To apply sealant to tyres, especially for modern tubeless setups, you typically inject it directly into the tyre through the valve stem after removing the valve core. This method ensures even distribution inside the tyre for effective puncture protection and air retention.
Understanding Tyre Sealant
Tyre sealant is a liquid solution, often latex-based, designed to automatically seal punctures in pneumatic tyres. It's primarily used in:
- Tubeless tyre setups: Where the tyre forms an airtight seal directly with the rim, eliminating the need for an inner tube. Sealant is crucial for sealing the tyre to the rim and repairing punctures during rides.
- Inner tubes with removable valve cores: Some riders add sealant to their inner tubes for added puncture resistance, though this is less common than tubeless.
The sealant coats the inside of the tyre, and when a puncture occurs, the escaping air pressure forces the sealant into the hole, where it cures and forms a plug.
Essential Tools and Materials
Before you begin, gather the following:
- Tyre Sealant: Choose a reputable brand suitable for your tyre type (e.g., road, mountain).
- Valve Core Remover Tool: Often a small wrench or integrated into valve caps, used to unscrew Presta or Schrader valve cores.
- Sealant Injector/Syringe (Recommended): Makes precise measurement and injection much cleaner and easier.
- Bicycle Pump or Air Compressor: Essential for re-inflating the tyre.
- Rags or Towels: For cleaning up any spills.
- Safety Glasses: To protect your eyes from sealant splashes.
Step-by-Step Guide to Applying Tyre Sealant
Applying sealant is a straightforward process, but precision helps.
1. Prepare Your Wheel and Tyre
- Cleanliness: Ensure your rim and tyre are clean, especially if it's a new tubeless setup or you're refreshing old sealant.
- Tubeless Ready: If setting up tubeless for the first time, confirm your rim is properly taped with tubeless rim tape and that a tubeless-specific valve stem is installed securely. The tyre should be mounted and seated on the rim first, though sometimes sealant can be added before the final bead seating.
2. Remove the Valve Core
- Deflate the Tyre: Completely deflate the tyre by pressing the valve stem open.
- Unscrew the Core: Use your valve core remover tool to unscrew the valve core counter-clockwise. For Presta valves, you typically only remove the small, threaded pin; for Schrader valves, the entire internal mechanism comes out. Keep the valve core in a safe place.
3. Inject the Sealant
- Shake the Sealant Bottle: Shake the sealant bottle vigorously for at least 30 seconds to ensure the sealing particles are well mixed.
- Measure Quantity: Measure the recommended quantity of sealant using a sealant injector or a measuring cup. While there are recommended quantities for different tyre sizes, remember that adding a little bit more than the minimum can often provide better coverage and extend the sealant's effective life.
- Inject into Valve Stem: Attach the sealant injector nozzle to the open valve stem, or carefully pour the sealant directly into the valve stem if you're not using an injector. Push or pour the sealant slowly into the tyre.
4. Reinstall and Seat
- Replace the Valve Core: Once all the sealant has been injected, replace the valve core by screwing it clockwise back into the valve stem.
- Tighten Securely: Tighten the valve core firmly using your valve core remover tool or the handy valve core remover valve cap that often comes with tubeless valves. Do not overtighten, but ensure it's snug to prevent air leaks.
- Inflate the Tyre: Begin inflating the tyre with your pump or compressor. You should hear the tyre bead "pop" into place as it seats against the rim. Inflate to your desired pressure.
- Distribute the Sealant: Spin the wheel rapidly and vigorously shake it from side to side, then rotate it to ensure the sealant coats the entire inner surface of the tyre, especially the sidewalls and bead areas. You might also ride the bike briefly to help distribute it.
Recommended Sealant Quantities
The exact amount of sealant needed varies based on tyre width and volume. Below are general guidelines:
| Tyre Type | Tyre Width (Approx.) | Sealant Quantity (per tyre) |
|---|---|---|
| Road | 23-32mm | 30-60 ml (1-2 oz) |
| Gravel | 35-50mm | 60-90 ml (2-3 oz) |
| XC MTB | 2.0-2.35 inches | 90-120 ml (3-4 oz) |
| Trail/Enduro | 2.4-2.8 inches | 100-140 ml (3.5-4.5 oz) |
| Fat Bike | 3.0+ inches | 120-180+ ml (4-6+ oz) |
Note: These are general recommendations. Always check the sealant manufacturer's specific guidelines.
Maintaining Your Sealant
Sealant can dry out over time, especially in hot climates or with frequent use.
- Check Regularly: It's good practice to check your sealant levels every 2-6 months, depending on climate and riding frequency. You can often do this by shaking the wheel and listening for liquid sloshing around, or by briefly unseating a small section of the tyre bead to look inside.
- Replenish: Top up the sealant as needed following the steps above.
For more detailed information on tubeless setup and maintenance, you can consult reputable cycling resources such as Park Tool Co. or Global Cycling Network (GCN).
