From electronic drivetrains to internal gear hubs designed to withstand the additional torque of mid-drive motors, there is no lack of new drivetrain-related products in the industry. Even better, some of this cutting-edge technology is trickling down to lower-budget price points.
There’s been a lot of media coverage on YouTube of late on made-in-China drivetrains, due to the growing number of Chinese manufacturers switching focus from pure contract manufacturing for the OE market to the more lucrative aftermarket. With this ambition comes the need for branding and increased visibility. So, it’s no surprise to see the likes of L-Twoo, Wheeltop and Magene upping their game and expanding their footprint.
As for the big drivetrain trends, an obvious one is the rise of wireless electronic. Apart from clean looks, the main reason for this are time savings for assemblers and added functionalities for consumers. Most manufacturers of electronic drivetrains offer customization through dedicated apps so consumers can adapt the function of various shift buttons to their preferences. A second big trend is automatic shifting solutions that allow riders to focus on the trail or traffic ahead and braking without having to think about shifting. Most of the automatic drivetrains are built for e-bikes, but not all. Internal gear hubs are also seeing an increase in demand as they work well with mid-drive motors, resulting in durable and sturdy solutions.
The new Di2 electronic mountain bike groupsets from Shimano were likely one of the biggest news items of last year’s Eurobike. Designed as one-by drivetrains, they are built around wide-range cassettes to survive serious abuse in rough conditions. To deflect impacts, the rear derailleur has a low-profile wedged-shape design, with a mechanical mechanism built in to return it to its proper position upon impact. The Shadow+ friction damper has been redesigned to be more compact and require less maintenance. While the long-cage version of the rear derailleur can handle wide-range cassettes with up to 51 teeth, the mid-cage version designed for cross country racing is made for a 45-tooth cog, adding ground clearance while shedding weight.
As for the batteries, Shimano is moving away from a central unit connected to the shifters and derailleur. Instead, a battery with a capacity of 310 mAh has been placed within the linkage of the rear derailleur. There is one specific version of the derailleur for e-bikes that comes with a 12V cable rather than a battery to be powered from the bike’s main battery. The shifter relies on a cell battery and sits well-protected under the handlebar. Its design allows for a wide range of adjustment to fit all hand sizes. Apart from the two shifting buttons, the shifter features a third button that allows for on-trail fine-tuning of the derailleur, another feature that comes in handy after a mid-ride crash.
Two years after a surprise first showing at Eurobike, Shimano brought its Q’Auto technology to the market. This is essentially a Cues Di2 rear derailleur coupled to a special rear hub with an integrated dynamo and sensors to create a derailleur-based electronic drivetrain with no battery and automatic shifting. As for the latter, the system learns with each ride and adapts to the habits of the rider. For this reason, you still get wireless shifting buttons to override the automatic gear selection. Every time you do this, the Q’Auto drivetrain registers this and fine-tunes its behavior so less skilled riders can get the most from modern wide-range drivetrains, be it on urban, trekking or even gravel bikes.
China’s prime drivetrain manufacturer L-Twoo has been expanding its offerings into hydraulic disc brakes and has been gradually electrifying its line-up. After the eRX and more affordable eR9 drivetrains for road bikes, the company followed up with the eGR for gravel bikes and now the eTX as its first electronic drivetrain for mountain bikes. Capable of handling cassettes with up to 46 or 52 teeth, depending on the length of its cage, the rear derailleur of the eTX can be configured by an app to work with cassettes with 10 to 12 speeds. It also comes with a clutch mechanism to keep the chain under tension and from derailing in particularly bumpy terrain. As for the lever, L-Twoo relies on a compact thumb shifter.
With its sturdy, novel 5-speed internal gear hubs, L-Twoo also shows ambitions to enter the OE market for utility bikes. With a total gear ratio of 230 percent, the FX hub has been designed to work with urban e-bikes and with classic bicycle chains and belt drives alike. A four-bolt pattern is used to mount the disc rotor. The electronic version of the new internal gear hub can be tuned to work in sync with an e-drive system and relies on a thumb shift lever, whereas the mechanical version works with a twist shifter. Lastly, L-Twoo is keeping a keen eye on niche markets and therefore developed the eTT groupset. Built around an electronic drivetrain and hydraulic brakes, the eTT has been designed to improve the ergonomics on TT and triathlon bikes.
The big news from Chinese drivetrain maker Wheeltop is the EDS OX 2.0 wireless drivetrain for mountain bikes, consisting of a rear derailleur with an integrated friction damper, a built-in 800mAh battery and an electronic thumb shifter. The latter is powered by a CR2032 cell battery and uses the Bluetooth protocol to connect to and communicate with the derailleur. These components can be combined with disc brakes, cranksets, chains and cassettes of one’s own choice with 10 to 52 teeth when using the longest derailleur cage. Through Wheeltop’s own app, the rear derailleur can be configured to work with 3 to 14 speeds, in an effort to be future-proof.
