Grey Fergusons

Old GM, read back a few posts where you'll see she ended up with a broken off mill roller shaft on the arse end. That was approx 2' round solid steel about 3' long, courtesy of Gin Gin mill's scrap yard.
Guess that photo was day one, planting time so would have been May?? By crushing time I can assure you she was counter weighted.
As for water ballast tyres, we all did it back then, didn't know any better.
Some great reading from Cat on that subject which shows how much fuel we must have wasted all those years of using water ballast instead of fixed wheel weight ballast.