flat tire

Yesterday I took a roughly 240 mile round trip to cedar point, ohio with a friend. before I left I did all the usual stuff (check fluids, tires, cleaning, etc.) for a while I have noticed my front driver's side tire looks low, but isn't. all my tires were around 30 psi and i put them up to 33. I drove back and everything was fine. This morning a spot opened up on the street closer to my house so I moved my car. Less than an hour later, my friend stops by because he left something in my car. I go outside to my car and realise that the front driver's side tire is flat. :banghead: I angrily take off the wheel and quickly visually scan it, and don't see anything that looks deep enough to make the tire go flat that quickly. So I grab a spray bottle with soapy water and fill the tire with air and soap test the whole tire, romving small rocks and one piece of glass from the treads. Nothing bubbles up, but the tire is still losing air very slowly. Check the valve stem and its tight. But then I decide to check the actual rubber valve piece and its definately leaking. If I bend it at all it leaks even more. The only part I don't understand is how it suddenly lost a bunch of air when it appears to have been leaking all along, and if it wasn't leaking all along, what caused it to start leaking. Anyone have any ideas?

make sure its the right tire because the wrong tire mounted on a rim wont seal properly and slowly leak do to the inside walls of the tire not expanding to seal off to the rim so spray the soapy water around the rim on both sides to see if it leaks there

no, I'm sure it's the right size tire, all the tires are the same size.

you filling it with air that morning probably tweaked it a bit and tore into it.

you filling it with air that morning probably tweaked it a bit and tore into it.
I thought of that, but I filled it two days before it went flat and drove it about 300 miles. It was fine an hour before I saw it flat.

the stem may have clipped something

the stem may have clipped something
Nope, the valve stem was on the front driver's side and I moved up the street along the curb (50 feet) on the passenger's side. Something could have clipped the valve stem though, but not the valve stem hitting anything. I still couldn't imagine anything would get that close to the valve stem without scraping my car or something...

a rock right before you got home?

just take it to a tire place and have them look at them maybe rebalance them replace the stems and put more of that sticky crap they put on there. id say 20 bucks as long as you dont have to get new tires