But it can also be made to work with low-cost 8-speed cassettes, which is a pretty unique feature. The app also comes with a fine-tuning function and the drivetrain can connect to bike computers that use the ANT+ protocol to show the derailleur’s charging status and the gear that’s currently in use. With the existing EDS TX Wireless for road bikes and the EDS GeX Wireless for gravel bikes, Wheeltop already has complete groupsets in its line-up that come with cranksets and hydraulic disc brakes, including 2-piston calipers built to work with the flat-mount standard.
In a quest to bring down the entry-level price point for electronic drivetrains and the added potential to analyze and optimize workouts, Magene set out to develop a full groupset for road bikes. Its vast experience in electronics allowed this Chinese manufacturer to speed up the development of the QED Road Bike Electronic Shifting System. Rather than going wireless, Magene opted for a central battery unit that is connected to the shifters and both the front and rear derailleur. The communication protocol is wireless, however, to allow for connectivity and advanced analysis of workouts. Another interesting feature of the QED Road Bike Electronic Shifting System is its algorithm-based system to compensate for wear of the drivetrain components and keep gear changes both fast and precise. This drivetrain can be combined with cable-actuated rim brakes as well.
built for e-bikes, with longevity in mind.
Specifically designed for the use on e-bikes, the U-Series of Sunrace has consisted of a selection of cassettes and a reinforced chain to date. The cassettes have been engineered to provide increased durability, reduced maintenance and smooth shifting performance. According to Sunrace, they are compatible with Shimano’s CUES drivetrain, relying on Linkglide technology. For 2025, the U-Series is expanding substantially, evolving into a full drivetrain offering. While the U9 drivetrain can shift through nine gears, the US version comes with 10 gears and the top-tier UX version with 11 gears. A damper is built into the rear derailleur, and specifically shaped teeth of the cogs keep the chain safely on track when things get bumpy. For less experienced riders, the dual-lever shifter comes with a simple gear indicator.
Despite some recent ventures into electronic shifting, Microshift is firmly rooted in the value-oriented volume segment. Fittingly, the Taiwanese drivetrain specialist has updated its Estes drivetrain offering for 2025, bringing one-by technology to the entry-level. As for the rear derailleur, there are options with a medium or long cage and versions that can deal with modern wide-range cassettes with 7 to 9 speeds. Microshift builds those with 12-to-40 and 11-to-42 teeth, resulting in what the supplier claims to be the most affordable one-by drivetrain on the market. Additionally, there is one version with a short cage built for kids’ bikes that works with 7-speed cassettes with a reduced range and additional ground clearance. You also get to choose from either thumb or twist shifters to change gears, each with built-in gear indicators.
At last year’s Eurobike, TRP as the premium racing division of Tektro launched the E.A.S.I. A12 electronic drivetrain. Developed in close cooperation with Bosch eBike Systems, this was the first derailleur-based drivetrain fully compatible with Bosch’s eShift technology. Firmly positioned in the premium bracket, the derailleur was designed to work with 12-speed cassettes. At this year’s show, TRP expands the wireless E.A.S.I. A-range to lower price points, adding a 10- and an 11-speed version to its offerings. While the long cage of the E.A.S.I. A11 derailleur can shift cogs with up to 50 teeth, the E.A.S.I. A10 comes with a shorter cage and therefore can only handle cogs with up to 43 teeth.
Due to the high torque levels they dish out, mid-drive motors tend to significantly speed up the wear of drivetrains. One way to address this issue is to resort to internal gear hubs. But most of these have been built with utility bikes in mind—think Shimano’s Nexus series or Enviolo’s stepless 380 hubs. For this reason, German start-up Revolute decided to develop and build an internal gear hub made for harsh off-road conditions. First prototypes of a premium 8-speed hub with disc brake rotor mounts were shown at the Eurobico event in July 2021. Since then, a lot has changed: Revolute has adapted the design of its A8 hub for wireless shifting and added an automatic shifting mode as well.
The eight gears of the A8 hub cover a range of 419 percent, and its internals have been specifically designed to withstand the high torque loads associated with full-support mid-drive motors. According to Revolute, the hub does not require regular maintenance as it’s delivered with a lifetime lubrication using special grease. For value-oriented utility e-bikes, Chinese manufacturer Lofandi has a similar product, with its 5-speed electronic gear hub that can be shifted manually or automatically. Covering a range of 249 percent, the internals of this gear hub have also been designed to withstand high torque loads. Weighing 2.15 kg and built for 36 j-bend spokes, this hub is designed to fit dropouts with a width of 142 mm.
After an initial showing at the Sea Otter Festival, Qo Bike rolled out its full line-up at last year’s Eurobike. Positioned in the premium segment, this Spanish brand focuses on cranks made of carbon, with critical impact protection built into the crankarms. Offered in various lengths, both the Race and the Grava cranksets come with dimpled surfaces for enhanced aerodynamics, while the Rocks mountain bike crankset puts an extra emphasis on impact resistance.
The Crank Gear crankset from South Korean manufacturer Contavelo relies on an integrated planetary transmission rather than a front derailleur to shift between two chainrings. The gear ratio of the planetary transmission mimics the ratio proven on road bikes. Apart from clean looks, this solution also promises to be low on maintenance and lightweight, while keeping a constant chain line