The context: converting your bike to an e-bike
For €600–1200 (kit + battery), you can transform any bike with a standard bottom bracket shell (BSA 68 mm) into an e-bike. Bafang offers two kits that have dominated this DIY market for 10 years: BBS02 and BBSHD.
Warning: we're talking about kits that are not certified as EU e-bikes. The BBS02 can remain legal under conditions (250 W nominal + 25 km/h), the BBSHD is inherently out of spec. Read the legal section at the end of the article.
Comparison table
| Criterion | BBS02 | BBSHD |
|---|---|---|
| Nominal power | 250–750 W | 1000 W |
| Peak power | 1200 W | 1500 W |
| Max torque | 100 Nm | 160 Nm |
| Weight | 4 kg | 5.7 kg |
| Voltage | 36 V or 48 V | 48 V only |
| Max cadence | 100 rpm | 120 rpm |
| Bottom bracket | BSA 68/73 mm | BSA 68/73 mm |
| Motor cover diameter | 110 mm | 110 mm |
| Gearbox | no | no (direct mid-drive) |
| EU legality when limited | possible | no |
| Kit price (2026) | €450–550 | €700–850 |
Key differences
### Torque — the decisive factor
- BBS02 → 100 Nm: sufficient for urban climbs, hilly commuting, moderate gravel
- BBSHD → 160 Nm: necessary for cargo, child trailers, sustained steep climbs
On flat ground or moderate slopes, you won't feel the difference in normal pedalling. The difference shows on steep climbs or heavy loads.
Heating The BBS02 is known to overheat during prolonged use >75% of its power (for example, long climb in boost mode). Above 90°C internal temperature, there is progressive torque loss. The BBSHD has 40% greater thermal mass and tolerates prolonged effort better.
### Bottom bracket compatibility Both kits require a BSA 68 mm or 73 mm (standard English threaded shell). Incompatible with:
- Press-fit (BB30, BB86, BB90)
- T47
- Italian (rare, 70 mm)
- BMC 89.5 mm
Check your bike before purchasing. If you have a press-fit, you can fit a threaded adapter but that adds €25 and requires work.
Which kit for which use?
| Use case | Recommendation |
|---|---|
| Commute 10–30 km/day, rolling terrain | BBS02 250 W (EU legal if limited to 25 km/h) |
| Fast urban gravel (private land) | BBS02 500 W |
| Light XC mountain biking | BBS02 750 W |
| Enduro / DH mountain biking (private land) | BBSHD |
| Cargo bike (load >50 kg) | BBSHD |
| Child carrier trike | BBSHD |
| Long-distance trekking | BBS02 750 W (balance of weight/power) |
| Speed Pedelec at home (>25 km/h, private land) | BBSHD |
