Before 1922 when Firestone started manufacturing the balloon tire, trucks ran on solid rubber tires as modeled on this wheel. This type of wheel would have been common on early Mack and other trucks. The Cole Bros. Circus was somewhere on the west coast in 1936 or 1937 when owners, Zack Terrell and Jess Atkins,bought as many as would fit on their circus train and loaded them in every available spot.. Probably got a bargain as the truckers were converting to the balloons. Of course Terrell and Atkins got the last laugh when tire shortages due to WW II caused all sorts of problems for the balloon tire people. The Circus preserved these wheels well beyond their general usage.The wheel was modeled at 3/4 inch = 1 foot. Printed flat on the back side it requires no raft or support. There is a dimple at the center on the back to serve as a starter for drilling an appropriate hole for an axle. Two wheels can be glued back to back representing the double wheels used at the rear, heaviest load, of many trucks.