The Insider's Guide to MAHLE X20: Updates, How-Tos, and Our Favorite eBikes

We’ve had great success with the MAHLE X35 drive unit. Not only is it one of the most common electric bike systems in lightweight road and gravel electric bikes, but it was so low-profile in it's look that the only way one might realize an X35 bike was electric was by lifting it up. The new MAHLE X20 system - shown here on a BMC Roadmachine AMP TWO - offers up plenty of improvements that make the bike a noticeable step forward.

This latest MAHLE Smartbike system is lighter, smarter, and overall a much more user-friendly experience. The wildest part of it all? The system weighs in at just 7 pounds (3.2 kg), and that’s including the 250 W battery option in the downtube.

In this writeup - and video review - we’ll give an overview of the features, how it's changed over the MAHLE X35, and whether the changes amount to a better electric bike.

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MAHLE X20: What Is It?

MAHLE X20 is the latest drive unit system from manufacturing giant, MAHLE. Better known for making components for automobiles of all kinds, the German company in recent years branched out into ‘e-mobility.’ In late 2018, MAHLE purchased the Spanish company responsible for Ebikemotion and the Ebikemotion X35, a drive unit we have become quite familiar with. 

Expect to see the MAHLE X20 on the likes of bikes such as the BMC Roadmachine AMP, Orbea Gain, SCOTT Addict eRIDE, and more over the coming period. It's low weight and lower power numbers make it a popular choice for road bikes and gravel bikes, particularly for those who want the ride feel and handling of a standard bicycle, just with a little bit of extra help.

What’s New with MAHLE X20?

It is always a fight to make electric bikes feel natural when riding. Its even harder to do so when you’re trying to keep the system as lightweight as possible. But MAHLE really focused on improving ride feel, and they seemed to have pulled it off here. 

This is done through the inclusion of a torque sensor, a first for MAHLE. This sensor - effectively built into the bottom bracket of the bike - measures pedaling force exerted by the rider through the cranks to more precisely give out power as needed. While most mid-drive electric assist units have one built in, a torque sensor adds complication and weight, so the X35 calculates how much it offers assistance by comparing wheel speed to how fast the cassette is spinning. Adding a torque sensor takes some of the guesswork out. 

As far as ride feel is concerned, MAHLE claims the X20 offers even more torque than X35, with a claimed peak of 55 Nm compared to 40 Nm from the X35. While this is lower than the biggest assist units from Shimano and Bosch, it is comparable to units from Fazua and others while being lighter. 

MAHLE’s thinking is that a lower peak torque is necessary here, as these bikes often will have lower grip from narrower, road-oriented tires. The lower max assist also should be smoother, without the jerky feel of the most powerful systems.

Speaking of assist, MAHLE motors are spec’d on Class 1 e-bikes with a 20 mph max pedal assist. You’ll feel the motor start to taper off its assist as you approach 20 mph to make the transition smooth.

MAHLE Controller Updates

Another noteworthy change is the updated controller, now called the HMI head unit control. Its location will differ from bike to bike, but for the most part, will be found either on the stem or the top tube. The new controller aims to be simpler to understand, with a dynamic battery level line that shrinks as the battery gets used. This line still shows assist levels as they are chosen, but the separation of button and LED indicator - alongside the new haptic feedback - makes it easier to use. 

 

The previous iWoc ONE controller was often hard to understand, with LED colors indicating a combination of battery life, connectivity, light options, and assist levels. While the LED colors still require some homework to understand their meaning (which we’ll get into), the big difference is the LED bar that shows battery life. Is there more of a white light showing? Then there’s more battery. And if your battery is low, then the light bar will be dim.

The HMI controller shows four colors to indicate the assist level. White for no assist, green for low assist, orange for medium assist, and then red for the highest, most aggressive assist. A yellow light indicates the lights are on or off. A blue light indicates a Bluetooth connection is being connected or disconnected. See a flashing orange light? That is a warning that functionality is limited; you can continue riding, though keep an eye out for what might be wrong through the MySmartBike app.

Controlling assist doesn’t only need to happen through the HMI controller. MAHLE have also designed a set of optional e-shifters. These little shift buttons are wired, but can be placed almost anywhere. This allows riders to easily change assist levels from the handlebar. 

