[Mike C]

285 would be fine. It is a narrower rim than recommended for that width, but so it is for your 265 as well.

I have a set of 36 12.5 16.5 Wrangler RTII (bias humvee tire) mounted on a set of 16.5" dually rims that I am going to fit on my K30. That's a 315 section width compareable tire. I had a set of 2 1/2" spacers made up for the rear to fit between the inner and outer wheels. They were made to order and they listed 2" or 3" and I wasn't sure what to get and asked about the 2 1/2". No additional charge for the custom width but I don't remember who made them now. It was harder to find the older truck setup than a newer one.

The tire guy said he thought was too narrow and when I picked them up he was surprised about how well they fit. But an independent place. The chains may not mount that up for you.