The impact of tubing sizes

[IanY]

Reference St. Gobain:

Tygon R-3603 3/8" ID 9/16" OD has a minimum bend radius of 1-3/8"

http://tygon.com/media/documents/S00...3/tygr3603.pdf

Tygon R-3603 3/8" ID 1/2" OD has a wall thickness of 1/16" and has a minimum bend radius of 1-1/2"

Where's this magical tubing that has a 1 inch bend radius ?

{Edit} I see.. 5/6" ID 1/2" OD has a 1 inch bend radius.. so the rage now is to use 5/16" ID (close to 1/4" ID) tubing ?