Bosch's 5th generation CX motor could be seen fitted to dozens of bikes at the bike industry's biggest trade show, suggesting an imminent release.


You didn’t need to be Sherlock Holmes to spot Bosch’s next generation motor among the e-bikes on display at Eurobike. Some brands had made a half-baked attempt to cover-up the unreleased motor with black gaffer tape – which only really served to draw more attention to it – while others had completely undisguised motors bolted to their bikes. But while you could look at and touch the new motor, details about what’s new were much harder to come by. In fact everyone we spoke to remained extremely tight-lipped, and we got asked not to photograph the undisguised motors on one stand.

New Bosch CX motor spotted at Eurobike

The new Bosch CX motor spotted at Eurobike is clearly smaller than the Gen 4, and uses a two-bolt frame mount.

What we can surmise from examining the new motor is that it’s obviously more compact than the current CX unit – currently one of the best e-bike motors on the market. To put it into context, it’s somewhere between the dimensions of the current CX unit and the SX mid power option. It also appears to use twin fixing points, like the SX, instead of the triple fixings found on the current CX unit. Making the motor more compact, and reducing the number of mounting points, makes it easier for manufacturers to package their full-suspension frames, and gives more freedom to run shorter chainstays, optimise pivot points, and even create more space in the front triangle for water bottles and range extenders. It’s also conceivable that the smaller motor might come with a weight saving over the fourth generation CX motor.

The current Gen 4 unit uses a three-point mounting system, and looks bulkier.

There’s no way of telling whether the new motor gets a power and/or torque boost. The CX unit currently pushes out 85Nm and up to 600W of peak power, but with competitors such as SRAM’s Powertrain, Brose, DJI, and ZF pumping out 90Nm and well over 600W, maybe Bosch will turn up the wick to keep its most-popular motor at the sharp end.

Whyte E-Lyte 150 Works

Room for a top-tube mounted Kiox display? We think so.

Also interesting, and something first spotted on the Whyte E-Lyte launched last year, is a bigger cut-out on the top tube of many of these Bosch equipped e-bikes. Plainly there is some kind of larger and more sophisticated display coming that can be integrated into the frame. We imagine this will be along the lines of a Kiox unit, but mounted inside the top tube, giving advanced data, tuning, and navigation.

Assuming this new Bosch CX motor is coming down the line shortly, it’s our hunch that there will be some kind of battery update to complete the package. But for an idea of what form that might take, we have to look at the latest system launched by Bosch: Performance SX. If we look at the energy density of the SX’s 400Wh internal battery, it’s 200Wh/kg. That’s among the highest on the market, and shows that it uses the latest cell technology. Compare that with the larger batteries used with the CX motor, and the energy density is significantly lower; 170Wh/kg for the 750Wh unit. Plainly there’s an opportunity there for Bosch to upgrade its bigger batteries to the latest cells and either save weight, or increase range without adding weight. So you could end up with an 800Wh battery that’s 400g lighter than the current 750Wh unit, or a 750Wh battery that’s 750g lighter.

All this is speculation though, as we haven’t had any official communication from Bosch about a new motor, battery, or display.