You have already answered the first question yourself in the 3rd paragraph. The setup is only as strong as the weakest link. Just bear in mind that the load rating provided by the manufacturers always have a safety margin, so that the tripod will not just collapse if you put 2.6 kg on it.Originally Posted by ivor
I don't understand the question in your second paragraph. Did someone make a claim that a tripod rated at 2.5 kg load can withstand a 6.5 kg actual load when fitted with a 6.5 kg rated ball head? Can you provide the reference to that claim? If not, then this question has no basis. Even if someone made that claim, it should be clear that such a claim is not valid.
Just calculate the total weight of the equipment that you need a tripod for, and then compare that with the rating of the tripod and ball head. The tripod should be able to take the weitght of the equipment plus the weight ofthe ball head, and the ball head should be able to take the weight of the equipment.
If the load exceeds the manufacturer's specifification but only marginally, the best is to try it out at the shop before you buy. As I said above I don't think in such a case the tripod would just collapse under th increased load, but it may start to loose stability as the load increases because of the higher centre of gravity of the whole setup.
If this thread degrades into a follow-up debate from Terence's sales of his tripod and ballhead, I will close this thread immediately.