Testing the Bosch Performance CX: Bosch's e-bike motor in a long-term check
Adrian Kaether
· 09.01.2024
Relaunch for 2022: The Bosch Performance CX becomes "Smart"
At the end of 2021, Bosch announced the introduction of a completely new drive system with great fanfare. A surprise for many: the motor itself appears to have remained unchanged. The same appearance, the same performance data, even the name is the same as before: Bosch Performance CX. New on the so-called "Smart System" were the larger batteries with 750 watt hours and the control units. For the first time, the Smart System now also had its own app and a big promise: Lots of future features, made possible by the computing power of the "Smart System".
After more than two years of experience with over 50 different test bikes and around 10,000 test kilometres, we can show you how the Bosch really performs in tough everyday cycling conditions.
Bosch Performance CX: The facts
- Weight: 2.96 / 2.7* kilogrammes (EMTB measurement)
- Max. Torque: 85 Nm torque (manufacturer's specification)
- Max. Power: 600 watts (manufacturer's specification)
- Max. Support: 340 / 400* per cent
- Support levels: Eco, Tour+, E-MTB, Turbo, Race*
- Battery sizes: 500, 625, 750 Wh
- Range extender: 250 Wh
- Modes customisable via app
*Specifications refer to the CX Race
Power and torque: how the CX performs in the lab and in practice
With a torque of 85 Newton metres and a power output of 600 watts according to the manufacturer, the Bosch CX is the definition of an E-MTB motor. Not least thanks to the Performance CX, we also speak of an 85 Newton metre class when referring to classic units à la Bosch, Brose, Shimano and Yamaha. However, the manufacturer's performance specifications are only one side of the coin. We therefore always subject the motors to our own tests in an independent test laboratory in order to be able to objectively compare the performance data of different motors afterwards.
The Bosch Performance CX is able to shine time and time again and spits out a real 79 Newton metres and a whopping 566 watts of peak power on the test bench. The Swabian drive is therefore very close to the manufacturer's specifications and is also very stable at speed. Even at pedalling frequencies of well over 100, it never runs out of breath. Practical, for example, to get a little momentum before difficult key passages.
Lively and sporty: the riding feel of the Performance CX
However, whether the full power of the Bosch CX can be utilised in practice is another question. With a maximum of 340 per cent support, the Bosch releases its peak power somewhat later than other drives, some of which offer over 400 per cent support. In concrete terms, this means that if you pedal 100 watts yourself, the Bosch provides a maximum of 340 watts on top. Only those who pedal 180 watts or more under their own power can call up the full power of the motor. If you pedal at a more leisurely pace, you may be faster with other motors - regardless of the maximum power.
In terms of riding feel, the Bosch Performance CX is right at the forefront. The motor pedals smoothly, can be metered excellently and yet never feels overly sensitive or nervous on the pedals. The relatively low idle travel helps when starting off, while the sporty design and high speed stability help when accelerating before key sections. A particular strength of the Bosch CX is the deliberate coasting in E-MTB mode. If the rider stops pedalling abruptly, the drive deliberately pushes a little further. This makes it easier to conquer steps and obstacles uphill. All in all, the Performance CX does not try to hide the e-bike feeling. It pushes in a sporty and lively manner, the phrase "natural riding experience" is less likely to come to mind.
>> Read more about castering in our original presentation of the feature in the previous Performance CX and in the test of the Bosch Performance CX Race <<
If you do get stuck on a climb, the push assist comes into play. The Bosch system is particularly well thought-out and effective. It can be activated simply by holding the down button for a long time and moving the wheel slightly. If you slip off the button or have to change your grip, the motor holds the position for a few seconds without the bike rolling back. Hill-Hold is what Bosch calls this feature, which is particularly useful on steep terrain.
Even if the background noise always depends somewhat on the frame and bike: The Bosch CX is not the quietest drive on the market. The riding noise is rather high-pitched and can be clearly heard even at low support levels. The drive rattles audibly downhill.
The range of the Performance CX: heavy batteries but high endurance
One of the most obvious innovations that came with the switch to the Smart System was the large batteries. Instead of 625, there were initially only large batteries with 750 watt hours, which are still the standard for the Bosch Performance CX today. The disadvantage of the large batteries: On the one hand, the high weight of almost 4.3 kilograms, and on the other, the enormous length. This made it difficult for bike manufacturers to build compact and lightweight bikes for the Smart System and also limited compatibility with small frames.
But we were quite astonished when the first test bikes reached the 2000 metres of altitude in our Standard test procedure climbed. For comparison: Very good bikes, such as those with the 726 battery from Darfon, were at around 1700 metres in altitude at the end of 2021, bikes with Shimano's 630 battery only at 1200 to 1300 metres in altitude. In countless standardised test rides, around 2000 vertical metres with the 750 battery is not uncommon. A value that can only be achieved by real range specialists with a 900 battery, for example Canyons Spectral:On CFis regularly topped.
From LED remote to system controller: Bosch CX control units and displays
The current generation of the Bosch Performance CX in the Smart System was presented with the all-in-one LED remote control unit. It is both a minimalist display and control unit and shows the battery status in 10 per cent increments as well as the selected support level. The LED remote is also Bluetooth-compatible and thus forms the interface between the app (see below) and the drive system. A similar all-in-one solution is the Purion-200 display, which was launched in 2023which is also mounted on the outside of the handlebars. The advantage: The Purion has a real small display. Here you can view the battery status in per cent and the most important riding data.
Instead of the LED remote, there is now also the System Controller top tube display, which offers the same functions and is controlled via the wireless mini-remote. This ensures a clean and sporty look without cables, especially on the handlebars. Optionally, each of the basic solutions - LED remote, system controller and Purion display - can be upgraded with one of the two larger Kiox displays or the smartphone grip. This allows even more data on the current journey to be displayed, and navigation is also possible in some cases.
