Don’t rely on others. “People need to recognize that now there are different cassette sizes, so there are different chains depending on what gear you have. A lot of people are like, ‘Oh my friend is always prepared they always have the stuff, I’m not going to bring anything.’ All of the stuff now is very bike-specific, and you have to have your own package of stuff.”
It’s both surprising, and not, if you think about it. The way I’ve usually seen it happen is first the rear tire goes flat, then the front one. My theory is that both tires went through the same pile of glass/thorns/metal bits and they both picked up junk. the reason for the flat occurring on the back first is because there’s more weight on that tire, so the offending article works its way through the tread more quickly.
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.
This gentleman is a true professional!! He is an ex-Marine and I will tell you that he represents them well. He is honest, knowledgeable and extremely reasonable. He repaired my son's bike while I waited and went over the whole bike and made the required adjustments replaced an inner tube and all for 20 dollars!!All the kids in the area pass by and call him by his first name. I will recommend him to everyone I know since there are very little of them out there!!
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.