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Electronic Shifters & Derailleurs for Road and Mountain Bikes
They shift quickly & precisely: electronic shifters & derailleurs are now used on many high-quality bicycles. An overview of various systems.
On many high-end mountain bikes, road bikes, and gravel bikes, electronic shifting systems now come installed straight from the factory. They are also becoming increasingly popular in custom builds and as upgrades. Most of them now work wirelessly, while others are semi-wireless, using a mix of wireless technology and cable transmission. All of them offer advantages over mechanical groupsets with cables: they shift more precisely and reliably. Here, you’ll learn how the systems differ and why an electronic groupset can be a real alternative for your bike.
Advantages of Electronic Shifting compared to Mechanical Groupsets Easier Installation and Maintenance with Electronic Shifting Simplified Shifting Logic with or without a Front Derailleur Similarities with Mechanical Groupsets Shimano Di2: Overview Shimano Di2: Ergonomics Shimano Di2: Installation and Power Supply SRAM AXS: Overview SRAM AXS: Ergonomics SRAM AXS: Installation and Power Supply Campagnolo Wireless: Overview and Ergonomics Campagnolo Wireless: Installation and Power Supply Electronic Hub Gears Battery Life and Firmware
Electronic shifters and derailleurs provide you with the highest level of shifting precision at the push of a button.
The front and rear derailleurs receive signals from the shift levers via cable or wireless transmission.
By eliminating maintenance, you save valuable time that you can rather spend riding your bike!
Advantages of Electronic Shifting compared to Mechanical Groupsets
The most obvious advantage of electronic shifting: you no longer have to deal with cable housings. This makes many things easier – installation, adjustment, maintenance and wear. Cables or wireless connections don’t need constant readjustment or regular replacement. Once set up, they deliver consistent shifting precision. Shifting is done via buttons: they don’t require long lever travel, demand little hand force, and their mechanism doesn’t wear out due to dirt. Motors in the rear derailleur and front derailleur do the main work – always equally fast and strong. Optional extensions allow you to shift from other handlebar positions too, for example from the tops or aerobars of your road bike. Of course, electronic systems also offer connectivity. They can communicate with your cycling computer or with apps on your smartphone. The added value ranges from simplified button configuration, through real-time information, to detailed analysis of collected data. Connected devices also help you monitor the charge status of your batteries and remind you to recharge in time – because without power, the derailleur motors won’t move.
Really smart: easy configuration and customisation via app. © bc GmbH
Easier Installation and Maintenance with Electronic Shifting
A basic distinction is made between fully wireless systems, semi-wireless systems (a mix of wireless and cables) and fully wired systems. Fully wireless drivetrains are extremely easy to install and make for a very clean bike. Your frame doesn’t need any internal cable routing. You simply bolt the rear derailleur and front derailleur (if needed) onto the frame, attach the shifters to the handlebar, and pair the wireless connection.
A semi-wireless system works with a wireless connection between brake-shift levers and rear derailleur, and a cable connection between the rear derailleur, front derailleur and central battery. The rear derailleur serves as the brain of the group, receiving and processing the shifting signals and transmitting them by cable to the front derailleur. Installation is a bit more complex than with wireless, but still much easier than with internally routed cable housings. The e-cables are thinner and more flexible and, unlike cable housings, do not need regular replacement – so routing them is usually a one-time job.
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Simplified Shifting Logic with or without a Front Derailleur
On groups with multiple chainrings, the electronically controlled front derailleur can take chainline into account – that is, the current position of the chain on the cassette. For example, if your chain is on a large sprocket, the derailleur cage doesn’t need to move as far when shifting from the large to the small chainring, compared to when it sits further right on a small sprocket. This effectively prevents overshifting. You can also let the intelligent electronics decide when the front chainring is shifted: you then just shift up or down, without thinking about whether the front or rear derailleur (or both) need to move. When you manually switch chainrings, the rear derailleur can automatically counter-shift a few sprockets so the gear jump is not too big. If you prefer full control, you can of course shift completely manually. Even with single-chainring setups, you benefit from the improved shifting logic that prevents overshifting on the cassette or allows multiple gear jumps at once when needed.
