At the "GM PDF file" link posted by Bill:
http://chevy.oldcarmanualproject.com/chevyresto/54159.htm 1954 Chevrolet Truck Specifications Manual
1954 Chevrolet 3100 truck tires/wheels/rims
6.00 x 16" - base wheel/tire (4.5" rim/wheel)
6.50 x 16" - RPO 282 (4.5" rim/wheel)
15"-6" - RPO 273 (5.5" rim/wheel))
