heaven on wheels

My bike's rolling again after about a month of exchanging grease for dust in the extra bedroom. I hadn't checked the bottom bracket for a while, and suddenly it was creaky and wobbly. Busy and lazy as I am, I tried to take it to the bike shop to get it fixed, but the bike guy told me to do it myself (you have to know this bike guy for that to make sense).

The reason I didn't ride my bike for such a long time is that it's unlucky. Right before I started having these problems, somebody kicked and bent my back tire. As soon as that was fixed I noticed the bottom bracket problem. I wanted to buy a sealed bottom bracket to replace it, but even that took three trips to the bike shop. It went like this:

"I want a sealed bottom bracket."
"Do you know what size you need? Bring in the old part so we can tell."
"I know what kind of bike I have. Does that help?"
"No."

(later)

"I want a sealed bottom bracket. Here's the old one."
"Do you know what size you need?"
"Uh... last time I was here, you asked to see the old part so you could tell what size I need."
"No, we actually have to measure the shell on your frame."
"I know what kind of bike I have. Does that help?"
"Oh, ok. It's probably this one."

(later)

I'm at home putting my bike back together, and (oh no!) the new part doesn't fit. Thing is, there's two sizes of these, a big size and a smaller size. They are supposed to have sold me the smaller size, yet this one is too big. What's going on? I measure my bike and it's 68 mm. I put the part together outside my bike and measure it; it's 73 mm, but it's marked 68. Huh? I look closer. The cartridge itself is marked 68 mm, but there's a collar that holds it still on the other end, and that's marked 73. Back to the bike shop. They are very speedy, for once, and immediately give me the right piece. Awesome! So today I get to bike to work.