Symptoms
- Tire feels squishy or fully flat
- Bike rides sluggish or wobbly at low speed
- Visible object stuck in the tread
- Slow leak that needs air added every few days
Likely causes
- CommonPuncture from glass, thorns, or debrisSharp objects penetrate the tire and tube, causing air loss.
- CommonPinch flat (snake bite)Hitting a curb or pothole with low tire pressure pinches the tube between the rim and the object.
- PossibleWorn or cracked tube from ageRubber degrades over time and can develop small leaks at the valve or seams.
- PossibleValve stem leakA loose or damaged valve core lets air escape slowly.
What to do
- Remove the wheel from the bike using the quick release or axle nuts.
- Use tire levers to pry one side of the tire off the rim.
- Pull out the inner tube and inspect it and the inside of the tire for the object that caused the puncture.
- Patch the tube with a patch kit or replace it with a new tube of the correct size.
- Partially inflate the new or patched tube and tuck it inside the tire before seating the tire bead back onto the rim.
- Inflate to the pressure listed on the tire sidewall and reinstall the wheel.
- Spin the wheel to check the tire seats evenly and isn't rubbing the frame.
Tools and parts
- Tire levers
- Pump or CO2 inflator
- Patch kit or spare tube
Bike inner tubeSearch: “bike inner tube correct size”
Tire patch kitSearch: “bicycle tire patch kit”
When to call a pro
Most bike shops can fix a flat quickly and cheaply if you don't want to do it yourself or don't have tools on hand.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.