What width rim do I need for my tyre?

This was a question from a YouTube viewer:

Well, a suitable rim width for a tyre isn’t an “opinion” thing. It’s a fact thing. Every tyre size has a minimum and maximum width which is dictated by the width of the tyre, and also the height of the sidewall. So, a 285/65/18 tyres may have rim widths of 8-10″, whereas a 285/75/16 may have rim widths of 7.5-9.0″, even if both are 285 width.

You should be able to find the permitted rim widths on the manufacturer’s website, as this example from Cooper Tyres shows:

Note that the rim diameter is fixed; a 285/70/17 can ONLY be fitted to a 17″ rim, not a 16, 17.5 or anything else.