Hello! I believe that you need to consider the material you want to print this model from, the tolerance of your printer, the quality of the roads and of course how loyal a driver you are. Initially, the model was not planned for transporting something large and heavy, as I described in the description. But nevertheless, once there was an overload due to a pile of stones that my daughter had collected there and the anchorage simply became detached. But nothing was broken, we just connected it back together. I think there was over 3-4 kg, but it’s hard to say. Therefore, I suppose a package of milk and bread, one of each, should hold up. Otherwise, the fastening holder and locker needs to be revised and strengthened. Of course, you can conduct tests, and if the result is negative, then let me know, I will try to take the time and think about strengthening it. Good luck!