The latest Bosch Flow app update, version 1.38, rolled out last month and it hands more Smart System riders some of the fine-tuning that used to live inside Bosch's sportiest riding modes. At Electric Bikes Brisbane, we've been selling and servicing electric bikes since 2013, and working on Bosch systems since 2014. Here's what this update changes, who it's for, and what to watch out for. Plus some good news for phone-on-the-bars navigators: the Bosch SmartphoneGrip Vertical has landed in Milton.
Missed our last Bosch round-up? Our Performance Update 2.0 article covers 120Nm, heart rate data, faster eBike Lock and saved navigation favourites.
1. Adjustable Traction Control
What it is: Traction control manages motor torque so the rear tyre keeps gripping instead of spinning out. Bosch first used this kind of control inside eMTB+ mode, where it worked automatically and couldn't be adjusted. With 1.38, you choose how much intervention you want.
How it works: In the eBike Flow app, tap the settings cog, go to Custom riding modes > Advanced, and set traction control for each mode: Off, Low, Medium or High. When the rear wheel starts to break traction, the motor eases off torque to help it hook up again.
Who it's for: Riders on the Bosch Performance Line CX, Performance Line CX-R or Cargo Line (current-generation BDU384Y drive units). It's most useful on loose, dry SE QLD trail surfaces, wet roots after a summer storm, gravel fire roads, and steep driveways on a loaded cargo bike.
Considerations: It isn't magic. On very loose or very steep ground, the rear wheel can still slip, even on High. More intervention also means the motor holds back some torque at the moment you might want it, so experienced riders on dry, grippy climbs may prefer Low or Off. Because it's set per riding mode, a good starting point is a higher setting in your trail mode and Off in your road or commute mode.
2. Drivetrain Tensioner — Now in Every Riding Mode
What it is: Drivetrain Tensioner arrived earlier this year as part of the eMTB+ and Race modes. Version 1.38 lets you switch it on or off in every custom riding mode.
How it works: The motor applies a tiny preload, just enough to take up slack in the chain without turning the wheel. That removes the small dead spot (and the familiar "clink") at the start of each pedal stroke, so power goes in the moment you push. You'll find the toggle in the same Advanced settings for each riding mode.
Who it's for: Bosch Performance Line CX, CX-R and Cargo Line riders who want sharper, more immediate response, whether that's restarting on a technical climb or setting off on a loaded cargo bike.
Considerations: It's now off by default, so you'll need to switch it on. On a dual-suspension eMTB the constant preload can take a little sensitivity out of the rear suspension, so some trail riders may prefer it off on rough descents. The pedal feel is also different and can take a ride or two to get used to.
3. Accurate Charging Times on Your Display
What it is: Your display shows exactly how long is left until the battery reaches 100%, in hours and minutes.
How it works: There's nothing to switch on. After you update your bike's software through the Flow app, plug the charger into the bike, and the remaining time appears on the display automatically.
Who it's for: Any Smart System rider who charges with the battery on the bike. Every Smart System display except the entry-level Intuvia 100 supports it.
Considerations: The countdown appears on the bike's display only, not in the app. To check charging remotely from your phone, you need the Bosch ConnectModule and a Flow+ subscription. It also only works when charging on the bike, not when the battery is out and on the bench.
4. Getting Ready for the Bosch 12A Fast Charger
What it is: Version 1.38 adds a new fast-charging on/off setting under Charging in the display settings. It's groundwork for the Bosch 12A Charger, which uses GaN technology to charge up to three times faster than Bosch's previous charger.
How it works: Once the 12A Charger is available, you'll use this setting to choose between normal and fast charging. For now the toggle does nothing, and your current charger keeps charging at its usual speed whatever the setting.
Who it's for: Smart System owners who regularly need a quick top-up: commuters, cargo riders doing several school runs a day, and tourers recharging over lunch.
Considerations: The 12A Charger isn't in Australia yet. Bosch's Australian distributor has confirmed it will arrive in early 2027. Until then, ignore the setting. If you'd like to be first in line, let us know and we'll contact you as soon as it lands in Milton.
Good News: The Bosch SmartphoneGrip Vertical Has Arrived
The Bosch SmartphoneGrip Vertical is now in stock at our Milton store and ready to order. It turns your phone into a portrait-format eBike display running the Flow app, so navigation reads like a map rather than a letterbox. It charges your phone while you ride (5W wireless or 7.5W USB-C, powered from the eBike battery). It's IP55-rated, uses a dual-clamp design that stays put on gravel and rough surfaces, and fits phones 135–170mm long and up to 260g including the case. It suits Bosch Smart System eBikes with a 1-arm socket.
Prefer landscape, or have a Purion 200 or LED Remote? Check out the Bosch SmartphoneGrip (horizontal) and the SmartphoneGrip Retrofit Kit.
Frequently Asked Questions
Do I need to bring my bike in to get the 1.38 update?
No. Update the eBike Flow app on your phone, then install the bike's software update over Bluetooth from the app's home screen. Keep the bike still and don't remove any components while it installs. If the update won't install or a feature doesn't appear, our Bosch-accredited workshop in Milton can check it with dealer diagnostics.
Why can't I see traction control or Drivetrain Tensioner in my app?
Both features are only available on the current-generation Performance Line CX, CX-R and Cargo Line motors. If your bike has a Performance Line, PX, SX or Active Line motor, those menus won't appear. Not sure which motor you have? Our Bosch eBike Brisbane guide explains every motor in the range, or call us on 07 2102 9775.
Set It Up With Us in Milton
Want help dialling in traction control and Drivetrain Tensioner for your riding, or fitting the new SmartphoneGrip Vertical? Let us know when you book your next service and we can show you.Â
