Some software updates slip by unnoticed. Others transform your ride entirely. Over the past few months, a new trend has emerged: e-bike motor manufacturers are releasing digital upgrades to squeeze more performance out of existing systems. Instead of reaching for the toolbox, performance now comes from the cloud. MAHLE are the latest to join the fray with a digital turbo for their rear hub motor. The X20 is getting a virtual power boost – and we’re here to tell you whether it delivers, and how to get your hands on it.
This firmware update marks the next evolutionary step for a motor that’s already known as one of the lightest and least obtrusive drive units out there – now with added bite. And it’s not just the software that’s been tweaked. The latest X20 units are now compatible with SRAM’s UDH standard, paving the way for e-gravel bikes with cutting-edge drivetrain systems.
Development and testing all happen in Palencia, right in the heart of northern Spain. That’s where MAHLE took over the start-up Ebikemotion back in 2018 – and where around 50 engineers are now working on the future of lightweight e-drives. Custom-built test rigs are used to put the motors through extreme heat, cold, moisture and long-term strain. We already visited the MAHLE SmartBike Systems R&D department back in 2023 and took a close look behind the scenes.
Even back then, it was clear: this isn’t just about hardware. When there’s a ‘Smart’ suffix in the name, you need clever software to elevate a simple drive system to the next level. MAHLE’s Smart Assist mode is a great example, using a wide range of data inputs – route length, heart rate, gradient, battery level and rider power – to fine-tune support and adapt to the rider’s needs.
A closer look at the X20 upgrade – More oomph from the cloud
Tipping the scales at just 1.39 kg, the X20 motor has already helped several bike manufacturers build sporty e-road and e-gravel bikes that feel more like an analogue bike with a gentle breeze of tailwind than a bulky e-bike. We’ve already tested it in models like the Mondraker Dusty XR, BMC Roadmachine AMP ONE and ROSE REVEAL PLUS, pushing the X20 to its limits both on the road and off it.
What stood out was its natural ride feel, subtle assistance and low system weight. But there’s a fundamental difference between hub motors and mid-drive units: hub motors deliver their power directly to the rear wheel rather than through the drivetrain. We’ve already taken a deep dive into how that impacts performance and cleared up some common myths around the topic.
That direct power delivery has a cascading impact on the way torque figures are understood. Before the update, the X20 delivered a maximum of just 23 Nm on paper. But since it bypasses the gears and acts directly on the rear wheel, MAHLE say that it feels more like a 55 Nm mid-drive motor. Or rather, now, like a 65 Nm motor. Because according to MAHLE, the new firmware increases torque by a hefty 18%. In real-world terms, that means more punch when setting off, more power on steep climbs and a smoother, more confident delivery of force.
Peak power has gone up too: from 250 watts to 275 watts – an increase of around 10%. Upping your personal peak power by 10% would take serious training. The X20’s built-in power meter reads your own output and adds up to 200% on top, depending on the support level.
What’s especially interesting is that MAHLE managed this performance boost without changing the housing or adding any weight. The X20 remains one of the lightest and most compact drive units on the market, weighing in at around 3.2 kg including the 236 Wh battery and motor controller.
Worth noting: for now, the update is only available for newly-produced X20 motors with the current hardware generation. If you’ve already got an X20 on your bike, you’ll need to wait a little longer for the digital boost. MAHLE say the update will be available for existing X20 systems from the end of 2025.
More than just software? The hardware updates in the latest X20 generation
Alongside the digital performance boost, the new generation of the X20 also gets a few tangible hardware upgrades. The motor now comes with a redesigned end cap and a new freehub, making it fully UDH-compatible. That opens the door to pairing it with SRAM’s latest Transmission drivetrains, which are gaining traction fast.
This is particularly exciting for the gravel segment. Manufacturers can now build e-gravel bikes that meet high-tech standards, with sleek integration, extra torque and the advantages of electronic 13-speed drivetrains like SRAM Rival XPLR, Force XPLR or RED XPLR. Combined with the performance upgrade, the X20 should now be more than capable of handling steep, loose climbs with ease. But does it really live up to the promise? Time to hit the test track.
Putting the latest MAHLE X20 to the test
A 10% increase in power sounds great on paper – but can you actually feel it on the road? In short: yes.
Since the firmware update, the X20 accelerates with noticeably more intent, especially in the higher support modes. This isn’t a 1,000-watt monster flinging you up hills at 25 km/h without a drop of sweat. It’s a precise and responsive push that enhances the bike’s vitality without changing what it is.
And that’s exactly what you want from an e-road or e-gravel bike: a light, agile setup that fades into the background above the 25 km/h threshold, but still takes the sting out of long climbs. The X20 remains a motor for riders who want to stay in control. The update simply gives it a bit more punch right where it’s needed most.
By design, hub motors have a disadvantage when starting uphill. Low speed and high resistance mean that the direct drive to the rear wheel requires a pedalling cadence that’s not always there. This is exactly where the new software tuning comes into play. When pulling away from a tight switchback or tackling a steep gravel ramp, the motor now delivers noticeably more oomph. It’s not a night-and-day transformation, but it is that subtle yet crucial difference that helps you find your rhythm quicker.
Once you’re in the flow, the assistance blends in seamlessly with your own power, ensuring a completely natural ride feel – so natural that you might even forget you’re even on an e-bike after a few kilometres. The only reminders are the motor’s soft hum at full tilt and your surprisingly low heart rate after reaching the top of a climb.
And what about range? In theory, it drops slightly due to the higher power output. But in practice, it never became an issue during our test rides. Above 25 km/h, our Ridley E-Grifn test bike just kept rolling smoothly under muscle power alone. That’s exactly the appeal: more support when you want it, and easy pedalling when you don’t.
MAHLE have managed to make their smallest, lightest and now most powerful hub motor even better. More power, more torque and the addition of UDH compatibility take the X20 to a new level – without compromising on weight or integration.
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Words: Jan Richter Photos: various
