Originally Posted by Greg_H
16 was standard and 15 was optional...actually, the 15 was I think 1/2" wider.
You'd be correct.

RPO 273, Tire size 15, Ply 6 - Series 3100 (3600, 3700 spare)
and
RPO 282

Source: 1954 Chevrolet Trucks Resto-Pack, RPO Page
(Original Scans contributed by Greg H) Hey that's you wave


1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC