Yesterday night, I went out and bought a pair of brand new inner tubes from Walmart. I put in one of the inner tubes that same night, but put air in it this morning. My friend called and was on my way, road on it fine and everything (although for some reason something kept leading me to think the rear tire was flat). I get back from riding, I assume the tube is fine, about 10pm I go to take the bike out of my truck bed and find the rear tire is FULLY flat. It is a 20" Schwin Flacon that my older brother gave me just because.
... ... why is this happening? ... HOW is this happening? I filled up the inner tube around 9am, held air fine. got to my friends house and started riding about 12/1 I think, checked the rear tire and FULL of air, even put a tire gauge to it and it read to 40 psi (which is how much I put in when I filled it this morning), come home about 5/6 pm ... I am assuming the tire is still full of air at this point, 10pm go out to take out the bike from my truck and COMPLETELY flat.