Weight load on closed tailgate

I’ve some past threads on weight limits on an open tailgate, but is there any general idea how much weight the tailgate can support when closed? As in, how much can I load on top of the tailgate if hauling something that’s longer than bed. Realize I could lower or remove tailgate and use straps, but just curious since I’m looking at some metal shelving that weighs a couple hundred pounds. Would be easiest to load by just sliding in and resting overhang on top of closed gate.

 

Answer depends.

How long are the shelves? 8-10ft = no problem. >10 ft = use a trailer or have delivered.

If this were me, assuming <10 ft.....I'd open the tailgate. Spread the load across the bed width. Secure the load with ratchet straps. Tag a red flag on the shelf ends hanging out.

 

I would consider it insignificant.
The front end of the shelving sits on the bed - about half the total weight of the shelving.
What's left is bearing on the top edge of the tailgate - not likely to cause any problem.
Or, as Knute says:

I have carried multiple loads of 10' & 12' lumber with the tailgate up. Works out well because I can use a load binder inside the bed across the 2 rear tie-downs. Secured like that, the front end of the lumber can't bounce upward.

 

I purchased a used warehouse type rack.

2 uprights 7 feet high, 4 feet wide.
6 beams 8 feet long.
wood shelf board and cross members to make 3 full shelves.

I rented a U-haul trailer. They are economical.
The ability to properly secure that load in the back of my truck was a bigger issue that the weight.
Rented trailer was peace of mind.