We know, from experience, that almost no one patches a tire tube anymore. Most cyclists just pack around an extra tube and discard the one with the hole. What happens, however, when you’re on a long cycling trek — check out our blog of our cycling trip from Victoria, British Columbia, to Portland, Oregon — and you keep riding over glass, metal, or even nails? You run out of new tubes, and you’ve got to patch. Here’s how you do it!

• 2 tire levers (3 levers make the job easier)

• Glue

• File (or sandpaper)

• Patch

• Watch

• Pump

1. Empty any air left in the tube by pressing on the tire valve.

2. Remove the wheel from the bicycle. Most bicycles these days have quick release levers (invented by Tullio Campagnolo). If not, then usually a crescent wrench will do the job. You might want to release your brakes before turning your bike upside-down to remove the tire.

3. Remove the tire using the plastic tire levers. The levers lift the tire off the rim. Take one lever and work it under the tire. Hook the end onto the spoke. Take the second lever and slide it under the tire to the left of the first lever, about 15 cm away. Hook that lever to a spoke. Take the first lever, and repeat the process, always going to the left. Eventually, you can slide one lever along the rim until the tire pops off.

4. Take the tube out — first checking to see if a nail, thorn, or glass is lodged in the tire — and pump it up. Listen for a leak. When you’ve found the leak, keep track of the hole; you can use a white grease pencil to mark it. (We didn’t have one, but it was really no problem.)

5. Empty the air from the tube again. Use the file and scrape the hole and surrounding area really well.

6. Apply the glue to the scraped area around the hole. Wait five minutes while the glue dries.

7. Place the patch — keep the plastic on, facing away from the tube — and hold it down really hard. You can stand on it. Wait at least a minute. Remove the clear plastic. If the patch comes off, try again. You might need to scrape the area harder, or wait longer for the glue to dry, or even press on the patch harder.

8. Inflate the tube again. Does air leak out? If not, let the air out of the tube, and start working backward, putting the tube in the tire, the tire on the rim, tightening the quick release bolts, and reconnecting the brake (that’s really important).

You’re fixing a flat tire. The tube is scraped to allow the glue to bond better. The patch is just a small piece of the same material as your tube.

The tire we used for this project had two patches on it that held for over a year. The tube was patched twice along Route 30, a highway that runs from Longview, Washington, to Portland, Oregon. A lot of debris littered the area close to the curb where we were riding. And by the way, the two patches were still holding, but we drove a nail through the tire for this project. The things we do in the name of science.