The E-Bike Flow app - navigation, customisation, theft protection
With the introduction of the current Bosch system, the Swabian manufacturer is also using its own app for the first time. It can be used to fine-tune the level of assistance, for example. You can update the entire drive system wirelessly, view records of the tours you have completed and view lots of exciting information about the use of the bike. Which U-level was used and how much, calorie consumption and the rider's own performance and much more.
The app also has navigation functions, which are particularly useful in combination with the smartphone grip or a Kiox display. The app can now also be linked to Komoot or Strava. This makes it much more attractive for mountain bikers. If you want, you can also use the app as a key. This means that support is only enabled when the app is connected. Even more theft protection, including real-time tracking, is available with the optional Connect module. Additional features such as the e-bike ABS are also operated via the app.
The Bosch app has thus become one of the best digital solutions on the market. However, there are still some issues. The fact that only one bike at a time can be registered in the app and connected to it is likely to annoy anyone who wants to configure and manage several bikes with one smartphone. For security reasons, Bosch also continues to rely on the closed system strategy. This means that, with the exception of the Apple Watch and a few heart rate monitors, third-party devices cannot be connected to the app and thus to the drive system. This also applies, for example, to the bike computers from Garmin, Wahoo, Sigma and Co.
Bosch CX or CX Race: these are the differences
In addition to the well-known Bosch Performance CX, there are now also the special edition Performance CX Race, which has been specially optimised for e-bike racing. It differs from the standard CX primarily in that it weighs 150 grams less and also has the special "Race" drive mode. This provides up to 400 per cent support, which means that the motor's peak power is already available at 150 watts instead of 180 watts. And speaking of peak power: the 85 Newton metres and 600 watts of the normal CX remain the same.
On the other hand, Race mode offers a greatly extended trail, which pushes the bike almost two metres forwards when the rider has already stopped pedalling. This is particularly helpful over rough terrain and off-camber sections. If you master the feature properly, you can tackle challenging sections with unavoidable pedalling pauses without the support ever cutting out. For uphill tricksters and all those who like to play with difficult uphill passages, this brings a whole new riding experience and new possibilities. The disadvantage of the race motor is that it is limited to the top models by most manufacturers and costs between 500 and 1000 euros extra, depending on the manufacturer.
CX, Shimano, Brose? The Bosch in comparison with the competition
But a Bosch or another drive? Almost everyone is likely to be faced with this question when buying a new e-bike. However, you should never decide in favour of one motor alone, but always consider the entire bike. Of course, the question of the right drive is still relevant. We have already been able to test almost all common e-bike drives extensively in practice and in the laboratory and provide a brief overview of the differences in measured values and riding experience.
In the lab: Bosch powerful and speed-resistant
In the laboratory, the Bosch Performance CX is definitely one of the more powerful e-bike drives. It offers excellent torque in the lower range and tops almost all conventional drives with its peak power, with the exception of real powerhouses such as Rocky Mountains Dyname 4.0, the Sachs and the old TQ HPR 120. However, the Drive S Mag from Brose offers almost the same top performance as the Bosch and even a little more torque, including Shimano's new EP801 has almost caught up with the Performance CX in terms of performance. Only the PW-X3 from Yamaha, which is also the basis of Giant's Syncdrive Pro II drives, still lags noticeably behind.
>> You can read more about peak performance in comparison in our Uphill race field trial with the eight most important e-bike motors on the market <<
In practice: Bosch sporty and sensitive, Brose shines with sound and torque
In terms of riding feel, the Bosch is sporty and dynamic and only releases its high performance when pedalling hard. Conversely, this means that if you don't pedal quite as hard, Brose and Shimano in particular can deliver a little more power. This is due to the fact that the Shimano, for example, already gives full throttle at 100 watts of rider input, while the Bosch only releases its full power at 180 watts. In practice, this is noticeable on relaxed tours, for example, where you are often faster with Shimano and Brose than with the Bosch when pedalling lightly.
On the other hand, the power modulation with the Bosch is excellent and, in our experience, slightly better than with Yamaha and Shimano. The Brose is closest to the sensitivity of the Bosch drive, often impresses with its low noise level and does not rattle downhill. However, the well thought-out pedalling assistance, the long system range and the extended overtravel in E-MTB mode are all in the Bosch drive's favour.
>> Which engine best suits which rider is still partly a matter of personal preference. We therefore strongly recommend a test drive when making concrete decisions. <<
Reliability in long-term operation: Does it run and run and run?
While other drives, such as the Drive S Mag from Brosehave been criticised for their lack of reliability, there has been little to report about the Bosch so far. Isolated failures in our tests were only ever due to trivialities such as defective speed sensor cables or loosened plug connections in the cabling. In comparison to the other motors, we would attest to the outstanding reliability of the Performance CX. We also hear the argument of reliability and service again and again from the manufacturer when it comes to a new bike with a Bosch drive.
Bosch rightly the market leader? The EMTB conclusion
The new Bosch drive didn't have it easy at first. Heavy and bulky batteries, a lack of backwards compatibility and an app with few features initially led to criticism. Today, however, the Bosch is rightly one of the best-selling drives on the market. The ride feel, range and performance are particularly appealing to sporty riders, and Bosch has made significant improvements to the app. Nevertheless, there is still room for improvement for the next generation in terms of the soundscape and downhill rattling.
Strengths
- Always enough power
- Excellent dosing capability
- App, overrun, push assistance
- High range
Weaknesses
- Batteries are heavy and long
- Drive noise could be quieter
- rattles downhill
Adrian Kaether
Editor
