via wireless signal – fast, quiet, and reliable.

Advantages

A key benefit is the high shifting comfort. Just a light tap is enough to change gears – with no effort required. This is especially pleasant on long rides, climbs, or when your hands are tired. Many systems allow shifting from different handlebar positions, adding both comfort and safety.

When it comes to precision, electronic systems clearly have the edge. A small motor ensures the chain or gearbox is always perfectly aligned – no manual fine-tuning needed. Even under heavy load, such as during climbs or sprints, gear changes remain smooth and quick. With integrated gearboxes like Pinion, the mechanism is also protected from dirt, rock strikes, and weather – and can even be shifted while stationary.

Aesthetics also benefit: visible shift cables are eliminated, with wiring routed internally or gone entirely on wireless systems like SRAM AXS. This results in a clean look and reduces maintenance, as there are no cables to wear out or seize up.

Disadvantages

Electronic systems are more expensive to buy than mechanical ones and are usually slightly heavier. They also depend on a battery, which must be charged regularly. In practice, however, a single charge often lasts for many thousands of shifts, and most systems make it easy to check the battery level.