I recently snapped the top off of one of my Presta valves, and saw it as an opportunity to learn how to change an inner tube, which I have never done before. I watched YouTube videos on it (I particularly liked the video from Trek) and felt fairly well-prepared. I bought some new tubes, some plastic tire levers, and off I went.

The Trek video shows how to do it with taking the tire only halfway off of the rim, but I followed a guide that suggested taking the entire tire off. I inflated and then deflated the inner tube, and loosely lined it around the rim (which most guides don't suggest...). I then stuffed the tube into the tire as I worked my way around, getting the tire beads back into the rim. As suggested in the Trek video, the final segment was difficult and required the most force, but I did it. I inflated the tire, and everything looked pretty good, except... there was one area where the tire didn't seem to be as tucked in to the rim as the rest. I prodded at it, deflated the tube and prodded some more, but I couldn't get it to look like everything else. I couldn't see any traces of the inner tube, though, and figured that the true test would be with a ride.

Everything was fine, initially. I was watching the tire carefully and paying close attention to the ride, and everything seemed to be as usual. But then it seemed like there was some asymmetry - hard to tell, though, since I had gone through a damp patch and only part of the tire was wet. Quality of the ride was unchanged. I kept going for a while farther, hit a few bumps, and just when I was thinking that I'd better dismount to really make sure that there was no asymmetry... *POP*

Trying to keep a good attitude, I figure that this is a chance for me to learn from my mistake and simultaneously practice patching an inner tube, which I have also never done before. The hole was easily found, right near the stem, where the tire had appeared suspicious to me. I patch the tube but am not totally confident in it, so I get out a fresh tube and go through the process again. This time I try it with the tire only halfway off of the rim, as they did it in the Trek video. Same issue, though - I just can't get the part of the tire near the stem to look like the rest of the wheel. I pushed and pulled at the valve, but on one side of the tire some of the inner tube remained, blocking it from going down as far as the rest. Worse yet, I discover that the tiny pump I had with me is broken, so I can't even inflate it. I wasn't too far from home, so I walked it back with the flat front tire.

Back at home, I take off the entire tire, line it with the inner tube, ever so slightly inflate the inner tube (as suggested in a wikihow guide), and then go through the process of putting it back on the rim, starting with inserting the stem first. It was even worse then, though, as the tire seemed to want to stay on the outside of the rims, and wouldn't go back inside. I deflated the inner tube and had the same problem.

It was then that I noticed a small tear in the tire - nothing that went all the way through, but a bit of the outside was revealing the material underneath. It was at that point that I figured I'd best stop mucking around, as I wasn't sure if the tear had always been there or if it was my doing. I had been intending to take my bike in for a tune-up, anyway; the wheel issue could be added to it. Feeling dejected and pathetic, I dropped my bike off and was told that there's a turn-around time of two weeks.

It's clear what happened the first time around: part of the inner tube got pinched by the tire, leading to the blow-out. Why was it so difficult to get the tire on properly near the stem, though? For reference, my wheels are 700x32, the tire is Nashbar Gridlock, rims are Alex R500, and the inner tubes are meant to fit tires 700x28-32 in size. It looks pretty easy in the YouTube videos, so why was I struggling?

Advice and kind words appreciated. I thought that this was supposed to be one of the most basic skills that cyclists should know; I'm not feeling too great about having to ultimately defer to a shop to handle it.