The kobuki foundation by yourself would not drift, so it is smart that the tilted inertia will cause the drift. Not surprisingly I am able to hack my URDF by using a weightless superstructure, but I needed to take care of this in a more real looking way. I tried https://www.uk-exhibitionstands.co.uk/5-display-stand-hacks-to-make-your-exhibition-stand-pop/