A roof rack is usually used to carry more things in addition to the roof tent. The roofrack is usually bigger than the roof tent.
Are you going to make your own roofrack or does your car have a self-made roofrack? Make sure there is enough distance between the beams and the roof. You need at least 5 cm to mount the roof tent. Otherwise you can't reach it with your hands and tools. (Grey number plate roof of a defender is such an example that you have no space between the roofrack and the roof to work on).
If you have a brand roofrack we always advise to use roofrack raisers to mount the tent easily. Mounting the roof tent directly on the roof rack without the raiser is sometimes possible but makes mounting very difficult as some roof racks have raised edges. The raisers also make it much easier to open and close the cover.
