1 pointThey are a nice chunky looking tyre. Standard fitment on many Jeeps and were the size LR used for some models in the US, as 16" off road tyres are (or were) quite rare over there. They will be a similar width to a 265, but maybe a little wider in practice. Height wise, most 31.10.50's will normally come in at 29-30" against the tape measure. For example a BFG AT 31.10.50R15 is 30.5" tall. While a 265/75R16 in the same tread is 31.6" tall.
1 pointThere are various calculators on the web that will give you the metric size but I think you're roughly right. However, the height of these always looked a little small to me. I have some of these in the shed that I took off an old 110 I used to own and then I put them on my old 90. But they always looked a little too small to me, especially on the 110.