nomerok who knows what kind of design this is on the wheel?
In Brazil it is known as "rodas raiadas", or you can find it as "spoke wheel truck", in English. It's more common to find in hot weather countries, because this design allow more air cooling. It's common to find this kind of whells in the older time trucks, manly 60's,70's and 80's.
In the image above there is a comparison between the two most selling types of trailer wheels in Brazil. One of the them is the "roda raiada". Image from: https://mundodospesados.blogspot.com/2013/12/roda-raiada-ou-roda-disco.html?m=1.
Oh, now I understood what you were talking about . In Brazil it's known as "rodoar". The function of this thing is keeping the tires with the correct air pressure. It uses the truck air system.