2500HD E-rated tire pressure question

[jocko]

Does anyone know why GM lists 60 psi front and 80 psi rear for E load rating tires on a 2001 2500HD? i.e. why the split? Tires get rotated (as in, rotated front to back, crossed, etc at mileage intervals, etc) so that implies deflating and inflating as tires move around to keep the tire pressures correct.

Have seen a few threads on here discussing proper inflation pressure for E load rating tires - folks seem to want to under-inflate them. As far as the door markings for pressure, it's the 60/80 split mentioned above. The tires just display 80 psi at max load (which, on non-E-rated tires usually meant something less than that number was normal - but from all I can tell/read/pick out of the manuals, 60 front/80 rear seems to be the actual required inflation at all times, loaded or unloaded). (These particular tires are LT24575R16, the original factory tires on the truck from 2001). But asking in more of a general nature, not specifically about these particular E load rating tires, more like any E tires.

Thanks all.