After investigating a bit on the web, i completely changed the design, though i still plan to make the otherone as a light highspeed direct drive version.
The new design is based on a wheel from a big kick scooter and two skateboard wheels, that all have a rill in them.
Power comes from an RC car’s brushless motor with controller. the motor is connected with a small aluminium roll.
Z-axis via rc-sailboat servo that has tremendous power, is quick, with a full turn in 0.7sec and can make 5full turns.
For aditional stability i could add a flywheel.