While the first production F-86s were under construction, North American's team was also working on a USAF requirement for a Sabre with larger landing gear tires that would be suitable for rough airfields. This at first sight sounds like a fairly simple and straightforward thing to do--what could be easier, one might ask, than for designers simply to increase the size of its landing gear tires? However, as is often the case, this turned out to be one of those requirements which had far-reaching implications, needing many more changes than one might initially think--larger tires required larger wheelbays which in turn required a seven-inch wider fuselage in order to accommodate them. Change one small thing and you end up having to redesign the entire airplane :-)
These larger-wheeled aircraft ended up being so different from the production F-86A that they were designated F-86B. However, the development of higher-pressure tire designs and better wheel brakes eliminated the need for larger tires, and North American recommended on December 1, 1946 that work on the F-86B be discontinued and that the contract for 190 F-86Bs be transferred to an order for 188 F-86A-5-NAs and two F-86Cs. This proposal was accepted by the USAF, and on December 16, 1948 the F-86B was officially cancelled.