My rev1 placard states 87 on the rear. My 235/40/17 federal 595 Rs-r is 90 rated. However I did have trouble with the fronts as in a 215 theyre only 83 and theyre supposed to be 85. I put this down to the type of tyre and the compound where they would get too hot under load. FWIW my old cheap fronts were 87 in the same size.
Also if you look at the actual kg rating of 83 for eg they still will support much more than the front end of an sdub will give them.