I recently bought a decent stand pump with an attached guage so that I can make sure that my tires are properly inflated. The max pressure listed in my tire (700x28) is 85 psi. The other day, I made sure the air pressure on my rear tire was right around 85 psi and I went out for a 22-mile ride. The next day when I checked the pressure, the gauge showed that it was down almost 10-15 psi. I expected some loss, but is that much normal?
It's a new tube and tire and I've only gone for a couple 20-mile rides on it so far. This is also the first time that I've had a decent pump with a built-in gauge. Before this, I was using a little hand pump and just pinching the tire to see if it felt right...not good...I know.