A flat tire is never welcome, but for individuals out on long rides on country roads, they can be a serious problem. Many road cyclists prepare for this by carrying tools on their rides that can help seal a puncture in a tire and allow them to ride home. But not all blowouts are fixable, and if you are in a rural area, it can be very difficult finding a way home. For this reason, it's important to understand how flat tires occur and what you can do to prevent them.
Punctures are the most common way tires go flat, and they come in two forms: debris punctures and rim punctures. Debris like glass, nails and even sharp rock shards can penetrate the thick tire and puncture the tire tube. Debris punctures are probably the hardest tube damage to avoid because the debris can appear anywhere when riding, and it can be difficult to spot on the ground. Rim punctures can occur when a sharp edge or burr in the rim's metal catches the tire tube and creates a puncture. This can occur if the rim is of poor quality, or if the tube has been installed properly.
Some tire tubes become ruptured through what is called a "snake bite" puncture. This occurs when a tire's tube is low on air and is impacted by a pothole or other blunt force on the rim. The pressure forces the rim to move, encroaching on the space around the tire and pinching a small part of the tire, puncturing it. This is much less likely to happen if your tire is properly aired. You tire may also incur damage through the sidewall if it absorbs damage on its least-protected area. And some poor installation jobs can cause a tire to blow completely due to the tire coming off the bead.
Reduce the occurrence of debris punctures by routinely checking your tires for debris and removing any stuck shards; many times a piece of debris will not immediately break through the entire tire and puncture the tube. You can also apply a tire liner or use a puncture-resistant tire to further reduce the risk of punctures. Rims should also be looked over prior to installation of a tube; a deburring stone can easily remove any sharp points. Although some people recommend using talcum powder on a tire to make the installation of the tube easier, PerformanceBike.com discourages that because it can increase the risk of blowouts. Tire pressure should also be checked regularly to keep the tube filled and prevent snake bite punctures.
Awareness when riding your bike is important. By looking ahead at the upcoming road, you may be able to identify shards of glass or other debris and steer clear of potentially hazardous elements. This isn't a fail-safe approach, but hazards are a part of riding your bike. Your best approach is to be aware of the risks and to prepare yourself for the worst by having repair tools on hand.