Wierdness. I had my FIRST flat today, can you believe that crap? Finally, I'm no longer a virgin- it took three years. I just changed tires (Panaracers) and I was using every word in my vocabulary as I was about ten miles from home in sweltering heat with no shade in site. So I take a scene from Christmas Story and time myself on my chrono to see how long it takes to change the tire..lets just say I really really suck. It was like 20 minutes

Anywho...no punctures, no tears, no debris, took the tube out, no holes, the tires AND tube are NEW, about 30 miles on them. SO I decide that since I can find NO leakage or hole, I just put it back on and figured I'd learn from the experience. About two miles later I'm very flat and now since I'm not too far I thought I'd just inflate it every two miles or so (I know, dumb but it was 14,567,899,944 degrees out). So I take out my CO2 thingy and pump her up, and away I ride and she's still hard as a rock as I type this 8 hours later. It's not leaking, what gives? And yes, the little screw down thingy on the Presta was tight. I'm perplexed.

No idea, but for peace of mind I would change out that tube anyway.

Agreed, because Murphy's law says next time will be 6 miles from civilization with a dead cell battery and you forgot the stuff to fix it.

Be happy you didn't do the stupid thing I did on my first flat. Removed the tube...put in the "new" tube, replaced the rear tire and used the only gas inflator I had to inflate the tire.....only problem was I put the original tube in the tire and not the new tube.

Oh man I was like fondling that CO2 cartridge, the only one I had. I do plan on changing the tube and getting more CO2 cartridges before I ride Saturday. I can't see hand pumping for a bajillion hours, but I do carry one just in case.

The puncture is there, no doubt about it. Maybe you covered it just right when you reinstalled the tube, preventing it from leaking. Blow the tube up and stick it under water. You'll find it. And always carry two Co2 carts.

there is a leak/puncture for sure, change the tube.

Same here, I've never had a flat due to an impact of some sort, but my tube developed a hole and the tube was deflating deliberately.

Put it under water and move the valve side to side.

Tubes are $5. I would have thrown that one as far into the ditch as possible from the start (just kidding - it would have gone into my jersey pocket).

Most of my flats in the last few years seem to be around the valve stem. I bet there is a small hole there somewhere.

Maybe there was some crud down in the valve that got blown out of the way the last time you inflated it.

...and there will likely be zombies. Yes, replace the tube and be thankful for the practice.

+1 to the tiny hole near the valve stem somewheres... It will seem to be fine but will eventually go flat again.

Had a similar problem last week. I was reading a thread about co2, looked over at my bike and noticed a flat. I patched the tube and did 2 rides for 75 miles with no problems. On Saturday, I was 4 miles into a century and the tire was soft. Pulled out the tube and couldn't find a leak so I pumped it up and finished the ride. The next morning it was flat. I just figured that Jesus loved me.

Yup, that little puncture is still there somewhere - change it out while you are at home in a comfortable air-conditioned area. Look for the puncture at leisure, and if you truly cant find the hole, throw the tube in the bin anyway, 'cuz it will otherwise reveal itself at the most inopportune time!