The kobuki base by yourself would not drift, so it makes sense that the tilted inertia causes the drift. Needless to say I'm able to hack my URDF by using a weightless superstructure, but I planned to deal with this in a far more real looking way. I attempted all https://www.uk-exhibitionstands.co.uk/product-category/pop-ups-and-banner-stands/pop-up-display/