- Control-board Overheating: if the Wheel was pushed at all, the temperature would quickly rise, forcing the Rider to dismount
- Width: at over 8″ wide, it was short & stubby, not the most comfortable stance to ride in
- Design: it was frequently accused of being a bit of an ugly duckling
- Durability & waterproofing: it’s main weakness was that motor axle that was used had a tendency develop hairline fractures which degraded over time. The water-protective measures were not very good at all
The King Song Engineering team built on the lessons, of the brilliant but flawed 14C, to create the 14D/14S line. It’s now equipped with a larger heat-sink & active (fan) cooling to dissipate unwanted heat build-up during high intensity operation; in the case of the 14D, the Wheel is 2″ thinner; is beautifully sculptured & now has the all important retractable handle alleviating the need to lug it around. On the durability side, there are dozens of small improvements that are almost too numerous to mention, better screw holds, thicker shell; but for durability, the most important improvements are probably the ticker axle & better pedals.