12" x 4" Pneumatic Wheel 5/8" Axle Use For Hand Truck Wheelbarrow ETC. 1007
Inflate to 30 psi do not exceed 40psi
13 x 5.00-6
Nylon tube type
Not for highway service
Off-set hub
Total width of hub and offset shaft is 5/8" x 2-1/2"
The hub is approximately 7" in diameter.
The shaft is approximately 1-1/2" in outer diameter and 5/8" interior. Depth or length is approximately 2-1/8"

Many of the wheels have some surface rust especially at the bolt area. (see pictures)  It does not affect the performance of the wheel.
inkFrog