what Eluwak writes I also wrote , that its the responcibility of the tire-specialist, to put tires on that are allowed on the rimms and car.
the maximum load or pressure for the rimm is mostly written on the innerside of the rimm, so you have to take it of the car to read it.
What risks you take if you go over that , I dont know, but people yust as easy go over the GAWR ( gross axle weight rating)wich is also forbidden.
Probably there is some reserve over the pressure or maximum load written on the rimms, yust as it is for the technical axle maximum above the GAWR, but you cant build on that , and cant keep the manufacturers responcible, if something goes wrong because of going over it.