In 1949/50 (and maybe earlier), the Advance-Design Chevrolet 1/2 ton trucks' standard wheels/tires were 6.00-16, 6 ply on a 16x4.0 rim
In 1949/50 (and maybe earlier) the Advance-Design Chevrolet 1/2 ton trucks had three different 15" wheel/tire options:
RPO 288B 6.70-15, 6 ply on a 15x5 rim
RPO 273H 15"-6 ply on a 15x5.5 rim
RPO 280F 15"-8 ply on a 15x5.5 rim
In 1954/55-1st, the Advance-Design Chevrolet 1/2 ton trucks' standard wheels/tires were 6.00-16, 6 ply on a 16x4.5 rim (6.50x16, 6ply on a 16x4.5 rim was available as a common option on the rear-only or on front and rear)
In 1954 the Advance-Design Chevrolet 1/2 ton trucks had one 15" wheel/tire option:
RPO 273K 15"-6 ply on a 15x5.5 rim
Some, if not all, 1947-55 1/2 ton New Design GMC trucks also had 6-bolt 15" rims available, but I think they used a split rim.
