dddd, thanks for the inputs. Some very valuable information.

I have to winder how many people who indicate above that 1¼ inch tires on 14mm gap width rims are ok actually measured the tire width. Notably, an old set of IRC "Road Winner Duro II" 27x1¼ tires that I have on another bike actually measure 27.9mm (1.1 inch) wide at max inflation on 18-19 mm (70's steel Ukairim) rims. I also wonder how many who mention that they have been running the referenced combination are at or near max inflation pressure.