Originally Posted by
patentcad
Duh.
120 lbs psi when I left. 60 lbs when I got back. But if it will hold 60lbs that means it probably doesn't have a puncture. I think it's a flakey presta valve. I pumped it up earlier, let's see if it holds 100+ lbs sitting in the garage for 12-24 hours.
You can get tiny leaks in the tube that will give that same symptom. Though if you continue to pump up and ride, it will start leaking faster after not too long.
Either way, you need need a new tube. Pumping up a tire that let a bunch of air out without performing any type of repair is futile.