During the early years of the Advance Design trucks there were many complaints by new owners about the rear bumper. They didn’t want it as standard equipment. Farmers and businesses could not get close to a dock with a bumper and they removed them soon after the truck purchase. Dock workers and live stock could step in the open slot created between the dock and truck bed. No doubt sprained and broken legs were, at times, a result.
Thus, in 1951 GM ceased placing a rear bumper on pickups as standard equipment. Before this, the rear bumper had nicely protected the under bed spare tire hanger from minor collisions.
Without a bumper the manufacturer was forced to redesign the spare tire assembly. It became suspended from the frame of the truck at an angle. The truck could now receive at least a parking lot collision without damage to the spare tire assembly even without a bumper.
An item of interest: The ½ inch hole in the middle of the rear cross sill that holds the spare tire hook on the 1950 and older pickups was no longer used beginning in 1951. However, the manufacturer continued to place this small hole in the sill through the 1953 year! (In this 1951-1955 photo the eyebolt in this hole is an owner installed add on.)
The two cross chains in this photo are securing the truck to the trailer and are not part of the spare tire assembly.