So, I've been attempting for about a month now to locate a sprocket that will fit the shaft of the Golden Motor 5kw or the 10kw setup. It's not the hub motor, it's these:
48 Volt 5000 Watt Brushless DC Motor (Golden Motor)
48 Volt 10000 Watt Brushless DC Motor (Golden Motor)
Model: HPM5000B...