BPM rear hub motor suitability

[SPYDER]

Living only minutes from Sherwood Pines I seem to be spending more and more time "off-road" just lately and my Xiongda Two speed equipped hard tail is taking a thrashing! Meanwhile, hanging unused on the garage wall is my full-suss full carbon Whyte E120.
The bottom bracket shape of the Whyte precludes the use of a mid motor so I am planning to go with a rear hub type. This must be 135mm max. I am aiming for torque rather than a high top speed.
EV Components are advertising a BPM 48V 500W freewheel motor with a 12 mosfet 25A controller for the princely sum of £54. It bears a winding code of 13 and claims to be 248rpm which seems OK. A little research, however, suggests that claims of this rpm or that rpm mean little when applied to the BPM. "Herrsprocket" on endless-sphere suggests that code 13 will be 230 rpm at 36V and over 300 rpm at 48V. I would put up with that as long as it retains a good amount of torque. My battery is 48V 13.6 Ah with Panasonic cells built by Insat.
The price of the motor is very tempting.
Can anyone with direct experience of the BPM shed any light on its capabilities, particularly its torque at lower speeds. Thanks, Geoff.

 

[sjpt]

I don't have a BPM, but you may get useful figures from https://www.ebikes.ca/tools/simulator.html
Advice from real users probably more helpful but the two together will give a better guide than either separately.

 

[wheeliepete]

That's deff. a good price for a BPM, I'm tempted to get one myself for a future project, although postage nearly doubles the price. I seem to remember reading on ES quite a while ago that code 12 was ideal for good balance between torque and speed, so I don't think 13 is going to be a problem. Being a freewheel motor you will be limited on the number of gears you have to stay within your 135mm dropout, as stretching the frame isn't really an option with carbon fibre.

 

[Nealh]

Code 15 would be better for off road if the going is technical and slow.
Code 13 is better for road and trail riding where speeds are bit quicker.

Not forgetting best use of torque is when the motor is at 50/70% of motor winding speed.