Bosch eShift with TRP in the test: What can the new automatic shifting system for e-bikes do?
Adrian Kaether
· 17.01.2025
Shimano and Sram led the way, now Bosch is following suit. Since Eurobike 2024, Bosch's e-bike system has also been able to automatically change gears on sporty bikes with derailleur gears. According to the developers, the ideal gear is always preselected depending on the riding situation and a pre-set cadence.
A system that has clear potential. If you no longer have to concentrate on shifting, you have your head free for other things. This was our experience with Sram's Eagle Powertrain and Shimano's automatic transmission in the EMTB reader test.
Another promise: Suddenly finding yourself in too high a gear when stopping should also be a thing of the past with automatic gears. We test how well the Bosch system works and also give an outlook on the comparison with Sram and Shimano.
Teamwork: TRP circuit and Bosch algorithm
Like every automatic gearstick, the Bosch system works with two components. On the hardware side currently available is the new E.A.S.I. gearstick from TRP, which was introduced in conjunction with Bosch. It works on the principle of a conventional derailleur system and sorts twelve gears.
The range is - typically for mountain bikes - around 500 %. This means that both small mountain gears and large gears are available for fast descents. This sets the new eShift system apart from previous automatic gearsticks with Bosch. The Automatic gear hub from Enviolo from the trekking sector, for example, offers a much narrower range.
The second and perhaps even more important part of the system is the automatic algorithm. It is located in the Bosch control units and determines when which shifting process should be carried out. That sounds trivial at first. If you pedal too hard, you need a lighter gear. If you pedal too lightly, you need a heavier gear.
However, what is perceived as too light and too heavy can vary depending on the riding situation. If you tackle a steep ramp in Eco mode, you will generally pedal faster than with high support and a steady ride on the flat.
The system should also react quickly to changes in gradient and speed, but not constantly switch back and forth. Otherwise it will end up being more of a nuisance than a benefit. How exactly the algorithm works is a company secret at Bosch, as it is at all its competitors.
In principle, all bikes with Bosch's Smart System are compatible, but the gearstick itself is not currently sold as a retrofit part. Theoretically, the Bosch algorithm could also work with gears from other manufacturers, but nothing is currently known about this.
Bosch eShift in practice: how the automatic gearshift works
As part of our tests with the new Bosch Performance CX (test here) we were able to test Bosch's new automatic gearshift system on a prototype bike and also the new ABS Pro e-bike (tested here) to get a precise impression.
Setting up the automatic gearshift is very simple. Set the cadence, get on and ride off! The automatic system can be switched on and off and adjusted using the additional button on the shifter, the e-bike menu (Kiox, Purion 200, Purion 400) or via the Bosch eBike Flow app.
In practice, eShift usually works without complications and reliably sets sensible pedalling frequencies in smooth operation. For example, when commuting or on the way to the trail. However, even here it is noticeable that the TRP's gear changes are sometimes a little choppy under load. This is a particular problem with automatic gears, as the rider can no longer anticipate the shifting process and has to take some of the load off the pedals.
Unfortunately, the system is unable to cope even with moderate braking for stops such as at a red light. Shifting into a low gear to start off is then initiated but not completed. When you start off again, the gearstick often acknowledges this with a loud metallic clonk when the cassette is maltreated by several gear changes at once.
The fact that the TRP drivetrain currently still works with a classic Hyperglide cassette may also play a role here. Unlike Shimano's Linkglide or Sram's Transmission cassettes, this is not designed for shifting under load.
Bosch eShift on the trail: can the automatic transmission score here?
The less than smooth gear changes with high motor power are also the downfall of Bosch's eShift drivetrain in combination with TRP on the trail. The Bosch algorithm seems to work well here.
However, the metallic noise when the cassette is maltreated with a gear change in the middle of a steep climb can easily throw you off your stride. You can hardly speak of the additional comfort provided by the automatic shifting system. The Hyperglide is also likely to have a noticeable effect on material wear.
Like all automatic gearsticks, Bosch's eShift system also has the problem that it can only react, but not look ahead. For example, if you pick up speed on an uphill section of terrain, the system shifts far too quickly into a difficult gear that is unsuitable for the level.
If the gradient changes suddenly, the automatic mode often reacts too slowly. We would therefore always switch to manual mode for demanding uphills or steeply changing gradients. This is not an exclusive Bosch problem, as the Sram and Shimano systems also have clear weaknesses in this application scenario.
We have praise for the operation of the eShift system. Setting the cadence is simple and can be done in just a few seconds. The electronic shifter from TRP does not require any cables and impresses with defined feedback and little risk of confusion with the shift levers - this has been significantly worse with other electric shifters. Only the additional button for switching the automatic system on or off could provide clearer feedback.
Conclusion: Sram, Shimano and Co. - How Bosch compares
Bosch's automatic system scores highly in terms of ergonomics and interface, and the TRP shifter is also a success. However, the Hyperglide cassette currently used by Shimano does not cope well with shifting under load. Not only did we find this annoying on the trail, but the harsh gear changes were also annoying when commuting at every traffic light stop. TRP should definitely make improvements here before the system is widely available. - Adrian Kaether, Test & Technology Editorial Team
More about the automatic gearshift:
Adrian Kaether
Editor
