its just a small hack but maybe someone is interested in it or can use the trick:
I started working on a lawn robot but didn`t find any usable tire. While playing with my daughter with an Oball i formed this one so that i got something like a tire.
Than i put some old lego rims on the oball holes and they fit perfectly!
After that i attached all on a dc motor and it works fine.
The next step is to test them on a robot platform.