Electronically controlled front derailleurs take the chainline into account so that your chain always runs smoothly. © bc GmbH
Similarities with Mechanical Groupsets
There are several aspects you need to consider when buying a groupset or upgrade kit: number of gears and gear range, compatibility and installation dimensions (especially if you choose a SRAM group), scope of delivery and brakes. These apply equally to both electronic and mechanical groupsets. You’ll find more information about this in our general articles on MTB, gravel and road bike groupsets.
Shimano Di2: Overview of All Groups for MTB, Road & Gravel
Shimano's electronic shifting system has been on the market longer than all others and is known for its high shifting speeds. Di2 stands for “Digital Integrated Intelligence”.
Earlier Di2 groups were semi-wireless, but in summer 2025 Shimano introduced new fully wireless groups.
Depending on bike type, the following are available:
| Wheel Type | Group | Gearing | Transmission | Mount Type | Release |
| MTB | XTR Di2 M9200 XT Di2 M8200 Deore Di2 M6200 | 1 x 12 | wireless | Conventional (derailleur hanger, UDH) | 2025 |
| E-MTB | XTR Di2 M9200 XT Di2 M8200 Deore Di2 M6200 | 1 x 12 | wireless | Conventional (derailleur hanger, UDH) | 2025 |
| Road Bike | Dura Ace Di2 R9200 Ultegra Di2 R8100 105 Di2 R7100 | 2 x 12 | semi-wireless | Conventional (derailleur hanger, UDH) | 2021 2021 2022 |
| Gravel | GRX Di2 RX827 GRX Di2 RX825 | 1 x 12 | wireless semi-wireless | Conventional (derailleur hanger, UDH) | 2025 2024 |
Note for E-MTB: Shimano’s new E-MTB derailleurs combined with EP8 or EP6 motors create an optimally tuned system with smart features such as automatic shifting.
Note on Shimano CUES Di2: Designed for urban e-bikes, this system offers automatic shifting and has already been used in other categories. Together with Shimano’s Q’AUTO system (introduced in 2025), CUES Di2 now also brings automatic shifting to non-motorised urban and gravel bikes. Power comes from a dynamo hub – no battery required. For high-performance sports use, however, we recommend one of the groups listed above.
Shimano Di2: Ergonomics
The default button layout is based on mechanical shifters: two buttons, one for upshifting, one for downshifting. On MTBs, the buttons sit under the handlebar. On road bikes, they are directly behind the brake lever. No combined brake/shift lever movement – energy saved! With an additional button on the brifter, you can scroll through menus on your compatible cycling computer.
Through the E-Tube Project app, every button (including add-ons) can be freely configured. You can also adjust shift speed, the number of gears shifted when holding the button, and front derailleur shift modes.
Shimano offers three different Di2 shift modes: "Synchronised", "Semi-Synchro" and "Manual". © bc GmbH
Shimano Di2: Installation and Power Supply
With Shimano’s new wireless Di2 (introduced summer 2025), everything is cable-free. The battery sits inside the rear derailleur.
The derailleur features a status LED for battery level and current shift mode, an adjustment button for selecting modes, and on semi-wireless systems, a charging port. It also handles communication with the E-Tube Project app and pairing with external devices such as training computers.
To retrofit wireless Di2 to your MTB or gravel bike, mount the components, pair the STI levers with the derailleur – done. For semi-wireless, route two cables (battery–rear derailleur, battery–front derailleur) inside the frame and mount the battery in the seatpost or a frame mount. Pair the levers with the derailleur and you’re ready to ride.
Since the launch of the new Shimano Ultegra and Dura-Ace groupsets, the cable connection shown here, including the junction box, has been omitted from newer models. © bc GmbH
SRAM AXS: Overview of All Groups for MTB, Road & Gravel
With AXS (pronounced “access”), SRAM went fully wireless from the beginning. That remains the case today: all SRAM AXS groups transmit signals wirelessly. The only exception is with e-MTBs, where the Eagle Transmission derailleur in a Powertrain system is usually connected to the main battery.
