Bosch’s eBike Flow 1.38 update, announced on 12 October, adds more control over how compatible motors deliver assistance. For UK riders heading into wet autumn trails, the useful question is whether their exact drive unit supports the settings.
Check the motor code first
Bosch’s developer release notes list Performance Line CX-R BDU386Y, Performance Line CX BDU384Y and Cargo Line BDU384Y for both adjustable traction control and Drivetrain Tensioner. A CX badge alone is not enough to establish compatibility.
Four traction-control settings
Under Custom riding modes > Advanced > Traction control, riders can choose off, low, medium or high for each mode. Bosch says the feature regulates motor torque to help limit rear-wheel spin.
Our take: this is a setting to compare on familiar terrain, not a promise of grip on every wet root. Tyre condition, pressure and rider input still deserve attention. Change one setting at a time so you can judge what actually helps.
Drivetrain Tensioner becomes a choice
The tensioner preloads the drivetrain to reduce pedal free play. It can now be enabled or disabled per custom riding mode. Bosch says it is off by default in all modes, so check the app rather than assume your previous setup has carried across.
Other changes
Trick Check gains a screen that retains the last trick’s maximum values until the next trick. Charging-time estimates appear on displays except Intuvia 100; seeing that estimate in the app requires paid Flow+ and a ConnectModule. These features have their own compatibility requirements.
Update the app and follow its bike-update prompts before looking for the new controls. If a setting is missing, check the drive-unit identifier and installed software with your Bosch dealer. We have verified the announcement and compatibility notes, but have not ride-tested this update.
For context, see our Flow 1.36 coverage and Bosch eMTB guide.