BEStie
Hardware compatibility
Three ingredients: a small Bluetooth board, a Bosch Smart System bike, and fitness gear that understands smart trainers.
1. The BEStie board
BEStie runs on any board with a Nordic nRF52832 or nRF52840 chip — there's no hard platform dependency. These boards were tested so far:
Adafruit Feather nRF52840 Express
- Easy firmware updates via built-in USB bootloader
- Battery plugs straight in (on-board LiPo connector) — no soldering
- Acceptable radio performance
Photo © Adafruit Industries
Nordic Dev Kits — nRF52832-DK & nRF52840-DK
- Reference development platform
- Best radio performance (no problems with smartwatches)
- Coin cell battery holder on board
- Flashing requires Nordic developer tools — more setup work
Photo © Nordic Semiconductor
Seeed Studio XIAO nRF52840
- Very small and cheap
- Easy firmware updates via built-in USB bootloader
- Adding a battery means soldering tiny wires
- Weak radio — unreliable connections with smartwatches
Photo © Seeed Studio
For the best first-time experience: Adafruit Feather nRF52840 Express plus a single-cell 500–1000 mAh LiPo battery with a JST-PH connector. The easy installation method is available and no soldering is required. Check the battery connector polarity against the markings on the Feather board and swap the pins around if necessary.
Any other board from this list with an nRF52840 chip works with the same easy method. A generic firmware version that works on any nRF52832/nRF52840 will always be available alongside board-specific ones.
2. A Bosch Smart System bike
Your bike needs the Live Data Interface update (released 4 May 2026), the latest firmware, and an up-to-date Bosch Flow app. Supported motors:
Supported motors
- Performance Line CX Gen 4 (BDU374x)
- Performance Line CX Gen 5 (BDU384x)
- Performance Line SX (BDU314x)
- Other Smart System bikes that work with the Flow app and received the Live Data Interface update
Fitness tracking gear
- Your watch or cycling computer must support a smart cycling trainer over Bluetooth (BLE FTMS profile)
- Rule of thumb: if it works with a Zwift-compatible trainer over Bluetooth Low Energy, it works with BEStie
- Tested by the author on Garmin Edge cycling computers and Garmin Enduro 3 watch; other FTMS-capable devices (e.g. Wahoo ELEMNT computers) follow the same standard
- BEStie can feed two fitness devices at the same time