There are also now three battery options to power the MAHLE X20. The standard battery found on most bikes is 236Wh. Manufacturers will have the option of a larger capacity 350Wh internal battery for frames with more downtube space. All X20-equipped electric bikes can add a range extender battery that adds 172Wh. This extender adds up to 6000 ft of climbing ability, at least according to Orbea.

MAHLE X20 Makes It Easier to Remove the Rear Wheel

Arguably, one of the most important changes from the X35 to the X20 come in regard to usability. X35 rear wheel removal required separating a delicate-feeling plug from the rear wheel, unscrewing the screws on both sides, then negotiating the chain around the cassette in the way that can sometimes be difficult on the side of the road. The X20 now gets rid of the external power wiring of the X35 and adds a special keyed dropout insert connector. There’s only one way to put the wheel in, and once it is in place, the wheel and bike are connected.

 

The MAHLE X20 system now uses a standard 12mm thru-axle bolt to remove and install the rear wheel, the same as any normal disc brake bike.  If you can remove a rear wheel on a normal bike, you can do it on this one.

According to MAHLE, a battery charge should offer a quoted 100 km (60 miles) and 1750 meters (5740 feet) of climbing ability with the smaller internal battery, and up to 200 km (130 miles) with the bigger battery and range extender . These numbers are somewhat optimistic in our experience. We’ve seen riders get anything from 40 to 100 miles of range with the X35; we expect a similar number here too. 

Bikes with MAHLE X20

MAHLE intends for the X20 electric drive system to be used in lightweight, high-performance gravel, road, and cross-country bikes. All of these bikes are designed not for range or power, but to be fun to ride, and a pleasant way to get around. Bikes with the MAHLE X20 drive system include the BMC Roadmachine AMP TWO, Orbea Gain, and SCOTT Addict eRIDE.

BMC Roadmachine AMP

Put a BMC Roadmachine AMP next to a standard Roadmachine, and you’d be hard-pressed to tell the difference between the two bikes. Really, the downtube is slightly larger than the standard Roadmachine, and the rear end is slightly different. But what the Roadmachine AMP offers is a SRAM Rival eTap AXS drivetrain, a lightweight carbon frame, and the exact same geometry as the standard road bike. 

Currently, BMC offers the Roadmachine AMP ONE with a MAHLE X20 drive system. It features a 350 Wh battery with the option for a range extender.

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SCOTT Addict eRIDE

SCOTT says the new Addict eRIDE is a version of the Addict RC road bike, just electrified. We’d call it closer to the standard Addict, but that’s no bad thing. Geometry is decidedly endurance oriented, with an aim for a more comfortable rather than more aggressive rider position. The wheelbase is slightly longer in an effort to improve high-speed stability. But the classic tech is there: fully-integrated cable routing, a D-shape seatpost, and aero tube shaping. 

SCOTT currently offers the MAHLE X20 system in five models in the Addict eRIDE lineup. Four are standard Addict eRIDE bikes and one is the Contessa Addict eRIDE 15. All feature the smaller (and lighter) 250 Wh battery, though a range extender is bundled with the Addict eRIDE Ultimate.

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Orbea Gain

The Orbea Gain is consistently one of our most popular electric bikes in the shop, and for good reason: there are so many options! Gain is available in both alloy and carbon frames with several build kits each. Alloy Gain models stick with the MAHLE X35 system we've come to appreciate. Carbon Gain models receive the X20 system, the larger 350 Wh battery, and the handlebar-mounted e-Shifters as standard. Pair that to Gain's all-road design and geometry and we think Gain will continue to find many a happy home. 

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Conclusion

A good electric road bike or electric road bike isn’t just throwing a battery pack on a bike and calling it a day. Rather, it requires a whole lot of finesse, smart engineering, and precision to make a cohesive bike that happens to have electric assist. While the MAHLE X20 isn't just limited to one bike, our experience with the new MAHLE X20 on the BMC Roadmachine AMP indicates a balance and feel of sophistication that wasn’t there before. A worthwhile upgrade indeed.

Have any questions about electric road bikes or electric gravel bikes? Come talk to the experts at Contender Bicycles. With different companies using MAHLE, Bosch, Shimano, TQ, and more, we have everything you need to find your next dream bike.

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