It looks like bearings have pull dates no longer than five years out. Some are two or three. Another thing I didn't know is that SKF is one of the oldest bearing manufacturers and is located in Sweden with factories all over the world. There's a date code on the box which is three numbers followed by a letter. The numbers are the day of the year and the letter signifies the year. A is something like 2001 and progresses through the alphabet, then starts over.
The G5 wire wheels were pretty easy - just apply propane heat to the bearing carrier so the bearing can just drop out when hot enough. The new one pretty much drops in. Doing this on the side of the road would require something to remove that giant snap ring, and a way to heat the carrier. I doubt a little butane torch would do it. For cast wheels, that's another matter and I haven't dealt with them. I suspect a blind bearing puller is necessary.
