I figured I would post this in off topic since it's not really vehicle specific. Anyways, there have been plenty of threads on correct tire pressure and most people go based on the door placard even when running tires with a much different size and load index vs. stock. I am also reading that the correct way is to use a table like this: https://static1.1.sqspcdn.com/static/f/589830/23447320/1378330097907/Discount+Tire+inflation.pdf to match up higher load index tires with the correct PSI.
For example, the factory 18" Pirellis on my car had a load index of 92 or 1389lbs per tire. This seems fairly common. I run 245/45/19 on the front and 275/40/19 in the rear, been doing it for years, since almost right after I bought my car since I swapped out the wheels/tires right away. I run 35psi front and 30psi rear and have had no weird wear issues. I always buy summer Y rated tires and they always seem to have a load rating of 102 front 105 rear.
HOWEVER, when consulting the chart and matching it up to roughly the same supported weight per tire which is apparently the correct way to do it, I come up with crazy low "correct" tire pressures of 25psi front and like 23psi (or even 22) rear. How is this possible? There is no way that can be the correct tire pressure. Or maybe it is, the tables are gospel, and we have all been running way too high of a tire pressure and these low pressures are some kind of holy grail for ride and handling?
For example, the factory 18" Pirellis on my car had a load index of 92 or 1389lbs per tire. This seems fairly common. I run 245/45/19 on the front and 275/40/19 in the rear, been doing it for years, since almost right after I bought my car since I swapped out the wheels/tires right away. I run 35psi front and 30psi rear and have had no weird wear issues. I always buy summer Y rated tires and they always seem to have a load rating of 102 front 105 rear.
HOWEVER, when consulting the chart and matching it up to roughly the same supported weight per tire which is apparently the correct way to do it, I come up with crazy low "correct" tire pressures of 25psi front and like 23psi (or even 22) rear. How is this possible? There is no way that can be the correct tire pressure. Or maybe it is, the tables are gospel, and we have all been running way too high of a tire pressure and these low pressures are some kind of holy grail for ride and handling?
