My younger son's friend and his Dad & brother invited us down to the local school for some fun this afternoon. Mark builds these himself from parts sourced and custom engineered for way less than the commercially built units. Lots of fun...I had a go, and they are really cool to throw around on the seal. Motor is in the front wheel - 1000W hub on the smaller trike, and 1600W on the larger. The rear go-kart tires spin free, and are over-sleeved with PVC tubing (drain pipe) to allow for the sliding. Heaps of fun.....with lots more to come now that Summer has arrived. 
