How to fix a bike flat
To fix a bike flat, take the wheel off, let out any remaining air, lever one side of the tire off the rim with plastic tire levers, and pull out the tube. Find the hole, then run your fingers carefully around the inside of the tire to remove the thorn or glass that caused it. Patch the tube or fit a new one, reseat the tire and pump it up.
About 25 minutes to learnEveryday skill
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How to do it
- Shift to the smallest rear cog if the flat is at the back, open the brake release if there is one, and remove the wheel.
- Let out all the air, then hook two tire levers under the tire bead a few inches apart and pull one side over the rim.
- Pull the tube out, leaving the valve until last.
- Pump a little air into the tube and listen or feel for the leak, or dip it in water and watch for bubbles.
- Run your fingers slowly around the inside of the tire and check the rim tape to find what caused the flat.
- Patch the hole following the kit's directions, or use a new tube of the size printed on the tire's sidewall.
- Put a little air in the tube so it holds its shape, push the valve through the rim, and tuck the tube inside the tire.
- Push the tire bead back onto the rim with your thumbs, check no tube is pinched, inflate to the pressure on the sidewall, and refit the wheel.
Common mistakes
- Fitting a new tube without finding the thorn, which punctures it again at once.
- Using a screwdriver as a tire lever and pinching a new hole.
- Pinching the tube between tire and rim while reseating.
- Forgetting to close the brake release before riding.
Quick self-check
Three questions. Your last score is kept in this browser.
Teach this to someone
A one-page sheet for showing a friend, a roommate or a kid: what to say, what to show, and one question to check it landed.
Teach: How to fix a bike flat
What to say
To fix a bike flat, take the wheel off, let out any remaining air, lever one side of the tire off the rim with plastic tire levers, and pull out the tube. Find the hole, then run your fingers carefully around the inside of the tire to remove the thorn or glass that caused it. Patch the tube or fit a new one, reseat the tire and pump it up.
What to show, in order
- Shift to the smallest rear cog if the flat is at the back, open the brake release if there is one, and remove the wheel.
- Let out all the air, then hook two tire levers under the tire bead a few inches apart and pull one side over the rim.
- Pull the tube out, leaving the valve until last.
- Pump a little air into the tube and listen or feel for the leak, or dip it in water and watch for bubbles.
- Run your fingers slowly around the inside of the tire and check the rim tape to find what caused the flat.
- Patch the hole following the kit's directions, or use a new tube of the size printed on the tire's sidewall.
- Put a little air in the tube so it holds its shape, push the valve through the rim, and tuck the tube inside the tire.
- Push the tire bead back onto the rim with your thumbs, check no tube is pinched, inflate to the pressure on the sidewall, and refit the wheel.
The check question
Ask: What must you do before fitting the new tube?
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- How to teach a kid to ride a bike
- What to keep in your car emergency kit
- Every skill in Yard, Garage and Seasons
Last reviewed . First published .