What are the common causes of bicycle punctures, and how can they be quickly repaired?

Speaking of flat tires, it's truly an annoying problem every cyclist encounters. But don't worry, it's not difficult to handle.

Common Causes of Flat Tires

Basically, there are a few main scenarios:

Puncture (Most Common): This is the most direct cause. On the road, there are always bits of glass, small nails, sharp stones, or tough plant thorns. If you accidentally ride over one, with a 'hiss,' your inner tube gets punctured.
Pinch Flat (Snakebite): The name is quite descriptive. This usually happens when your tire pressure is low. If you ride over an obstacle like a curb or a deep pothole a bit too fast, the rim and the ground momentarily pinch the inner and outer tires together, creating two closely spaced holes in the inner tube, just like a snakebite.
Valve Leak: The valve is also a weak point. Sometimes the base of the valve ages and cracks, or the valve core inside becomes loose or damaged, causing air to slowly leak out.
Rim Interior Issues (More Hidden): The rim has a protective rim tape that separates the inner tube from the sharp ends of the spoke nipples. If this rim tape ages, breaks, or shifts out of place, the sharp spoke nipples can chafe and puncture the inner tube. This type of leak is usually slow and harder to detect.
Tire and Tube Aging: All rubber products have a lifespan. After prolonged use, the outer tire's tread wears down, reducing its puncture resistance; the inner tube's rubber becomes brittle, and it might crack and leak on its own.

How to Quickly Fix a Flat

For a quick roadside fix, the most recommended method isn't patching the tire, but rather directly replacing it with a spare inner tube. This is much faster than fumbling in the dark to find the hole and waiting for glue to dry.

Tools you'll need:

Tire levers (at least two)
A spare inner tube
A portable pump
(If choosing to patch) A patch kit, which includes a scuffer, glue, and patches

Quick Tire Change Steps:

Remove the wheel: First, take the wheel off your bike. If it's a quick-release skewer, just open the lever; if it's bolted, you'll need a wrench. Remember to loosen the brakes so the wheel comes off more easily.
Release remaining air: Press the valve stem to let all the remaining air out of the inner tube.
Pry off the tire: Insert a tire lever into the gap between the outer tire and the rim. Gently pry it up to lift one side of the tire bead out of the rim. Hook this lever onto a nearby spoke to hold it in place. A few centimeters away, use another tire lever to pry open the tire in the same way, then slide it around the rim until one side of the outer tire is completely off.
Remove the inner tube: Pull the old inner tube out from between the outer tire and the rim.
【CRUCIAL STEP】Check for the culprit: Before installing a new tube, you MUST inspect thoroughly!
- Carefully run your finger along the inside of the outer tire to check for any sharp objects embedded in it. If you find one, remove it. Otherwise, the new tube will immediately flat again.
- While you're at it, also check if the rim tape inside the rim is intact and hasn't shifted.
Insert the new inner tube: Inflate the new inner tube slightly so it has some shape. This makes it easier to insert without twisting or getting pinched. First, insert the valve into the valve hole on the rim, then evenly tuck the inner tube inside the outer tire.
Reinstall the outer tire: Starting from the opposite side of the valve, use both thumbs to gradually push the edge of the outer tire back into the rim. The last section will be tighter; use the palm of your hand to push it in. Try to avoid using tire levers here, as it's very easy to pinch and puncture the new inner tube!
Inflate the tire: Once installed, inflate it a little first, then check if both edges of the outer tire are evenly seated in the rim. Once confirmed, inflate to the appropriate tire pressure (the recommended pressure range is usually marked on the outer tire).
Reinstall the wheel: Put the wheel back on the bike, tighten the quick-release or bolts, and re-secure the brakes. Spin the wheel to ensure everything runs smoothly.

Done! Once you're skilled, the whole process only takes about 10-15 minutes. Practice a couple of times, and you won't panic at all the next time you get a flat.