A recent patent from Shimano, published to the USPTO database yesterday, reveals a new, more compact e-bike motor system. The drawings depict a motor that appears to have a smaller footprint than any of the EP8 and EP6 series motors that are currently powering a swathe of eMTBs, and perhaps even smaller than the STEPS E7000 motor that powers some gravel e-bikes.
The patent suggests the drive unit could be used on a mountain bike, road bike, city bike, cargo bike, or a recumbent bike.
However, Fig. 1 of the patent depicts a drop bar bike that happens to be home to a suspension fork (and, somewhat amusingly, rim brakes). That would suggest the system could be geared toward road or gravel e-bikes.
Shimano motors are powering some current road and gravel e-bikes, but they don’t have quite as big a piece of the pie as they do in the world of eMTBs. That could be because they simply can’t compete on weight (or looks).
The Giant Revolt E+ is a prime example of a Shimano EP8 powered gravel e-bike. It offers a whopping 85 Nm torque, and is paired with a 500 Wh battery. While it may offer an impressive range, it is no looker, and the motor alone contributes around 2.7 kg to the overall weight.
Shimano does offer a slightly more compact, mid-power motor in the STEPS E7000 drive unit. You’ll find it on a couple of gravel e-bikes, the Cairn BRAVe 1.0 being one such example. It is less powerful than the EP drive units with a maximum torque of 60 Nm. Despite that, it’s actually around 100 grams heavier than the latest, full-power EP801 model. For some reason, we don’t see the STEPS E7000 paired with a battery that is fully enclosed within the downtube, something that, again from an aesthetics point of view, is a bit of a must-have.
From where I’m standing, there is a big gap in Shimano’s offering; that’s a lightweight, mid-power, mid-drive motor that offers a neat, integrated solution for high-end road and gravel e-bikes. Something that could compete with the likes of the TQ-HPR50 rocked by the BMC Roadmachine 01 AMP X (and others), or the Fazua Ride 50 seen on the Vitus E-Substance Carbon (and others).
Both of the aforementioned drive units weigh less than 2 kg, and are svelte enough to fit into the bottom bracket area without making the bike look like it’s about to deliver its offspring.
Now, it seems, Shimano may have an answer to that. This latest patent reveals a new mid-drive motor and battery configuration that has a much lower profile than any of the current EP8, EP6 or E7000 offerings. It shows multiple ways in which the battery could be connected to the motor, the important bit being that the battery is able to slot down underneath the motor which appears to be tilted up the way.
Admittedly, we’re being highly speculative here. Though a torque sensor, one-way clutch and other motor hardware are mentioned, the patent doesn’t actually focus on the drive unit’s design. Rather, it pays a great deal of attention to the way in which the drive unit is connected to the battery. In fact, the two appear to be tied to one another by virtue of the motor accommodating the holder in which the battery is intended to be securely held.
Regardless, the images do indicate Shimano is looking at developing a lighter, more compact e-bike motor that could serve the eRoad and eGravel markets, if not the SL eMTB market, too. To be competitive, it would likely need to have around 40-50 Nm torque and weigh no more than 2 kg.
Those numbers would put it on par with the TQ-HPR50 (on the Scott Solace, for example) and the Fazua Ride 50 (on the Trek Domane+ LT, for example).
We have reached out to Shimano for comment.