Climbing hills on a converted e-bike requires torque, not just raw wattage. Here's why mid-drives beat hub motors on hills, and which specific kits we recommend for serious climbing.
If your commute or recreational route includes real hills ā anything over an 8% grade ā your motor choice matters more than any other spec on the spec sheet. Wattage alone is misleading here. A 1000W hub motor will struggle on a 12% grade while a 500W mid-drive glides up the same hill. The difference comes down to torque and gear multiplication.
Torque is what turns your wheels. Wattage is just how fast that torque is delivered. A mid-drive motor drives through your bike's chain and gears, so when you drop into a low climbing gear, the motor's torque gets multiplied by the same gear ratio your pedaling does. A 100 NĀ·m mid-drive in a 1:3 climbing gear effectively puts 300 NĀ·m at the rear wheel. A 1000W hub motor has no such multiplication ā it's stuck at whatever torque it produces at the wheel, period.
For real hills, you want a mid-drive. Here are our specific recommendations, ranked by climbing ability.
Our Picks
BAFANG BBS02B/BBS-HD Mid Drive Kit (750W/1000W)
ā ā ā ā Ā½ 4.6- Power750W / 1000W
- Voltage48V / 52V
- Torque120-160 NĀ·m
- Price$399 - $549
The industry benchmark for DIY mid-drive conversions. The BBS02 (750W) is the sweet spot for power and reliability; the BBSHD (1000W) is the bulletproof choice for hardcore builds.
Varstrom 48V 750W TSDZ8 Mid Drive Kit (1056W Peak, Torque Sensor)
ā ā ā ā Ā½ 4.5- Power750W (1056W peak)
- Voltage48V
- Torque120 NĀ·m
- Price$429 - $549
The new TSDZ8 fixes everything the TSDZ2 lacked ā more torque (120 NĀ·m), more peak power (1056W), better cooling, and a color display. Best torque-sensor mid-drive value on Amazon.
BAFANG 48V 750W Mid Drive Kit with Battery & C18 Display
ā ā ā ā Ā½ 4.5- Power750W
- Voltage48V
- Torque120 NĀ·m
- Price$599 - $799
Same great BBS02 motor bundled with a matched 48V battery and C18 display. Saves you the headache of sourcing a compatible battery separately.
Climbing Math
Here's the practical climbing math, assuming a 175lb rider on a 40lb bike with a 48V 15Ah battery.
5% grade (gentle city hill): Any 500W+ motor handles this comfortably. Even budget hub motors manage 15mph.
8% grade (moderate hill): 750W mid-drive maintains 15-18mph. 1000W hub motor drops to 10-12mph. 500W hub motor struggles to maintain 8mph.
12% grade (steep hill): 1000W BBSHD maintains 12-15mph in low gear. 750W BBS02 manages 10-12mph. 1000W hub motor is barely moving at 6-8mph and overheating.
15%+ grade (very steep): Only mid-drives need apply. BBSHD does 10-12mph. BBS02 does 8-10mph. Hub motors will overheat and trigger thermal cutoff within a minute.
If your route has anything steeper than 10%, buy a mid-drive. Period.
Final Thoughts
Hills are unforgiving ā there's no faking your way up a 15% grade with marketing watts. Get a real mid-drive with real torque (the BBS02 at minimum, the BBSHD if you can afford the weight), pair it with a 48V 15Ah+ battery, drop into your lowest climbing gear, and you'll be passing road cyclists on the way up. We promise.