The data stated in the "Results" table under "Sidewall Height" is not reflective of the diagram.
The diagram is depicting a "Sidewall Height" as measured from the edge (O.D.) of the rim to the tread plane.
For ex: our 21" turbine "real world" sidewall is not 3.38" but a measly ~2.25"
27.75 (tire OD) - 22.50" (wheel OD) / 2 - .375" (compressed distance due to weight of car) = ~2.25"
The table above is measuring from inside the wheel at the 21" bead surface to obtain a meaningless (to me) 3.38"
A ~2.25" sidewall will barely handle a sharp bump let alone a pot hole of approx. 2" deep before the edge of the rim will sustain a deformation often along with pinched/cut/bit sidewall.
Btw, the inboard side of the rim will bend much easier upon a slight impact since it is not directly supported.
Just say NO to 21's !!