Below is a verbatum copy of a letter in the December 6 issue of Old Cars Weekly magazine. I don't know the author or if his claims of being an "expert" are valid but it's info we need when we decide whether to run radial tires on original rims or not. He starts out by referring to a letter publised earlier.
"Bob Brooks' letter citing Sears selling radial tires raises deadly issues. As an accident investigator and an expert court winess on this issue, I remain extrememly concerned that the right information is getting to hobbyists. Rims for bias-ply tires, radial tires and disc brakes are made out of different alloys. Rims for bias-ply tires cannot use radials, and bias- and simply radial-ply rims cannot be used for disc brakes. The forces exerted by bial-ply versus radial-ply (as well disc brakes) are different and need rims made for them. Otherwise, there is over-flexing leading to rim metal fatique and breakage (commonly rim bead edge separation) with deadly results. The rim separations generally give no warning and are almost always catastrophic at speed. One can tell bias-ply, radial-ply and disc brake rims by their marking. An easier way is to make sure the rims come from a car year (1965 and newer) where radial tires were stardard or optional equipment. Disc brake-rated rims can run any tire. Many will disagree, touting their successful usage, some even offering advice with little knowledge of physics and metal fatique. But as a fatal accident investigator and veteran of 62 court cases on this issue, I'm warning everybody: Old bias-ply rims simply cannot continue to take radial tire sidewall forces. The Coker Tire Co. vintage tire catalog commendably gives much the same warning. There is help for Mr. Brooks and everyone else wanting to use radil tires on pre-1965 cars. The Hollander and Mitchell interchange manuals, used by practically every salvage yard, show rims with the same bolt pattern. Just check to make sure everything clears or check out any hot rod magazine for modern, safe rims. If you cannot find the right rims, please continue to use bias-ply tires."
Sam Egan, via e-mail
