Back when I used to race (and I use that term loosely) my road bike I made it a rule to never do any maintenance on the bike the day before or the day of the race more involved than putting air in the tires. The reason being I always wanted time to do a shakeout ride before race day to make sure everything was working properly. The same rule applies when I go touring.
The chain on my bike was worn, so I replaced it. How do I know it was worn? Because a new chain has a pitch,or distance between links, of exactly 1/2 inch. A quick measurement showed how much my chain had “stretched”
Of course the chain doesn’t actually stretch, the material on the pins and on the links wears away resulting in a new pitch. Over time the teeth on the rear wheel cogs and on the front chainrings will wear to mesh with the new pitch. Then when a new chain is put on, one with a 1/2 inch pitch, it will not lay evenly on the teeth of those other drivetrain components and those will need to be replaced as well or the chain will jump and skip when pedaling. New chains are relatively cheap so I say when in doubt, whip it out.
I will carry a small chain tool with me as well. Chains seldom break, but if they do it could leave me stranded in the middle of nowhere. I will carry the cut off section of a few links from the new chain along with a spare quick link. I’m sure an internet search will reveal a number of videos on how to repair and replace a chain so I will not duplicate that here.
I decided to replace my rear tire as well and take the old one as a spare. The Panaracer T-Serv tire had over 2000 miles of multi surface riding on it and it still has some life in it. I just would rather start out with a fresh tire on this trip. I will be using the Schwalbe Marathon Supreme, my first experience with Schwalbe tires. I will report on that later.
I was a little surprised to see that the Schwalbe tire was a millimeter or so narrower than the Panaracer tires even though both tires are nominally 700 x 32.
I still need to change my front rack and install the headlights but that’s enough for today.