[Mattias]

I use Associated spur gears with Associated slipper pads. "All" I had to do was to grind the flat bits of the shaft a bit (2-3 mm) longer, and use the inner ring from a ball bearing pressed into the spur gear to convert from 4,8 to 4 mm inner diameter. Works a charm, even if the actual slipper area is a tad small. I run a 13.5 motor, so I don't think it will stress the slipper too badly.