E-bike motor ZF Centrix in a short test: New super motor for E-MTBs?
This article was first published on 26.6.24. In the meantime, we have been able to test the ZF CentriX extensively in the field and in the laboratory. You can read the current status of the ZF engine here:
The circular ZF Centrix e-bike motor impresses on paper with promising values. The drive is said to deliver 90 Newton metres and weigh just 2.5 kilos. That would be an unprecedented ratio of weight to torque. In addition, the round unit is really small with a diameter of 88 millimetres. "Barely bigger than a 0.33 litre drinks can," the manufacturer advertises.
Peak power is said to be 600 watts, which is on a par with Bosch's Performance Line CX (85 Nm, 2.9 kg) and Shimano's EP801 (85 Nm, 2.65 kg). Shortly before the start of the Eurobike 2024 the technology company from Friedrichshafen unveiled its big new product. We were able to use the opportunity at the trade fair for a first driving check.
ZF and e-bikes - wasn't there something before? That's right, ZF was part of the newly founded Sachs Micro Mobility joint venture in 2018. The brand entered the e-bike motor market in 2019 with the RS motor. (Click here for the first test of the 2019 Sachs RS powerhouse and all the technical details) ZF later bought all the shares in Sachs Micro Mobility. So ZF is not getting into the e-bike business out of the blue. Incidentally, the RS motor will continue to exist under the Sachs label.
The technology behind the ZF Centrix drive
The ZF Bike Eco System uses 48 volts, whereas most classic e-bike motors run on 36 volts. The circular shape, which is inevitably reminiscent of the motors from TQ, is particularly striking, like the lightweight HPR50 or the super powerful TQ HPR120. In fact, there are also certain similarities between the ZF and TQ engines on the inside.
Namely the round gearbox, which is significantly more space-saving and requires fewer components than the solutions from the classic Bosch and Shimano brands. This gives us hope that the ZF Centrix motor will do away with the annoying rattling from the gearbox and freewheel. More on this in the ride test below. Even if the shaft gear in the Centrix is not identical to the harmonic pin ring in the TQ drives, the design and functionality are similar.
ZF Bike Eco System: Batteries & controls
The Centrix comes with two battery variants of 504 and 756 watt hours respectively, which are mounted in the down tube using a special rail system. The Core Controller sits in the top tube as the control unit. This is where the system can be operated and the rider can see the most important information, such as the battery charge status, on a circular LED display. Optionally, a remote or a high-resolution colour display with touch function can be connected to the handlebars.
When it comes to mounting the batteries in the down tube, ZF refers to an "innovative rail system" that allows the batteries to be removed from the bike for charging or changing. Another special feature: the central control unit in the top tube, called the Core Controller, offers an interface via magnetic spring contacts that can be used to charge third-party devices such as smartphones.
With its own Eco System, ZF offers a complete package for bike manufacturers. However, the system is also open to products from third-party manufacturers. This applies to both control elements and batteries. This gives bike brands maximum freedom to realise individual concepts. This should be a major argument for many manufacturers, as the in-house batteries with 504 or 756 watt hours are rather heavy and also quite bulky.
The facts about the ZF Centrix
- Mid-motor with max. 90 Newton metres and 600 watts peak power
- Weight: 2.5 kilos according to the manufacturer
- Installation dimensions: 88 mm diameter, 118 mm width
- 48 Volt technology
- Two battery options from ZF: 504 or 756 watt hours
- Open for third-party batteries and controllers
Bikes with the CF Centrix e-bike motor
The ZF drive is brand new and there are no production-ready bikes yet. However, one model has already been announced: Raymon is launching a completely new platform with the ZF Centrix, the Tarok Ultra, for the 2025 model year. The full carbon frame provides 160 millimetres of suspension travel and is designed for a mullet setup with a 29er front wheel and 27.5-inch rear wheel. The battery with 756 watt hours can be folded forwards out of the down tube. The Tarok Ultra will be available in three equipment variants at the start of 2025. We are looking forward to the first test rides with the supposed super motor and will keep you up to date on our channels!
UPDATE: How the ZF Centrix rides - fact check at Eurobike 2024
The compact shape of the ZF Centrix immediately catches the eye. Unfortunately, the first bikes with the drive unit cannot quite maintain the slim line. This is because the down tubes are rather bulky compared to the compact motor. This is due to the rather angular and not exactly lightweight ZF batteries. However, bike companies can also use batteries from third-party manufacturers, which gives us hope.
Our first driving impression is ambivalent. The noise development is particularly noticeable: the motor hums like a turbine. In our perception, it tends to be somewhat louder than Bosch and Shimano, but with a pleasant frequency. Rattling noises from the freewheel, on the other hand, cannot be elicited from the Centrix. The unit also makes a very powerful impression - despite its compact size. Nevertheless, the Centrix is not impetuous or rough. On the contrary: when starting off, the ZF motor still pushes moderately and only accelerates to full thrust with one or two turns of the pedal.
This makes the power delivery feel smooth, but somewhat sluggish. With the significant overtravel ex works, the motor seems somewhat decoupled from the pedalling. The power of the Centrix also decreases noticeably at high pedalling frequencies from around 110 rpm. This could be a hindrance when accelerating before short counter-climbs or obstacles on an uphill section. We know a similar phenomenon from Shimano. Despite all the criticism, it has to be said that the ZF Centrix software does not yet correspond to the series status. It is quite possible that the developers will be able to make improvements here, especially with the currently still somewhat indirect use.
Conclusion on the ZF Centrix
Compact, light and powerful at the same time: never before has such a small motor been so powerful! In practice, however, the ZF Centrix still looks a little rough around the edges. And it's a shame that the angular and heavy batteries stand in the way of a sleek complete bike look and low overall weight. Nevertheless, the project is exciting - especially as ZF is a powerful company behind it. We are curious to see how the motor rides in series production. - Florentin Vesenbeckh, Head of Test and Technology at EMTB Magazine
Who is ZF?
ZF stands for Zahnradfabrik Friedrichshafen. ZF Friedrichshafen AG, also known as the ZF Group, has its headquarters in Friedrichshafen near Lake Constance. As a globally active technology group, it is mainly owned by the city of Friedrichshafen. It offers system solutions for the mobility of passenger cars, commercial vehicles and industrial technology. The ZF Group has 162 production sites in 31 countries.
In 2023, ZF generated sales of €46.6 billion with around 168,700 employees worldwide. The company invested 7.6 per cent of its turnover in research and development. The Zeppelin Foundation, administered by the city of Friedrichshafen, holds 93.8 per cent of the shares. The company was founded in 1915 as Zahnradfabrik GmbH.
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Florentin Vesenbeckh
Editor CvD
