Rumba robot replacement wheele

I have an old Rumba Robot 760 and it's front wheele became useless because of the wear. The robot wasn't  anabled to reach the dock. 
So with my caliper I took all the dimensions and I made my CAD model .
It works well, and I made two versions :
One needs a steel shaft (4mm) as the original while the other version has a plastic shaft.
more information download and other projects on my website :

https://www.notale.org/rumba-whelee