K123 and W925. What's that mean exactly? Most truck modelers know K100 and W900. I will share with you the info that will help you understand what K123 and W925 means. It's about suspensions, weight ratings and the number of rear axles.
The pix come from K100 brochures of the 1060s. One set is from the 1967 brochure and the other set is from a brochure from about 1965.
Calling the W925 a W925 is incorrect if the kit has the Hendrickson Walking Beam rear suspension. It would actually be a W923. If it has the torsion bar suspension, then it would be a W925.
K121/W921 (4x2) Single rear axle. Spring, air, or torsion bar suspension. K122/W922 (6x2) Tandem rear axles(one is a drive axle, and one is a pusher/tag axle) spring(not sure about air)
K123/W923 (6x4) Tandem drive axles 45,000# GVW spring(Hendrickson Walking Beam or similar) or air K124/W924 (6x4) Tandem drive axles 55,000# GVW spring or air
K125/W925 (6x4) Tandem drive axles 46,000# with torsion bar suspension