tire width and rim size

[Biodds]

If you change just the outer barrel to 1/2" narrower, the whole tire will move toward the frame by 1/4". The section width will also decrease by about 0.2 inches so the overall section width would be about 10.9 or 0.1" less per side. So the outer bulge of the tire would move in by 0.25 + 0.1" or 0.35". The inner bulge will move inward 0.25" - 0.1" or 0.15".