In regards to tire psi and gauges I quit using them I found it was easier to use my hand pump then sit on the bike lightly bouncing my weight up and down and watching how much the tires buldge. If it looks like to much I add more and I find it better to set it higher like that especially if youre riding the road but the way the tire looks with your weight on it is key to ensure you’re not running too high or too low. After increasing tire pressure using a gauge I still got flats and some tires are softer than others that’s why I don’t use a gauge anymore