Hi Dave
https://www2.pajeroclub.com.au/forum...ead.php?t=1657
The tyre calculator you have listed doesn't seem to work as I think it's expecting a UK postcode. I use this one all the time. great to compare everything about your original tyre size to a new one and it's in metric! It tells you how your speedo will change, etc.
https://tiresize.com/tyre-size-calculator/