How to Fix a Flat Bike Tire

Tools You Need

• Tire irons
• Screwdrivers (flat-head and Phillips)
• Wrench
• Patch kit, or new tube if patch kit fails
• Bike pump
• Ball-point pen or permanent marker
• Bucket of water (optional)

Step 1: Remove the Wheel

1. Remove the brake cable from the brake clamp by pulling the cable free. Some hand brakes have a lever you need to pull before the cable can be pulled free.
2. For a front tire, loosen the bolt that connects the wheel to the frame with your fingers, an Allen wrench, or a screwdriver (depending on your particular bike). If you have quick releases, unfasten the quick release.
    
   
    
   
3. Slip the wheel out of the fork.
4. For back tires, loosen the tire bolt or quick release. Drop the wheel out of the fork and move it forward, away from the rear derailleur. Slip the chain off the rear gear set to free the tire.
5. For bikes with coaster brakes, you can remove the front tire just by unbolting it. To remove the rear tire, you need to unbolt the coaster brake from the wheel. Use a small wrench and a screwdriver to disconnect the wheel from the coaster brake.

Step 2: Remove the Tube

1. Deflate the tube. For Schrader valves, remove the cap from the valve and press the metal shaft inside the valve down with your finger to deflate. Use the tip of a screwdriver if your finger won’t fit inside the valve. For Presta valves, press down the tip of the valve until the tube is deflated.
2. Slip a tire iron between the tire and rim at the point on the rim directly opposite where the valve joins the rim. This tire iron will serve as an anchor, so leave it in place once it’s under the tire’s edge.
3. Use a second tire iron to get under the tire’s edge near where you placed the first iron.
4. With the second tire iron, circle the perimeter of the rim to pry off the tire and free the tube housed inside.
    
   

Step 3: Check the Tire for Sharp Objects

1. Run your hand carefully along the inside and outside surface of the tire. Remove any objects that may have punctured the tube.
2. If you’re planning to use a new tube to fix the flat, skip to step 6.
3. If you’re planning to use a patch kit, proceed to step 4.

Step 4: Locate the Source of the Leak

1. Inflate the tube with your bike pump and look for a hole while listening for a hissing sound.
2. If you can’t find the hole, inflate the tube and place it in a bucket of water. Air will bubble from the hole.
3. Mark the hole with a pen, marker, or your finger.

Step 5: Sand and Patch the Tube

1. Open your patch kit. It should contain sandpaper, a small patch, and patch glue.
2. Dry off the area near the hole and sand it for about one minute. Sanding helps roughen the tube’s surface, which makes the patch glue bond better.
    
   
3. Dab the hole with glue and apply the patch to the hole.
    
   
    
   
4. Wait at least five minutes for the glue to dry before trying to inflate the tire.
5. Fill the tube with just enough air for the entire tire to take shape.

Step 6: Insert the Tube Back into the Tire

1. Insert the valve of the tube through the valve hole on the rim.
    
   
2. Tuck a portion of the tube inside the tire. Hold that portion inside the tire with one hand. With your free hand, continue tucking in the tube around the entire tire.
    
   

Step 7: Reattach the Tire to the Rim

1. Starting from the area around the valve, use both your hands to work the tire’s edges back onto the rim. Get as much of the tire onto the rim as possible. You’ll likely get almost all of the tire onto the rim and then be left with a stubborn, roughly 6" section that won’t seat properly along the rim.
2. Insert one tire iron just under the edge of the tire at a point where the tire fits snugly against the rim. Leave that tire iron in place (it’ll serve as an anchor point).
3. Starting from the other end of the stubborn tire section, use another tire iron to wedge the stubborn part of the tire back onto the rim. Move toward the anchor point you’ve created with the first tire iron until the entire tire is seated properly against the rim. Always work gently—the ends of the tire iron can puncture the tube.
    
   

Step 8: Inflate the Tire

1. Lean the bike against a wall or on its kickstand.
2. Use a pump to inflate the tire (see How to Check and Inflate Bike Tires). Check the tire pressure by pressing the tire’s sidewalls together every minute or so.
3. When the tire begins to feel hard, pump more slowly and keep an eye on the pump’s psi gauge.
4. Pump only until the gauge matches the pressure listed on your tire’s sidewall.
5. If your pump has no gauge, stop pumping once you can no longer squeeze the tire’s sidewalls in at all.

Step 9: Reattach the Brakes

1. For hand brakes, slip the brake cable back into the brake clamps. For coaster brakes, rebolt the brake onto the rear wheel.
2. Test the brakes before riding (see How to Maintain Bike Brakes).

Tubeless or Sew-Up Bicycle Tires

• Tubeless tires: Used mostly on mountain bikes. The tires are attached directly to the rim with no inner tube. A flat tire must be replaced with a new tire.
• Sew-up (tubular) tire: Used on competitive road bikes. The tire is sewn around the inner tube. A flat tire must be cut and resewn (consult a bike mechanic for help with this procedure).