Getting a flat tire can really suck, but it can also be a great learning experience. Just as safety technicians examine airplane crashes to learn what went wrong and prevent it from happening again, you can do the same thing with the flat tires on your bike (ya, it’s a bit of a stretch to relate flat tires to crashed airplanes, but you know what I’m getting at…). Don’t let your trip be delayed by constant flat tires, analyze why they went flat and learn how to fix it from happening again. There are 4 general types of flat tires and they can all tell you something useful:
This is the most common type of flat for most people. It occurs when a rock, nail, piece of glass, or other sharp item penetrates through your tire and creates a small hole in the tube. Puncture flats will usually let air out of your tire somewhat slowly, and it may take upwards of a couple miles before your tire runs completely flat. When you get a puncture flat, it is important to check your tire to make sure that there are no sharp objects still lodged in your tire. Luckily, a puncture flat is usually easy to patch. If you find yourself getting several of these types of flats, it may be an indication that you are traveling over terrain which is too rough for your tires. If this becomes problematic, you may want to invest in a tire liner ($5-$10) which goes between the tube and the tire and can provide extra protection.
A blow out occurs when a large hole is formed in your tube, causing it to let out all of the air instantly and pop. The vast majority of blow outs are caused when the tire cannot adequately hold the tube inside (i.e. the tire gets torn). Blow outs can also happen on occasion if there is a problem with the stem of the tube (the stem is the metallic part where you pump it). Blow outs are usually caused by either a dangerously old tire or by hitting something pretty big and nasty. Blow outs tend to make fairly large holes in tubes which are very difficult if not impossible to patch. The best ways to avoid blow outs is to make sure your tube and tire are properly installed and that you replace your tires before the tread gets dangerously low.
Pinch flats are caused by your tube being compressed (pinched) between the ground and the rim of the wheel. This type of flat commonly happens when your ride over a large crack or a pothole. It is easy to identify a pinch flat because it will leave two small holes which look like a snake bite. You may find yourself getting an excessive amount of pinch flats if you are carrying too much weight or if your tires are not pumped to a high enough PSI. These flats can also be caused if your tires are too skinny relative to the width of your rim. Sometimes you can patch a pinch flat, but it can oftentimes be hard because you need to patch two holes instead of one.
Sometimes something happens to your tube which causes it to slowly lose air over the course of a day or two (or maybe even longer). It’s important to remember that no tube is 100% airtight, and even a perfectly good tube will go flat after several months if you do not pump it up. Slow leaks could be caused by a microscopic puncture, or even simply by a defective tube. It is often impossible to physically see the hole which is causing a slow leak, but you should be able to find it and patch it if you submerge the tube in water.