[Norm Peterson]

Keep in mind that the dimensions provided by the tire mfrs or Tire Rack apply only to tires mounted on wheels of "measuring width".

For every half inch wider rim width, the section width of the tire will increase by approximately 0.2" (5 mm). Meaning that even though the amount of 'sidewall bulge' is smaller, the actual width sidewall to sidewall has increased.

This gets more important when you're venturing off into uncharted territory with tire and wheel widths. Where the difference between 'make' and 'break' for clearance concerns can be smaller than 2 mm. Been there, with even less final clearance than that. Had to make my own 0.025" thick spacer once (not a typo with an extra zero).


Norm