I have a set of that size radials on original 4.5" 1954 rims, but they have tubes (they might not need tubes). These have had no problems in 8 years (under 10,000 miles.
I plan to mount another set of the Cooper SRM II 215 85R16 LT tires on another set of original 16x4.5 rims that were in excellent shape and have been "trued" for balancing and powder-coated. I will try these without radials - if they leak, I'll again use radial inner tubes.
The rims are not too narrow. The narrowness of the rim results in two related benefits (as far as I am concerned): a higher profile that looks more like a bias-ply tire; and, a loaded radius of about 31.5" (resulting in about a 10% decrease in RPMs). This put no significant strain on the sidewalls.
