The KoumKoum, optimized for comfort, easy commuting, ultra-low weight and affordability, is quite unique in several aspects. Its shape, with the wheels around the feet of the user, but also the fact that it is a rollerskate with a chain! From some angles, the KoumKoum looks like a miniature motorcycle!
The chains of the KoumKoum, one of each side of the foot, transmits power from large, efficient and cost-efficient motors, to not too large standard rollerskate wheels, user-replaceable. The chains connect to the motor through a gear-like motor sprocket, and to the wheels through a wheel sprocket.
Until now, these sprockets were 3D printed. Very cheap for quick iteration during the R&D phase, but not strong enough to allow to ride the prototype as fast and on slopes as steep as what the motors are capable of. They also make noise. So, we ordered and finally received CNC-machined metal sprockets.
With metal sprockets, expect us to post videos of the prototype being ridden in much tougher conditions now!
Here is a video that shows how easy it is to service the KoumKoum, to replace the plastic sprockets with the metal ones. Then, the video shows that the chain now runs much smoother.