These shields are all quite small with the biggest one being 24″, which is significantly smaller than even the average roundshield of Battle Brothers (which would probably be about 30″)…
Sorry, but that probably all evidences, that we have. But if you look on that table again, you can see that heaviest steel shileds is about 6kg. And that is mostly parade and ceremonial ones(that page have paragraph that explained why this is so), with all that unnecessary ornaments and other fancy things.
And if you are not satisfied with 22” shields, there is also average density of wooden shields(i dont think that wood changed his qualities since 13th century).
If you do the math for 30”(what is bigger than road velobike’s wheel) and 10mm thick(which is more than enough), you’ll get about 4kg, which is about 1kg more than 22”, and this is a maximum, i.e. worst case – for thick shield and dense wood.
PS Also, i think that you, guys, too fixated on numbers. Try think about, that medieval people were not mad or stupid, they dont carry into battle gear, that they could not effective handle for hours. And also, i’m pretty sure, they had some unpredictable things that could accounted(ones that may prolong the battle, for example).
PPS And, finally, there some points about shields form actual archeologist.
Wooden shields were usually lined with rawhide or leather and has a iron center boss, which increases the weight quite a bit. Neither exists on a smaller steel shield on the 16th century. According to hurstwic, the roundshield weighs 7kg when lined with leather.
“The thin, unfaced reproduction shields shown in the photographs on this page weigh about 5kg (11lbs), while the thicker, leather covered shields weigh more than 7kg (15lbs) when dry.”
Apparently, it was usually made of Basswood, which has a density of only about 300-600 kg/m^3, so if you are talking about purely wood, it would be around 3 kg. But it’s not because it has that metal center piece plus leather which weighs quite a lot to increases the resilience.
The thing is, I feel like you are a bit more fixated with numbers… You seem to think that 10kg is impossible to handle, when in reality the Romans and Greeks did handle shields of that weight in combat, en masse, so we know it’s not something that’s inhumanly. What makes it so medieval people aren’t able to do that? Why would using shields of that weight be mad or stupid?
Furthermore, weight comparison between weapons and shields is not entirely accurate. If you’ve swung a sword before, you’d know that despite the fact that most range between 1-2kg, they do NOT feel that light in the hand, especially when using one handed. This is because of leverage from gravity, which you demonstrated in one of your pictures. Try holding a sword upright, you feel like you’re holding basically nothing… But holding it horizontally feels like you are holding something quite heavy. Shields do not have that problem because they are held upright and are held or strapped in the middle where the center of mass is.
That said, I do agree with a few of your points. I think that some are valid.