[hankaye]

sdayman, Howdy;

Look at the differance in atmospheric pressure.......
Less external pressure would lead to more interior pressure.

Lots and lots of things effect the pressure in your tires.
Outside air temp., rian and other moisture on the road. elevation (both up and down), where ya live where ya go and how ya get there..... Road surface,
number of curves in a strech of road (moer in a short strech or less in a long strech), so on and so forth...
just thoughts (like peas), rattlin' 'round in the tin can of a skull I have...
The tire manufactures account for most of that when they design them, test'em so forth and so on some more......

hankaye