
Bosch Performance Line CX review: 120 Nm of torque over the Uetliberg
Bosch eBike Systems’ upgrade for the Performance Line CX and CX-R drive units in early May brought more support and torque for trails. I tested the new features at this year’s Cycle Week. My verdict? YES.
A year ago, my verdict on the Bosch eBike Systems Performance Line CX upgrade was: «Pure MTB riding fun». After trying the beta version of the drive unit for e-mountain bikes, I couldn’t wipe the smile off my face. Find out why here:
That was almost twelve months ago, and I’ve explored a lot of trails in the meantime. Now Bosch is upping the ante. Since 4 May, Performance Line CX and CX-R drive unit users have been enjoying increased power and intelligent power delivery. I’ve reported on this before:
Intelligent power delivery?
Before you rush off to angrily type in the comments, «Intelligent power delivery? That’s just marketing waffle,» wait a second.
What does Bosch eBike Systems mean by this? Besides increased maximum support (600% instead of the previous 400%) and more torque (120 instead of the previous 100 Nm), the company’s also introducing a drivetrain tensioner for improved control. Bosch says: «A software optimization closes the freewheel between the motor and rear wheel. This reduces the free travel on the pedal to a minimum and eliminates the usual delay when pedaling.» The result is improved power transmission.

Source: Bosch eBike Systems/Ilona Jeckelmann
One Uetliberg ride, please
As part of Cycle Week, I cycled up Zurich’s local mountain, the Uetliberg. I covered approximately 16 kilometres with a total elevation gain of almost 600 metres in about an hour and a half. This is what it looks like on Strava:

Source: Strava
What’s the upgrade for?
A special feature of the Bosch drive unit is the eMTB and eMTB+ modes, where the motor uses sensors to dynamically adjust support to your riding style and the terrain. Plus, Extended Boost in these modes allows you to roll over obstacles such as roots by applying targeted pressure to the pedal.
The Bosch eBike Flow app allows you to manually manage the performance improvements unlocked with the May upgrade. Especially on rocky, root-covered uphill sections, the extra Newton metres of torque and the additional boost are more than welcome. They allow you to tackle technical sections where you’d otherwise have to walk, following the motto «If you love your bike, you push it». This delivers more of a sense of achievement – and satisfaction.
Before longer downhill sections, I’d recommend dialling down the power a bit in the app. You don’t need that much power going downhill, and 120 Newton metres of torque isn’t always easy to control.

Source: Bosch eBike Systems/Ilona Jeckelmann
Who’s the upgrade for?
Bosch is specifically targeting a niche market with this upgrade. It’s aimed at cyclists who want extra – and intelligent – support on technically demanding uphill trails with lots of roots. The upgrade also emphasises personal responsibility, encouraging riders to decide for themselves whether and where the drive unit’s maximum settings make sense – and where they don’t. Beyond safety, wear and tear also comes into play: more power inevitably results in more wear on the components.
After the ride over the Uetliberg, I found myself back at Cycle Week in Brunau with a grin on my face and a cool iced tea in my hand.

Source: Bosch eBike Systems/Ilona Jeckelmann
From radio journalist to product tester and storyteller, jogger to gravel bike novice and fitness enthusiast with barbells and dumbbells. I'm excited to see where the journey'll take me next.
This is a subjective opinion of the editorial team. It doesn't necessarily reflect the position of the company.
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