Derbi Senda 50 Enduro to Supermoto conversion?

The wheel bearings in derbi bikes are so bad, it's probably the bearing failed putting stress on the spokes.
The bearings quite often fall apart when you take the wheel off.

 

Thank you! I guess this might actually be the problem, since it is totally not normal for the wheel's spokes just to fall apart like that. The repairs-man said that the broken ends might be due the fact, that the previous owner was driving like a mad man, but it just sounded like nonsense, since it's a 50cc bike.
Is there any specific way to check what type of bearings I have to get? Sorry, I'm not experienced with these kinds of things at all.

Edit: Nvm, just found out.

 

You just need to find what size they are and order new ones.
SKF ZZ are damn good.

 

Beautiful! Thank you. Will go to a local motorcycle shop and buy new ones, just as I get the wheel back.