| Wheel Type | Groupset | Group | Gearing | Transmission | Mount-Type | Release |
| MTB | Eagle Transmission | XX SL XX X0 GX | 1 × 12 | wireless | Full-Mount (UDH) | 2023 |
| MTB | Eagle AXS Drivetrain | XX1 X01 GX | 1 × 12 | wireless | Conventional (derailleur hanger, UDH) | 2019 2019 2021 |
| E-MTB | Eagle Powertrain with Eagle Transmission | XX XO GX | 1 × 12 | wireless or semi-wireless | Full Mount (UDH) | 2023 |
| Road Bike | - | RED AXS Force AXS Rival AXS | 2 × 12 | wireless | Conventional (derailleur hanger, UDH) | 2024 2025 2025 |
| Road Bike | Aero chainring | RED AXS Force AXS Rival AXS | 1 × 12 | wireless | Conventional (derailleur hanger, UDH) | 2024 2025 2025 |
| Gravel | - | Apex AXS | 1 × 12 | wireless | Conventional (derailleur hanger, UDH) | 2023 |
| Gravel | XPLR | RED XPLR AXS Force XPLR AXS Rival XPLR AXS | 1 × 13 | wireless | Full-Mount (UDH) | 2024 2025 2025 |
Aufgepasst beim Gravelbike: Die Zwölf-Gang-Komponenten der AXS-Familie sind untereinander kompatibel und Du kannst sie am Gravelbike zum sogenannten Mullet-Antrieb kombinieren. Das heißt, Du kannst ein MTB-Eagle-Schaltwerk mit breit übersetzter Eagle-Kassette verbauen und mit den Bremsschalthebeln Deines Rennlenkers ansteuern. Elf-, Zwölf- und 13-Gang-Komponenten sind nicht miteinander kompatibel.
Aufgepasst beim E-MTB: Bei der Eagle-Powertrain-Serie sind der Motor und das Eagle-Transmission-Schaltwerk optimal aufeinander abgestimmt. Du kannst Funktionen wie zum Beispiel automatisches Schalten nutzen. Hat Dein Rad ab Werk keine Eagle-Transmission, ist das System mit einem Kit für Bosch, Brose und verschiedene andere Antriebseinheiten z. B. von Shimano oder Panasonic nachrüstbar – vorausgesetzt, Dein Rahmen ist für ein Full-Mount-Schaltwerk (UDH) geeignet.
Aufgepasst beim Nachrüsten eines Full-Mount-Systems: Um ein Full-Mount-Schaltwerk an Deinem Rad nachzurüsten, muss Dein Bike für die UDH (Universalschaltauge)-Spezifikation von SRAM ausgelegt sein und alle erforderlichen Abstände aufweisen. Denn die Full-Mount-Systeme werden anders als die konventionellen Systeme direkt am Rahmen montiert, also ohne Schaltauge oder UDH. Dadurch profitierst Du von einer verbesserten Schaltpräzision, denn Einstellungsfehler und verbogene Schaltaugen gehören hier der Vergangenheit an. Wie das geht? Durch den Wegfall des Radmodell-spezifischen Schaltauges ist die Position des Schaltwerks zur Kassette sichergestellt und so benötigt Dein Schaltwerk weder Einstellschrauben für die Umschlingung (B-Screw) noch den oberen und unteren Anschlag. Und die Full-Mount-Schaltwerke sind laut SRAM so robust und mit einem Ausweichmechanismus ausgestattet, dass Du bei einem Sturz keine Angst um Deinen Rahmen haben musst.
SRAM AXS: Ergonomics
SRAM’s electronic groups for mountain bikes come, depending on group and price level, with a specific controller for up- and downshifting. It is standard for the right-hand side of the handlebar. If your bike is equipped with the also wireless RockShox Reverb AXS dropper seatpost, a RockShox Flight Attendant suspension system and/or an e-MTB with SRAM Powertrain, then an additional controller with one or two buttons is mounted on the left-hand side. The key point: all SRAM AXS shifters and components are mutually compatible. You can customise the shifter functions via the AXS app to suit your preferences.
