In addition to the Rema patches, put a new tire tube in your kit. The best method for dealing with a flat roadside is to swap out the tube and save the task of patching for later. If you’re not sure what size your tires are, it’s printed on the sidewall of the tire. This inner-tube buying guide has some photos of where to look. What brand is almost irrelevant as many tubes get manufactured in the same place, so whatever your local shop has behind the counter for under $10 will work fine. The only reason to spend more would be to save weight.
Based on what we found, we chose the most relevant items and used them all. To test patches, I repaired holes using four different types of patches, from Novara (REI’s now-discontinued house brand), Park Tool, and Rema. Patching a tube isn’t hard but there are a few tricks, and the key was attention to detail and patience. I was extremely diligent in following proper patch procedure, which includes a thorough sanding of the entire area to be patched (for max stickiness) and properly letting the vulcanizer dry on both surfaces before applying. For the peel-and-stick patches, I went so far as to prep the area with canned air to ensure as tight a seal as we could possibly muster.
There are patches that don’t require vulcanizer—the infamous peel-and-stick. One brand, the Park Tool GP-2, has some genuinely enthusiastic endorsements, so we tested it. I applied Park Tool patches to four different tires, at three different psi levels (60, 90, and 120). Three of the four didn’t hold—two released within minutes. The fourth deflated overnight. I redid the test, but repeated a second time, they all leaked within a day.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.