Symptoms
- Tire loses air quickly after inflating
- Hissing sound from the sidewall or tread while riding
- Sealant visible weeping through the tire casing
- Tire won't pop onto the rim bead evenly
Likely causes
- CommonInsufficient or dried-out sealantTubeless sealant dries out over months and needs periodic refreshing to seal small leaks.
- CommonTire bead not fully seated on the rimAn unevenly seated bead leaves gaps that leak air.
- PossiblePuncture larger than sealant can handleBigger cuts or gashes need a tubeless plug in addition to sealant.
- PossibleDamaged or incompatible rim tapeTubeless setups need airtight rim tape rated for the rim's spoke holes.
What to do
- Check the sealant level by removing the valve core and looking inside, or feel for sloshing when shaking the wheel.
- Add fresh sealant through the valve stem (with the core removed) if it's low or has dried into small dried chunks.
- Inflate the tire with a high-volume pump or CO2 to help pop the bead into place, listening and looking for it seating evenly around the rim.
- Rotate the wheel to distribute sealant across the tire interior, which helps it find and plug small leaks.
- For a visible puncture, insert a tubeless plug using a plug kit before adding more sealant.
- Check the rim tape for gaps or damage if leaks seem to come from spoke hole areas rather than the tread.
- If the tire won't seal after fresh sealant, proper bead seating, and a plug attempt, a bike shop can assess rim tape or a larger tire defect.
Tools and parts
- Tubeless sealant
- High-volume pump or CO2 inflator
- Tubeless plug kit
Tubeless sealantSearch: “bicycle tubeless tire sealant”
Tubeless rim tapeSearch: “bicycle tubeless rim tape”
When to call a pro
A bike shop can reseat a stubborn tubeless bead with a compressor or replace rim tape if home methods aren't sealing it.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.