Key Features at a Glance

The CX-R is currently one of the most powerful motors on the e-MTB market. Its specs are impressive. It delivers up to 100 Newton-meters of torque, provides a maximum power output of up to 750 watts, and offers up to 400 percent assistance. It is the only Bosch motor to feature the “Race” riding mode. With the launch of the current CX-R, the “eMTB+” mode was also introduced, which is now available in the 5th generation of the “Performance Line CX” as well.

The motor not only differs from the regular CX in terms of performance data; it is also partially constructed from different materials. Thanks to a titanium crankshaft and high-quality ceramic ball bearings, the drive weighs just 2.7 kilograms.

First Impressions

A “Moustache Game 160.9 Race” was available as a test bike. What makes this bike special is that the motor is not integrated into the frame but is mounted as a freestanding unit. It’s rare to get such a good look at a motor. You can see that one side of the CX-R has smooth surfaces, while the other has massive cooling fins.

As is customary with Bosch, all riding modes can be customized in the in-house Flow app. Since this is a race motor, all parameters were set to maximum power and fast response. If you usually ride your e-bike in Eco mode, you don’t need to read any further. This test was conducted under the motto “racing only”; other modes were not tested—it was “all in.”

In action

As soon as you sit on the bike and place a foot lightly on the pedals, the drive reacts immediately and starts to jerk. Aha, someone wants to step on the gas! Well, let’s get going. As soon as you start pedaling, you’re already at 25 km/h. When transitioning to 26 km/h, the motor becomes a bit sluggish, as the assistance stops here. The trick is to keep the speed at a maximum of 25.5 km/h on flat terrain and gentle inclines; then it moves along smoothly.

The Bosch motor likes a cadence of over 90 revolutions per minute; at that speed, you can zip up even very steep ramps at an unusually high pace. If you stand up out of the saddle on a gravel climb, the sensors react and reduce the assistance so the rear wheel doesn’t spin out. If the uphill section becomes technically challenging, it’s time to ease off the throttle. The CX-R has so much power that it’s difficult to maintain control of the bike and avoid charging into obstacles with too much speed and energy. Here, it’s advisable to either reduce the assistance level or shift into a lower gear; otherwise, the handling becomes too aggressive. It takes a few rides to get the hang of the “Extended Boost” and the follow-through. Once you’ve got the hang of it, you can tackle steps and obstacles that were previously unrideable.

When going downhill, motor assistance is rarely needed and usually only when accelerating out of hairpin turns. It takes some time to figure out which gear and how much pedal pressure to use when accelerating through turns without sending yourself flying. Especially in tight hairpin turns and when leaning heavily into a curve, overly aggressive assistance can cause the bike to understeer, catapulting you over the handlebars or throwing you sideways to the ground.

Conclusion

The “Bosch Performance Line CX” really gives you a kick in the pants. But you have to be able to control it. It’s certainly a good choice for use in e-MTB races. For recreational use, a certain level of riding skill is required. Otherwise, it’s like riding a Porsche Cayenne through downtown Zurich.

Recommendation

It makes sense not to set the assistance levels to maximum right from the start, but to warm up with the standard setting first. Gradually increasing the power helps you slowly work your way up to full race mode.

Manufacturer

www.bosch-ebike.com