Tripod load capacity question

I do very well understand the "load capacity" for the ball head that you put on as it will actually need to hold the gear.
However I am bit confused as to how does the same work with the legs. (Especially those w/o center column)
Many times you see the recommendations to hand you camera bag/sand bag or some such thing to the bottom of the center column to stabilize the tripod. Which also means more the weight (to a limited extent) you put on tripod, the stable it is.
Then why the legs have to be rated say 15 lbs load capacity.
If I put 20 lbs of gear on it, wouldn't it be more stable?
In which case should your legs be rated 2 or 3 times the gear you are going to put on it?
Again this is when center column is not in picture as it could be the weak link in the whole equation..

The problem with the "load capacity" specs that are advertised for tripods and heads is that there is no standardized test to produce the numbers that marketing people put into their advertisements. Manufacturer A might have a tripod/head rated at 15 pounds load capacity that is very flimsy and would crumble with just a little more weight on it and Manufacturer B could have another tripod/head rated at 15 pounds that holds a 15-pound load quite steadily with no risk of disassembly. There is absolutely nothing that I am aware of that creates any uniformity for these reported ratings.

rndman wrote in post #15607896
I do very well understand the "load capacity" for the ball head that you put on as it will actually need to hold the gear.
However I am bit confused as to how does the same work with the legs. (Especially those w/o center column)
Many times you see the recommendations to hand you camera bag/sand bag or some such thing to the bottom of the center column to stabilize the tripod. Which also means more the weight (to a limited extent) you put on tripod, the stable it is.
Then why the legs have to be rated say 15 lbs load capacity.
If I put 20 lbs of gear on it, wouldn't it be more stable?
In which case should your legs be rated 2 or 3 times the gear you are going to put on it?
Again this is when center column is not in picture as it could be the weak link in the whole equation..

Putting the weight below the head lowers the center of gravity, making the setup more stable. Putting it on top does the opposite

nma wrote in post #15608454
Putting the weight below the head lowers the center of gravity, making the setup more stable. Putting it on top does the opposite

Yeah. That makes sense..

SkipD wrote in post #15608152
There is absolutely nothing that I am aware of that creates any uniformity for these reported ratings.

You would think Consumer Reports would have done something in this area but I guess not.

peter_n wrote in post #15609178
You would think Consumer Reports would have done something in this area but I guess not.

They couldn't figure out how to do meaningless tests on it.

Consumer Reports is poor on assessing technical merit characteristics...it would tell you a VHS video cassette recorder is a 'best buy' simply because they are less expensive than Beta and they could record up to 8 hours on a tape. They would fail to understand that image quality is far better with Beta, and that 8hour image quality sucks. But JVC's aggressive marketing to the companies make VHS cheaper to manufacture, and Consumers rates on 'value'.