There is hardly any other motor for which Bosch is as well known as for its top model, the Performace Line CX. Thanks to its high performance and strong torque, the drive was originally designed for use in e-mountainbikes. However, a look at the overall e-bike market shows that these characteristics are also useful in other bike categories: the CX motor can be found in numerous SUV, trekking and touring bikes as well as in various urban bikes. So it’s no wonder that we are also eagerly awaiting the new edition of this top seller and have even been able to test it!

And to say it straight away: anyone speculating on a major revolution will have to lower their expectations somewhat. The new and 5th generation of the full-power motor does not necessarily shine with new superlatives in terms of performance, size or weight. Nevertheless, Bosch has addressed all the criticisms of its predecessor and has improved the already very good basis of its predecessor with this evolution.

Bosch Performance Line CX (Gen 5): these are the new features:

• Lower weight: The motor with magnesium housing is now slightly more compact and narrower, but it weighs with its 2.8 kg around 100 g less than the 4th generation CX motor. The motor’s mounting points are compatible with those of the recently introduced Performance Line SX.
• Sensitive sensor technology: The motor’s sensor technology has been improved and now measures the pedal input more than 1,000 times per second — for dynamic and precisely tuned deployment to the respective driving manoeuvre and following the pedal input exactly. New inertial sensors (IMU) also measure acceleration and rotation rates in six dimensions and recognise incline and tilt angles as well as vibrations. This is how the e-bike ‘knows’ how steep the incline is. This IMU sensor also had its first test in the SX drive.
• Quieter noise: Some adjustments have been made to the gearbox to reduce the working noise of the motor and also to prevent the freewheel from clattering. The latter is certainly a clearly perceptible advantage when using the E-MTB, but the problem was less present in urban use anyway — at most you could hear this clacking on rough cobblestones.
• Reliable performance: With 85 Newton metres of torque, 600 watts of maximum power and up to 340 percent support, the motor offers the same performance data on paper as its predecessor, which Bosch describes as the ‘ideal ratio of power, dynamics, efficiency and range’. However, the drive has been optimised in terms of the continuous power with which the motor can assist at full power. With a new ‘hill start assist’, you can start uphill in a relaxed manner, which is comparable to a boost function on other bikes. The pushing aid has also been improved, with the drive unit adapting the pushing speed to the walking speed.

As the motor itself is only one component in the overall drive system, Bosch is also placing a lot of emphasis on the entire ecosystem with controls, displays, batteries, the ABS system and support for electronic shifting in its new products for the 2025 model year.

PowerTube 600 and 800: New batteries with high energy density

With its PowerTube 600 (with 600 Wh capacity) and PowerTube 800 (with 800 Wh capacity), Bosch is launching two new batteries that offer the highest energy density in the manufacturer’s portfolio with up to 205 Wh/kg. In concrete terms, this means that the PowerTube 800 battery weighs 3.9 kg, while the more compact PowerTube 600 weighs just 3.0 kg.

The form factor of the two batteries is also interesting: they are identical in length but differ in thickness. E-bike manufacturers can therefore design a standardised frame for the 800 battery, which can then also be fitted with the 600 battery. Alternatively, a slimmer frame can also be built, which can then only accommodate the thin 600 battery.

Both batteries can be removed — if the bike manufacturer supports this — according to the usual simple principle of the previous PowerTube batteries. In addition to the DualBattery function for the simultaneous use of two batteries, the new models are of course also compatible with the 250 Wh PowerMore additional battery.

Purion 400, the compact display

Bosch’s new Purion 400 display is a compact colour display that we already know from the Purion 200 — but without its operating laser. In contrast to the displays already available in the Kiox or Intuvia series, the Purion 400 is not positioned in the centre of the front of the handlebar, but can be mounted inconspicuously in the triangle between the stem and the inside of the handlebar — where it is also well protected in the event of a crash.

ABS Pro, eShift and Charge2Bike

Another new feature is the eBike ABS Pro, a particularly sporty tuning of the already familiar Bosch anti-lock braking system — which, however, is actually designed specifically for particularly sporty use. Much more interesting for everyday use is the eShift support, which enables automatic control of compatible e-chain gears. The test section below provides impressions of this promising system.

What Bosch’s collaboration in the Charge2Bike consortium promises, however, is still a vision of the future: here, all those involved are working on a standardised infrastructure for charging batteries. The concrete goal would ultimately be a standardised charging plug for all e-bike batteries. However, until this is achieved, an adapter will ensure compatibility between existing batteries and the new charging standard. Bosch is already showing an initial prototype, which will also be compatible with the older generation of batteries (even before the Smart System)!

On test: the new Perfomance Line CX (5th generation) with electronic TRP shifting

At the launch event, Bosch gave us the opportunity to test the new 5th generation Perfomance Line CX motor. The bikes were equipped with the electronic TRP E.A.S.I derailleur system with 12 gears and the eShift system as well as an ABS brake system and also had the new Purion 400 display fitted.

Of course, we took a closer look at the motor, especially with regard to its use in urban areas, and gained the following impressions on the test ride: Right from the start, the new motor impresses with its fine response behaviour and precise support — whether you’re just setting off on asphalt or climbing uphill on unpaved surfaces. The strength of the motor power always feels ‘right’, which means that the bike always remains easy and safe to control. The additional sensors therefore seem to have a positive effect here.

The clattering of the freewheel is actually no longer an issue, but the working noise of the motor is still audible — depending on the power required, of course. Certainly a little quieter than its predecessor, but thanks to the sonorous and rather deep sound, it is still hardly annoying.

In terms of the motor’s power and torque, the drive system has already been convincing in urban use — which also applies to the new model. It is the new software functions, such as the new hill start assist, that offer real added value in everyday use. Anyone who wants to set off on an incline with a fully loaded bike, for example, will love this function! The same applies to a function that prevents the bike from rolling backwards on a hill. The motor then uses its power in such a way that the bike stops on the spot.

The combination of TRP’s E.A.S.I A12 drivetrain and the Bosch eShift system also showed great potential, which was very convincing on tarmac and moderate terrain. You do have to get used to the fact that the electronics take over the shifting processes fully automatically. However, you soon realise that this works quite well and learn to appreciate the convenience of no longer having to worry about shifting gears. The system is already impressive for standard urban rides or touring. Only those who are very sporty on the road will probably still prefer to reach for the gear lever themselves — which is not a problem, as the trigger can also be operated completely manually and also offers the advantage of lightning-fast gear changes. We can only hope that this gear shifting system will soon find its way into as many bikes as possible — including many non-mountain bikes!

Getting used to it and familiarising yourself with it also applies to the ABS system, which prevents the front wheel from locking — no matter how hard you pull the brake lever. And here too, once you internalise the process and trust the technology, the ABS proves to be an easy-to-use system that can significantly shorten the braking distance thanks to the maximum braking force. To illustrate this better, a separate screen on the display shows the number of braking operations with ABS.

Conclusion

Bosch has made many adjustments to make the Performance Line CX motor even better. An evolution in the best sense of the word, which further refines the already proven and extremely popular drive system. All previous points of criticism have been addressed and the ecosystem around the motor has been expanded even more. The start for the new and 5th generation of the Performance Line CX has thus been made and numerous bikes with this drive are likely to be announced in the next few days.

What the future might bring, however, remains a matter of speculation: For example, Bosch surprised us with a subsequent software update for more torque in the previous generation of the CX motor; and then there are the speed and cargo variants of the CX motor for S-Dedelecs and Cargo Bikes, about which there is also no information as yet.