I live for the CABE
In my opinion, the problems at the time were much larger than just figuring out what "bead size" size tires to "spec" on the three speed lightweight model. The entire market demand had already left the 26" lightweight size and moved on to the higher air pressure, lower rolling resistance of a 27 x 1 1/4 wheel size. For that matter internal geared hubs were on the way out also. They were heavy and expensive to manufacture. Bendix was phasing out of the Kick Back Automatic's, Sturmey Archer and Shimano three speed hub models were becoming less popular on the sales floor. The lightweight 27" derailer equipped models were selling well. Even in ladies fenderred models like the Suburban, the five speed was a better volume seller, and at a higher price. The Racer, Breeze coaster brake and three speeds ended as Chicago was slowly closed down. These models were replaced with imported models from Giant, and later CBC with 26 x 1 3/8 EA-3 bead rims. So the entire rim bead sizing issue was over except for the "aftermarket parts replacement business". Obviously, from this conversation the sizing issue and availability of quality replacement tires are still a PITA even today, decades later.Those are good catalog pages. With the EA3, the spoke counts are interesting. With the 32-40 spoke count options, it becomes a way of enabling the use of higher-end British hubs on the Schwinn bikes. And the 36-hole EA3 would enable use of Schwinn wheels on a British bike. The EA3 size also broadens the array of tires, especially after the mid-1950s. I find the time period of these catalogs interesting in that the higher-end British road and club bikes moved from 26x1-1/4 to 27x1-1/4 more and more over the course of the 1950s, whereas the EA3 tires remained much more commonly available. You had Schwinn tooling up for EA1 production in the S6 rims in the late 1940s, but within just 10 years, the British were replacing that size on many of the sportier bikes with 27 inch.
I wonder if there was thought given at Schwinn to abandoning the EA1. As a manufacturer, was there concern that EA1 was a dead-end size in terms of quality tires, with the gradual abandonment of that size for club bikes in Britain? We all know how it ended up... several options today for EA3 and just the one for new EA1 tires...