Mahle e-bike drive systems just got substantially lighter thanks to the big weight savings in their new, more compact X20 hub motor. Already one of the most popular lightweight e-bike powertrains for road & gravel, the new X20 completely refines & modernizes Mahle (formerly eBikemotion) pedal-assist performance while becoming the “lightest e-bike drive system on the market” beyond its improved power:weight ratio.
It is even said to be more powerful now, with 37.5% more peak torque!
Mahle X20 lightweight e-bike drive system
The previous Mahle hub motor was probably already the most common drive system we’d find in lightweight road & gravel e-bikes. Combining a lightweight 250W motor in the hub of the rear wheel, balanced with a small 250W battery hidden inside the downtube of bikes from the likes of Cannondale, GT, Orbea, Rose, Scott, Simplon, 3T, Urwahn & Wilier (to name just a recent handful), it was a simple and unobtrusive solution that often didn’t even require major changes to those e-bikes’ analog analogues.
But now, the X20 hub is simply better all around.
It’s lighter, smoother, easier to get on & off the bike, better integrated, less obtrusive. Interestingly, it’s also a bit
less more powerful with the same rated 250W power but higher peak torque, at the same time getting an added benefit of longer ranges, too.
Tech details – What’s new?
The new complete Mahle X20 system now weighs just 3.2kg, down 300g from the X35. That’s why Mahle calls it the “lightest e-bike drive system on the market”. The smaller diameter hub itself drops even more weight than that, around half a kilo down to just 1399g, now that its weight also doesn’t need to include its axle or freehub.
Those are now both able to be pulled out as the X20 uses a more standard 12x142mm thru-axle interface, and now an interchangeable freehub body that brings compatibility with Shimano HG, SRAM XD-R & Campagnolo N3W cassettes.
Mahle has upgraded the natural ride feel with a pair of new sensors measuring applied torque & cadence at the bottom bracket, to more smoothly ramp up pedal-assist support to match rider input thanks to smart “Artificial Intelligence” programming.
The new X20 hub is still rated at 250W but its official toque output scales
down up to real 23Nm at the hub (from 40Nm for the X35), which Mahle says equates to a 55-60Nm (compared to 40Nm for the X35) torque output from a mid-drive motor due to drivetrain gearing AND power transfer losses. That’s still a good bit less than the 85Nm of a top-tier Shimano EP8 or Bosch Performance Line CX motor, but more comparable to their second-tier motors or the lightweight Fazua system.
Mahle’s thinking (and one we can agree with) is that this relatively-lower peak torque combined with narrower tires of road & gravel bikes and intelligent power management systems, actually delivers a much smoother pedal-assist without the jerky feel of more powerful systems.
The side benefit of lower peak torque output is that pedal-assist range with these smaller batteries increases as well, so you can ride your lighter e-bike farther.
The smaller X20 rear hub motor also gets rid of the external power wiring of the X35, instead adding a special dropout insert (black element between rotor & frame, above) with a keyed interface that automatically aligns a waterproof plug connector (with red seal, below left) when you insert the rear wheel.
Compared to the separate wires and bolt-on axles of the X35 hub, this will make roadside flat repairs a much more manageable affair for anyone who can operate a regular QR thru-axle. A huge upgrade in user-friendliness!
With wired connections more hidden inside, a smaller diameter hubshell, and a conventional-looking thru-axle, the new X20 system simply disappears into stealthy e-bikes more than ever. Even when you know you are looking at an e-bike, it’s still hard to tell.
Mahle has added their own new ANT+ wireless Pulsar One cycling computer head unit design to interface with the X20 e-bike powertrain, while also pulling in your own external data from a heartrate monitor and/or power meter for ride tracking. They also have new optional E-Shifters which would allow riders to switch modes from the drops, and slimmed down their iWoc mode controller which can be integrated into the top tube, stem, or one-piece bar like on the Wilier.
There are also now three battery options to power the X20. The standard, now 236Wh internal battery carries over and they’ve added a larger capacity 350Wh internal battery for frames with more space in the downtube, plus the external Range Extender water bottle battery appears to have been scaled back to 172Wh to better fit in more e-bikes.
Mahle X20 Availability
So far, we’ve already seen the new lightweight Mahle X20 e-bike drive system made available in Wilier’s endurance road Filante Hybrid & Scott’s latest Addict eRide e-bikes. We expect many more lightweight road and gravel e-bikes to join in with X20 soon.
Mahle.com & more now at: Mahle-smartbike.com
“23Nm at the hub (from 40Nm for the X35), which Mahle says equates to a 55-60Nm toque output from a mid-drive motor due to drivetrain losses”
This cannot be right. What Mahle may plausibly have claimed is that 23Nm at the rear hub equates to 55 Nm at the cranks due to drivetrain gear ratio.
Exaggerating for sure. Based on their numbers the normal drivetrain plus the extra reductions in the mid-drive are eating up 60% or more of the power. I’m thinking more like 15-30%, so their 23nm would be like 29-33nm.
Not that I care, I’m happy to have a fraction of the power for a lighter bike.
@Eddie & Frank, you are both correct. My wording was too vague. It is the combined reduction gearing AND drivetrain transmission losses that Mahle estimates to make this 23Nm hub motor equivalent to a mid-drive 55Nm motor.
It is still not meant to be the most powerful option, like Eddie says, prioritizing lighter weight and smoother pedal-assist.
Will it be possible to upgrade the x35 to the x20 on an older bike?
@Ed, that’s pretty unlikely. The new system requires at least a 12mm thru-axle (vs. the old 10mm bolt-on), a special dropout insert to manage connection to the battery. Plus, there’s a new BB with sensors and likely new electronic management. I doubt many existing e-bikes would be so adaptable, and since Mahle sell to OEMs only, I can’t imagine it would be cost-effective to retrofit them. With that said, brands like Scott have shown that they will quickly make the changes to transition existing e-bikes to the new system, just not retrofits.
Is there any way to find the data for the BLDC like pole count? Conductor sizes and combinations and turn count?
Now I want a 15×110 version.
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Murat, this is a product that is not available to the public alone – it comes already assembled on the bikes mentioned in the article.