The one closest has the 8" wheels the furtherst one looks like its got 7" wheels.
Those autodrives with no teeth, I had them on something here a while back. MrDavis was going to try and sort out the what and the why with that one.
Personally I think they fit in somewhere between the large centre cap moulded/solid rubber and the moulded plastic treaded wheels.
The moulded rubber large cap wheels is what that should have on it. Front and back.
