The mid-1947 upgraded KBR-12 continued with the same basic 28500 lb GVW rating and 55000 lb GCW rating as the KR-12. In 1948 International advertised GVW ratings up to 35,100 lb and GCW ratings up to 66,000 lb for ideal conditions. In 1949 the basic GVW rating went up to 31,500 lb. Also in 1949, the KBR-12 with its Timken U200 double-reduction rear axle was joined by the KB-12, with a Timken R100 hypoid single-reduction axle, and the KBS-12, with a Timken U300 2-speed axle. A few KBD-12 trucks may have been built with Cummins 6-cylinder diesel engines.