I would strongly suspect that it was the wrong lock ring for the wheel. Back when we still changed tube required tires on a daily basis, we always checked to see that they fit right. I would suppose that there are very few tire guys left that know what they are supposed to look like. And those of us that are left are getting too frail to be changing tires. Something else we always looked for was the mark on the tire that is an indicator that the tire is seated properly.
Goodyear still has the same safety bulletin they had out in the 80's when we sold and ran Goodyear exclusively on our fleet. I think the bulletin is still very much on point.
http://www.goodyeartrucktires.com/pdf/resources/service-manual/Retread_S3_V.pdf
