Bafang M510 vs M620 Ultra: which mid-drive to choose in 2026?

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

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.

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

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

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