I think i know what’s happening with my bike.

For the past few weeks (weeks!), I’ve been having an endless shitload of trouble getting around on the bike, especially when it’s cold. Recall my post from December, wherein I observed:

What happens is I’ll be pedaling along, hit the shift lever, and immediately my pedaling loses all resistance. I don’t know if that makes any sense. It feels like instead of pushing against something when I pedal I’m spinning in thin air, like there’s no chain attached to the pedals.

Well, it’s not just happening while shifting any more… it’s happening while just pedaling down the road. A lot. Especially when it’s cold. It has caused much cursing in the last couple of weeks.

After doing some Googling, going over to Sheldon Brown’s site, and inspecting my chain, I’ve pieced together what’s happening. I think.

Sheldon Brown gives a technique for measuring chain and sprocket wear:

The normal technique is to measure a one-foot length, placing an inch mark of the ruler exactly in the middle of one rivet, then looking at the corresponding rivet 12 complete links away. On a new, unworn chain, this rivet will also line up exactly with an inch mark. With a worn chain, the rivet will be past the inch mark.

Sheldon says when you measure the chain and count links, there should be less than 1/16″ difference between the end of your ruler and the rivet of the 12th link you’re measuring. More than 1/8″ difference is bad and indicates that your chain and sprockets are worn beyond repair.

I have 1/4″ difference.

So, clearly, my chain and sprockets are worn out and need replacing. The chain slips the most when it’s cold. I think this is because the components are *so* worn out that the metal contracts just enough in the cold that the chain can’t grab the sprocket teeth on the back cassette, and therefore the crank spins freely. This is not very useful when, say, you’re crossing an intersection while a car waits behind you to turn right. Oy. At least I know what’s wrong with the thing and I can do something about it now.

So I need to get down to Derailer and see if I can con someone into helping me replace the damn chain and cassette. It may be worth looking into how much new components would be, actually, but I really don’t want to spend the money. So far this bike has cost me $10 for a basic set of lights. I like that and I’d like to keep it that way as long as possible.