Just so it's clear (it took me a while to fully understand). The metric tire sizes that look like this: 235/75r16, give first the tread width in mm (235mm) followed by the sidewall height as a percentage of the tread width (75% of 235=176.25mm) then followed by the rim size in inches (15 inches). To calculate how tall they are, you need to convert the sidewall height to inches (25.4mm/inch so 176.25mm=6.94inches) then multiply this by two and add in the height of the rim to get the total tire size (6.94inches x 2)+16inches =29.88'' tall. So a 235/75r16 tire would be roughly equivalent to a tire that is 29.9 inches tall with a tread width of 9.25 inches.