Why is it in VR I see no rear tyres on open wheeler cars. Is it just a graphic setting that need to change or is it the mod?
You might be able to see them if you enable show self in rear view. The whole system was setup before VR, probably before it was ever even thought about, so that's why you don't see them. The game probably needs a new line in the cockpitinfo.ini file for rear tires now that we are able to see them.
As @Coutie says a lot of Pre-VR cars have missing areas when you turn around, hopefully New S397 cars from now on should show everything at default.