The 26 x 1-3/8 x 1-1/4 S6 tires were used on vintage Schwinns like the Breeze(pictured), Racer, Traveler, Speedster and Collegiate.
Some Older British Club bikes use this size, designated 26 x 1 1/4 EA.1
This tire has a slightly larger diameter than the Raleigh (590) tire.
Straight 'Ribbed' Tread.
Available in all black or black with gum sidewalls.
Don't assume your old Schwinn 3-speed needs the Schwinn sized tires.
Some Schwinn 3-speeds have had the Schwinn wheels replaced with the more readily available 26x1-3/8 EA3 (590) wheels.
Whenever possible, check the size marked on the existing tires:
Schwinn = 26x1-3/8x1-1/4 S6 (597)
Raleigh = 26x1-3/8 EA3 (590)