Pimping up my Snow Beast.
Oem is 24V 450w with a 15-16mph top speed.
Regearing, by replacing the 20T motor side freewheel with the 16T provides an enjoyable "legal" ~20mph that appreciates pedal assist.
Adding 25.9V battery pushes the MY1018z motor just past 20mph and the XYD-16 motor right to 20mph.
Revolting to 36V pushes to ~23mph (past legal) and pumps watt output to near legal 750w limit.
Built large 33.3V battery with recycled cells which dropped speed near 20mph and enjoyed great range, but LVC on the upgraded 36V controller kicked in too early, especially in the cold.
Got a supply of 36V HO hoverboard batteries so adapted for Snow Beast use with good torque and excessive speed.
Had to rebuild motor wheel, so decided to fix things "proper".
Latest SB upgrade involved Gearing motor wheel down from 20T to 22T with the 36V upgrade.
Near ideal! With battery partially charged, (for greatly extended life), bike humps right up to 20mph and only drops to 18mph on reasonable hills.
Final perk will be upgrading the 36V 25A to a 36V 35A controller. This will not increase speed but will pump up the motor towards "legal" 750watt output limit and improve acceleration and steeper hill capability nicely.
Snow Beast motor is the sacrificial lamb for testing this set-up. Having survived 6000+ miles and 10 Winters of salt, snow and slush, at worst, will go out fighting!