Originally Posted by
prj71
According to me and where and how I'm riding. It's called "ideal" tire pressure and not "correct" tire pressure.
Ideal pressure is about finding a balance between reducing rolling resistance and increasing comfort. And that's different for everyone. Real world road conditions, make up of tire (higher or lower TPI), rider weight, normal riding position, tubed or tubeless etc. and not some silly mathematical formula or chart, will dictate what the tire pressure needs to be...And that is determined by experimentation.
The Zipp/SRAM guide doesn't claim to give you a "correct" pressure. It's a guide based on the relevant parameters and their experience. The variables you just listed are exactly those included in the calculator to give the user a more educated starting point, especially when moving to a different tyre or rim width.