For hub motors, the torque is measured at the motor wheel. The maximum gradient that the motor can cope with is inversely proportional to the wheel's diameter. The maximum obtainable torque is measured when the motor is near stalling and depends directly on the controlller.
The SWX can give about 25NM with a 14A/15A controller, 30NM with a 17A/18A controller.
The BPM can give about 40NM with a 15A controller, 50NM with a 20A controller.
For a crank drive motor, it is measured at the chain ring. BBS01 15A 250W motor can give 60NM. To compare the BBS01 against a hub motor such as the SWX motor, you need to multiply that figure 60NM by the number of teeth on the rear cog and divide the result by the number of teeth on the chain ring. For example , if you select 14T rear cog (gear No 7 on most 7-speed shimano freewheels), the effective torque is 60NM * 14T / 46T = 18.3NM, totally unsuitable for hill climbing but great for high speed light assist. If you select 34T cog at the rear (gear No 1), effective torque is 60NM * 34T/46T = 44.3NM, the BBS01 is better than the SWX but not as good as a BPM with a 20A controller.
Similarly, the BBS01 18A 350W can give 72NM max, the BBS02 25A 500W can give about 90NM-100NM. On 46T/34T, 100NM at the chainring is same as 74NM at the rear wheel, it will climb more than twice as fast as an SWX and about 50% faster than a BPM motor.
The GSM is similar in performance to the BBS01 18A 350W, roughly equal to a BPM on hills.
