Bosch has released version 1.38 of the eBike Flow app. After the update, your electric bike can gain four new features without changing a single part.
Two of them change how the motor pushes: traction control and the Drivetrain Tensioner. The other two change what you see on screen: Trick Check for jumps and tricks, and the remaining charging time. Here is what each one does, and on which bikes.
Source: official Bosch eBike page "Flow App version 1.38", consulted on 16 October 2026. Prices: the lowest in our online catalogue on that date, all model years combined. Applies only to bikes fitted with the Bosch smart system.
4
new features in the app
4
traction control levels
1.38
eBike Flow app version
Traction control: less wheel spin
On slippery ground, too much torque makes the rear wheel spin. Traction control meters the motor's torque so you keep grip.
You set it separately for each assistance mode. So you can switch it off in Eco and set it to the maximum in eMTB, or the other way round. Bosch gives a simple rule: in dry conditions, a low level favours performance; on loose, wet or technical ground, a high level improves control.
Four levels, per assistance mode
→ Off
→ Low — dry ground, chasing performance
→ Medium
→ High — mud, leaves, roots, rocks
Where to set it in the app
→ Individual riding modes › Advanced › Traction control
Compatible motors (traction control and Drivetrain Tensioner)
→ Performance Line CX-R (BDU386Y)
→ Performance Line CX (BDU384Y)
→ Cargo Line (BDU384Y)
Drivetrain Tensioner: a more direct pedal stroke
The motor puts the drivetrain under slight tension. The small dead spot at the first pedal stroke disappears.
You feel it mostly when accelerating: out of a corner, pulling away from traffic lights, or on a technical climb where every quarter turn counts. You switch it on or off in the eBike Flow app, one assistance mode at a time. It applies to the same three motors as traction control.
Good to know
→ The Drivetrain Tensioner is off by default in all modes.
→ After the update, nothing changes until you switch it on yourself.
Trick Check: your jumps stay on screen
Trick Check measures your tricks. With version 1.38, the values stay displayed until the next trick.
You add the "Trick Check" screen from the display configuration in the app. When you start an activity, it shows "Waiting for trick". During the jump the values update live; on landing, the maximums stay visible. No more glancing at the handlebar in mid-air.
MOTORS Performance Line CX-R (BDU386Y), CX (BDU384Y), CX Race (BDU374Y), CX (BDU374Y) and SX (BDU314Y)
DISPLAYS Kiox 300, Kiox 400C, Kiox 500, Purion 200 and Purion 400
NOTE display configuration is not available on the Purion 400
Charging time: you know when you can ride again
Plug in the charger: the bike's display shows how long until the battery is full.
It is shown in hours and minutes, up to 100%, for as long as the charger stays connected. This is the change that reaches the most riders: it works on every smart system display except the Intuvia 100.
With the eBike Flow+ subscription
→ If your bike has a ConnectModule and you subscribe to Flow+, the remaining charging time also appears live in the app on your phone.
→ Flow+ is a paid Bosch subscription, subject to its own terms of sale.
Which bikes get these features?
Two of the new features depend on the motor: traction control and the Drivetrain Tensioner need a latest-generation Performance Line CX, CX-R or Cargo Line. To make sense of the Bosch references, our complete guide to Bosch motors, batteries and displays explains them one by one. Three examples from the catalogue:
The versatile all-road bike: a hardtail with the Performance Line CX, at ease from the daily commute to forest tracks.
A full-suspension mountain bike for demanding rides. This is where traction control shows most, on wet roots.
A longtail for the kids and the shopping. On a loaded bike, a more direct pedal stroke makes every start easier.
The features depend on the exact motor fitted to the bike, not on the model name. If in doubt, ask us to check your motor reference.
How to install the update
The update happens in two steps: first the app, then the bike. Bosch notes that it can take several days to appear in the App Store or Google Play Store.
In practice
→ 1. Update the eBike Flow app on your phone (version 1.38).
→ 2. Check that all components are correctly fitted to the bike (battery, display, remote).
→ 3. Start the bike update from the eBike Flow app.
→ 4. Set up the new features in the individual riding modes.
Your questions
My bike doesn't have the smart system. Does this apply to me?
No. The eBike Flow app and these four features only apply to bikes fitted with the Bosch smart system. Older systems do not receive them.
Should I switch on traction control in town?
It isn't necessary. It is mainly useful on loose, wet or technical ground. On dry roads, a low level or off is enough. Since it is set per mode, you can keep it for the mode you use off-road.
I feel no difference after the update. Is that normal?
Yes, if you haven't switched anything on: the Drivetrain Tensioner is off by default in all modes. Also check that your motor is on the compatible list.
Do I need a subscription to see the charging time?
Not on the bike's display: it is free on every display except the Intuvia 100. The Flow+ subscription (with ConnectModule) is only needed to see it in the app as well.
Can the shop install the update for me?
Yes. Drop by our workshop in Liège or Brussels: we update the bike and show you the new settings.
Fancy a bike that gets the most from these new features?
Browse our Bosch bikes online, or come and try them in our Liège or Brussels shop.