Very intersting thread ! I have indeed the same kind of question.
--> I'm thinking about building a long-john cargo bike (26" rear, 20" front), suitable for heavy-duty professional use (heavy loads -up to 150kg payload- and high daily mileage).
For having tried mid-drive motor (BBS01 48V) on my Surly Krampus, the wear of the transmission was already problematic depiste good-quality components. I cannot imagine with a cargo bike and a BBSHD. Perhaps with a Rolhoff + belt (the kind of setup found on high-end Riese&Muller cargo bikes) ? In addition, with a mid-drive there is no regen braking and I guess the wear of brake pads on a cargo bike must be quite huge.
I currently have a GMAC on my ebike, which I like. But for a cargo bike I prefer the idea of front direct drive motor : 2 wheels drive (muscular rear, electrical front), 20" wheel well-suited for hub motors, no maintenance apart from bearings replacement from time to time. And this also :
kevinscargobike said:
What I grew to appreciate about the hub motor from a bikey POV is that I really liked that the bike drivetrain is just for me and I never have to shift because the motor needs it.
What would be the best setup ? Frankrunner/Phaserunner for the controller, but I'm hesitating between the Grin All-Axle and the RH212 (or else ?)
On 25% grade with 500 lbs all-in and 300 watts peak pedaling power, the RH212 is slightly more efficient :
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=25&hp=300&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=300&grade_b=25&bopen=true
And the BBSHD is more efficient than the RH212 (but it overheats as quickly) :
https://ebikes.ca/tools/simulator.html?motor=9C212_7.5T_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=25&hp=300&cont_b=FR&motor_b=MBBSHD&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=300&grade_b=25&bopen=true&autothrot_b=false&autothrot=false&throt=100&throt_b=100&mid_b=true&gear_b=1&tf_b=42&tr_b=30
On 7% grade @100 watts pedaling power, the RH212 is also slightly more efficient:
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=7&hp=100&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=100&grade_b=7&bopen=true&autothrot_b=false&autothrot=false&throt=44&throt_b=36.7
On flat terrain, the Grin has a better efficiency :
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=0&hp=100&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=100&grade_b=0&bopen=true&autothrot_b=true&autothrot=true&throt=6.8361606833450805&throt_b=5.994712603576505
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I would be inclined to choose the Grin, because it is all-axles compatible (I'm not found of the standard axle setup (i.e. not thru-axle) for hub motors, it damages the dropouts and is not as clean as a thru-axle setup), and it's made by Grin in Canada.
Your thoughts ?
Another question : on wet roads and driving an empty cargo bike, can the front hub motor be more difficult to handle than a rear hub or mid drive in terms of grip ?