The kobuki base by yourself would not drift, so it is smart that the tilted inertia brings about the drift. Needless to say I can hack my URDF with a weightless superstructure, but I wanted to fix this in a far more reasonable way. I tried all I am able https://www.uk-exhibitionstands.co.uk/product-category/light-box-displays/casonara-light-box-walls/