I visited my favorite bicycle shop, I. Martin Cycles, on Friday to pick up a new spare tube. On Thursday I did a routine air pump on the tires and discovered that that back tire was really low. Like, unusually low. So I pumped it up, went to work, and I noticed after work that the pressure was already going down significantly again. In fact, I was concerned I might not make it home without a flat. However, I did make it home and decided that I would change out the tube and check the tire for debris.
One of the first things they teach you about changing a tube is that you don't need to remove the tire from the wheel, but in this case I removed everything so that I could feel around the inside of the tire and inspect it for anything sharp. It turned out to be perfectly fine. I couldn't find the problem with the tube either. I was thinking maybe the valve stem was tearing, but I couldn't find that problem, although I am now suspecting maybe the valve had a slow leak. Regardless of the true problem, I had no choice but to change it out, which I did, and then I went to get a new spare. The new tube was $5.99.
While I was in there, one of the bosses came up to me and thanked me for the nice tweet I'd made about their store, and I took a moment to talk about my desire to go cross-country, the need for a new bike because my handlebars had one position only. he show me some new grips that had an extension on them that allowed for a 2nd hand position. That's definitely a possibility I'll consider for this bike.
I also asked about mirrors, and he said there were two options: helmet mirror or left grip mirror. I didn't purchase either, since I'm on a tight budget at the moment, but the helmet mirror sounds great although I'd wait on that until I get a new helmet this year. I still might get a grip mirror.
The tube is now staying inflated, but I still have no idea what was wrong with the other one. The point is, if there is anything wrong, just replace it. They're cheap enough, and it's not worth the misery of having to fix it on the road.