A quick update.
I had to change the tires of my wheels, the o-ring I meant to use had a diameter of 40 mm and I changed to one with a diameter of 45 mm instead.
New wheel diameter increased the top speed from 10 km/h to 11,5km/h 😎
I've been doing a lot of work since last time and there have been some changes in the design as well!
After I assembled a couple of parts in FreeCAD I realized that I had miscalculated (in my head) the size of some of them 🙁
I had to flip the base plate upside down to make room for the steering cradle and remove the friction wheels, because they wouldn't fit anymore. I also had to make the propel wheel larger to get better grip and to make the ball go a bit faster.
The approximate speed is now somewhere about 10 km/h, which is a quite good speed I think.
The base plate front view - with motors and steering craddle and its servo