Tire pressure when +2

[jaykay]

Off the top off my head there is Boyle’s gas law:

P1*V1=P2*V2 @constant temperature

You can see that it will give you a higher pressure if the volume is decreased. But is this really what correction pressure is necessary for your tire? I could not say myself.

You need: the volume of your present tire; recommended tire pressure; volume of your 19. You can then solve for the new pressure that will maintain the same pressure-volume system. It won’t be easy to accurately calculate/measure these volumes. Perhaps solid modelling might get you close.

Check the result against what would make sense, but whether this what your tire actually needs as a base pressure for tire load is another story.

A quality tire specialty shop should be able to give you the right guidance on this