The Bafang context in 2026
Bafang equips a large portion of e-bikes assembled outside the major brands (Cube, Trek, Specialized remain with Bosch/Shimano). For an independent frame manufacturer or assembler, the choice is made almost systematically between M510 and M620 Ultra. Two very different philosophies.
Comparison table
| Criterion | M510 | M620 Ultra |
|---|
| Max torque | 95 Nm | 160 Nm |
| Peak power | 500 W | 1000 W |
| Nominal power | 250 W | 250 W (legal EU) |
| Weight | 3.5 kg | 5.4 kg |
| Max assisted cadence | 100 rpm | 120 rpm |
| Torque sensor | Yes (12 bit) | Yes (12 bit) |
| Connectivity | Canbus + UART | Canbus only |
| Crankset | Square 68/73 mm | BSA 68/73 mm |
| Waterproofing | IP65 | IP65 |
| Motor price alone | ~600 € | ~950 € |
For which use?
M510 → urban, trekking, gravel. The 95 Nm is more than sufficient for urban climbs and country paths. The 2 kg saving on the overall bike is felt immediately when pedalling with no assistance (battery off or flat). It's the default choice for a versatile e-bike under 4,000 €.
M620 Ultra → heavy enduro, cargo, long distance. The 160 Nm is necessary to pull a trailer, climb steep terrain in boost mode, or compensate for passenger weight. The 5.4 kg, on a cargo bike weighing 35 kg, is barely noticeable. The motor also runs cooler under sustained effort (greater thermal mass).
The less obvious differences
Noise
The M510 is notoriously quieter than the M620. Whine at 35 dB in comfort mode (M510) vs 45 dB (M620). On a commute, it's noticeable.
### Programming
Both accept programming via the Bafang Config Tool software (USB OTG). You can adjust:
- Torque curve per assistance level
- Cut-off speed (limited to 25 km/h in EU)
- Assisted start (slow / progressive / aggressive)
The M620 has a tuning range 2× wider than the M510. For an installer or workshop that customises, this is a selling point.
Battery compatibility
| Motor | Voltage | Current capacity |
|---|
| M510 | 36 V or 48 V | 500-700 Wh |
| M620 Ultra | 48 V only | 700-1000 Wh |
If you're considering a future upgrade to a high-capacity battery, the M620 is more flexible (standard 21700 cells).
Known defects to watch out for
M510
- The torque sensor begins to lose precision after ~15,000 km — phantom assist on cold starts reported on certain units
- No walking boost mode (6 km/h) — software limitation
- UART connectivity deprecated, Bafang pushing Canbus
M620 Ultra
- Possible overheating on steep climbs sustained (>15% for +20 min) — motor drops to degraded mode at 80°C
- Aluminium casing fragile to side impact — consider a protective skid plate if serious MTB use
- Error code display cryptic without Bafang documentation (not public)
Recommendation by profile
| Use | Choice |
|---|
| Daily urban e-bike | M510 |
| Long-distance trekking | M510 |
| Gravel e-bike | M510 |
| All-mountain MTB | M620 Ultra |
| Cargo bike | M620 Ultra |
| Heavy child trailer | M620 Ultra |
| Speed Pedelec (>25 km/h) | M620 Ultra (with adapted programming off public roads in EU) |
Got a question on Bafang programming or motor choice for your project? The mechanic AI cross-references Bafang manuals and the community database to answer you precisely.
