I have a boxful of bits of kits including some old GW vehicles. I think the bit in the top photo come off what is called a Rhino? Anyway I never liked the shape of this vehicle because it always seemed to be to be the wrong way up. So an hour's modelling produced these new track units. The wheels came from old 1/72 Pzr III kits I had in my bits box. I made up 22 sets (11 per side) which I then had to cut in half to make it look as if they are recessed into the hull. Drive sprockets and idler wheels (also from the Pzr III kits) are actually set into the hull. The rubber track is off an old toy tank cut to fit.
I really enjoy using up bits from my scrap box to make something new.
I was after something a bit like the Churchill tank . Will start work on the hull tomorrow. Not sure yet whether I want it to be a tank or some kind of personnel carrier.