8P: 18″ and 40mm = frequent mounting!!

Hello! Have since last Wednesday the AEZ Zeus rims in 8.5×18 ET 40 with 225 tires on my 8P. Plus the 40mm KW springs. This all on the ambition chassis. Looks strong, but… Well, yesterday I drove with parents and grandma out of food, with as good as empty tank. 3 people, no problem, than my grandma once put the rear tires on the wheel boxes more often. Bzw they cut at the wheel boxes, that is wiser formulated. Weight of the occupants I estimate with the 4 people on about 300kg. Maybe also what less, no idea how hard my grandma is *g* On the way back I filled the car then still full, were almost 50kg, and there it was then completely out. Am the rest way to the grandma with 40 km/h driven, and at every wavy ground unevenness the wheels slid in the wheel boxes. Even after grandma had retired, so the wheels shuffled a few times in the wheel cages or the wheelboxes are still normal? Have you got to look for the wheelboxes?