I am going to build storage for tires under the roof of the carport. I'm considering attaching crossbeams to the visible rafters 70x195 using some kind of spacer so that the storage depth becomes about 230-240mm, allowing the tires to fit. On the crossbeams, I plan to attach 4 spruce plywood with hinges that fold down, and on these, I attach a holder for the tires before the hatch is lifted and closed with a latch and secured. Any tips or ideas anyone?