The brake-shift levers of the road groups each have one button per side. One hand shifts up, the other down – some groups feature bonus buttons on the inside of the hoods. Using the AXS app, you can change the button functions, set how the front derailleur shifts, or adjust how many gears your AXS system shifts when you hold down a button. With optional wired or wireless auxiliary switches, the system can be expanded to allow shifting, for example, from the tops or aerobars of your road bike. For your triathlon or time trial machine, Zipp offers the Vuka Shift AXS aero extensions.
The SRAM Controller shift lever triggers the shifting process electronically thanks to AXS technology. © bc GmbH
SRAM AXS: Installation and Power Supply
Since the shifting components communicate wirelessly, AXS groups are very easy to install on MTB, road and gravel bikes. Your bike requires no cable routing at all. SRAM’s shifters are powered by durable button cells, while the rear derailleur and front derailleur each use a rechargeable battery. These batteries can be removed for charging and are interchangeable between components. Coloured LEDs on the components help you keep track of the charge level and remind you when to recharge. A paired smartphone or cycling computer provides even more detailed information.
In the free AXS app you can manage not only your shifting modes and button assignments, but an entire ecosystem of AXS-enabled components from SRAM, Quarq, RockShox and Zipp in one place. The web-based AXS Web tool also lets you combine all of this with ride data from different cycling computers.
Campagnolo Wireless: Overview of All Road Groups
Campagnolo’s thumb shifter was iconic – and polarising. With the update of the electronic, wireless top-end road group Super Record, it has returned! Here’s a brief overview:
| Radtyp | Gruppe | Schaltstufen | Signalübertragung | Mount-Type | Erscheinung |
| Road | Super Record 13 | 2 x 13 | wireless | conventional mount (derailleur hanger, UDH or Campagnolo Direct Mount) | 2025 |
| Rennrad | Super Record Wireless | 2 x 12 | wireless | conventional mount (derailleur hanger, UDH or Campagnolo Direct Mount) | 2023 |
Campagnolo Wireless: Ergonomics
On the Super Record 13, shifting up and down is done using the thumb shifter and a lever located behind the brake lever. In addition, there is a supplementary button on the inside of each hood, which can also be assigned a shifting function or used to control your Bluetooth-connected cycling computer.
With the MyCampy 3.0 smartphone app, you can read out data, check battery status and customise the shifter ergonomics individually. You can select different shifting modes with alternative button assignments, and even configure the system for one-handed operation.
Campagnolo offers three preset shift modes, "Race", "Comfort" and "Sport", with which you can adjust how crisply the front and rear derailleurs change gears. © bc GmbH
Campagnolo Wireless: Installation and Power Supply
Since the components of the wireless system communicate via Bluetooth, installation is quick and straightforward. You connect the shifters, rear derailleur and front derailleur via Bluetooth – and you’re done. The Campagnolo Ergopower brake-shift levers are powered by button cells, while the rear and front derailleurs use rechargeable batteries. These batteries have magnetic charging ports and can either remain on the bike during charging or be removed and charged with a separate charger. Integrated LED indicators on the batteries and hoods show the current charge status. Note that the batteries for front and rear derailleur are not identical, so they cannot be swapped during a ride if one runs low.
Electronic Hub Gears by Shimano, Pinion & Rohloff
In addition to electronically controlled derailleur systems, there are also electronically controlled hub gear systems. Shimano’s Alfine hub gear for everyday, trekking and touring bikes is available in eight- and eleven-speed Di2 versions. As with the derailleur systems, the hub is controlled via distributors and powered by a central battery. Pinion offers the Smart.Shift system, an electronic central gearbox. Smart.Shift is mainly found on e-bikes, but with the Smart.Shift battery pack you can retrofit most analogue Pinion mountain bikes and some Pinion gravel bikes. Rohloff offers the E-14 electronically controlled gear hub. As this system cannot be retrofitted with its own power supply, it is currently only available on e-bikes. All these systems can be customised to your needs via their respective apps.
Battery Life and Firmware
Battery life varies greatly between groups and depends heavily on shifting behaviour, so we won’t provide precise figures here. Check the manufacturer’s specifications for your chosen group to get an idea of how long one charge will last. In addition to accurate battery status displays, the manufacturers’ apps usually also allow you to update your shifting firmware. Occasionally, new options for button ergonomics are added, or compatibility with newer generations of cycling computers is provided through updates.
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