how to add sealant to tubeless mountain bike tires

Last Updated on August 23, 2025 by Jaxon Mike

If you’re riding a mountain bike with tubeless tires, you know how much of a game-changer the setup can be. Tubeless tires allow you to run lower pressures for better traction and control on the trail, and they practically eliminate the risk of getting a flat tire. But in order to maintain that tubeless setup, you’ll need to periodically add sealant to your tires.

In this comprehensive guide, I’ll walk you through everything you need to know about adding sealant to your tubeless mountain bike tires. We’ll cover the essential tools and supplies, the step-by-step process, and some expert tips to ensure you get the job done right. By the end, you’ll be a tubeless sealant pro and you can keep your bike rolling smoothly on the trails.

Why Add Sealant to Tubeless Tires?

Tubeless mountain bike tires rely on a liquid sealant to seal small punctures and prevent air leaks. The sealant is injected into the tire, where it coats the interior and quickly plugs any holes that develop from thorns, glass, or other sharp objects.

Over time, the sealant in your tires will dry out, evaporate, or get used up as it seals punctures. That’s why it’s important to periodically replenish the sealant to keep your tubeless setup working properly. Neglecting to add new sealant can lead to gradual air leaks and the eventual need to switch back to an inner tube.

So how often should you add sealant? It really depends on a few factors, including:

• The type of sealant you’re using
• How much you ride and the conditions you ride in
• Whether you’ve had any punctures that the sealant has had to seal

As a general rule of thumb, most experts recommend adding sealant to your tubeless tires every 2-6 months, or anytime you notice the sealant level getting low. Some sealants also have an expiration date, so be sure to check the manufacturer’s recommendations.

Gathering the Necessary Supplies

Before you can add sealant to your tubeless mountain bike tires, you’ll need to gather a few essential supplies. Here’s what you’ll need:

• Tubeless tire sealant – There are many different tubeless sealant brands and formulas to choose from, so pick one that’s compatible with your tire and rim setup. Make sure to get enough sealant to fill both of your tires.
• Tire valve core remover tool – This small tool allows you to easily remove and replace the valve core in your tubeless tire.
• Syringe or tubeless injector bottle – You’ll need a way to inject the sealant into your tire, either with a standard syringe or a specialized tubeless injector bottle.
• Tire levers – Just in case you need to remove your tire to get better access for adding sealant.
• Shop towels or rags – To help clean up any spills or mess from the sealant.

Once you have all of these supplies ready to go, you can move on to the actual process of adding sealant to your tubeless mountain bike tires.

Step-by-Step Guide to Adding Tubeless Sealant

Alright, let’s dive into the steps you’ll need to follow to properly add sealant to your tubeless mountain bike tires. This process should only take 10-15 minutes per tire, but it’s important to go slowly and carefully.

1. Prepare the Tire

Start by removing the tire valve core using your valve core remover tool. This will allow you to easily inject the sealant into the tire later on.

Next, give the tire a good inspection. Look for any obvious punctures or areas where the sealant seems to be leaking out. Make a note of these spots so you can focus on them when adding the new sealant.

2. Measure the Sealant

Check the manufacturer’s recommendations for how much sealant to use per tire. Generally, you’ll want to add between 2-4 ounces (60-120 ml) of sealant, depending on the tire size.

Use a measuring cup or the markings on your syringe or injector bottle to measure out the right amount of sealant. It’s better to err on the side of adding a bit extra, as you can always remove some later if needed.

3. Inject the Sealant

With the valve core removed, you can now inject the sealant into the tire. Slowly and carefully inject the sealant through the valve stem, making sure to get it distributed evenly around the tire.

If you’re using a syringe, gently squeeze the sealant into the tire. With an injector bottle, simply screw it onto the valve stem and squeeze the bottle to dispense the sealant.

Once you’ve added all the sealant, give the tire a good shake to help distribute it around the entire interior.

4. Reinstall the Valve Core

After the sealant is in, use your valve core remover tool to screw the valve core back into place. Make sure it’s tightened down snugly to prevent any air leaks.

5. Inflate the Tire

With the valve core back in, you can now inflate the tire to your desired pressure. Use a floor pump or compressor to fill it up, keeping an eye out for any air leaks around the valve stem or bead of the tire.

6. Spin and Rotate the Tire

Once the tire is inflated, give it a good spin and rotate it in all directions. This will help the sealant spread out and coat the entire interior of the tire.

You may also want to tip the bike from side to side to ensure the sealant reaches the sidewalls. Let the tire sit for 5-10 minutes to give the sealant time to seal any small punctures.

Expert Tips for Adding Tubeless Sealant

Here are a few additional tips from the pros to make adding sealant to your tubeless mountain bike tires a breeze:

Use a Tubeless-Specific Sealant

Regular tire sealants won’t work as well in a tubeless setup. Look for a sealant that’s specifically designed for tubeless tires, as these formulas are optimized to quickly seal punctures and remain liquid for longer.

Consider Liquid vs. Latex Sealants

Tubeless sealants come in two main types: liquid sealants and latex-based sealants. Liquid sealants tend to be a bit messier to work with but can seal larger punctures. Latex sealants are a bit easier to use and may last a bit longer, but they can’t seal as large of holes.

Add Sealant Before Inflation

It’s generally easier to add the sealant before inflating the tire. This allows the sealant to evenly coat the inside of the tire before you start riding. If you add sealant to an already inflated tire, it may not distribute as effectively.

Shake the Tire Before Riding

After adding the sealant, be sure to give the tire a good shake in all directions to help spread out the sealant. You can even spin the tire while holding it up to really get the sealant moving.

Carry Spare Sealant on Rides

If you’re going on a long ride or heading to the backcountry, it’s a good idea to carry a small bottle of spare sealant with you. That way, if you get a puncture that uses up all the sealant in your tire, you can quickly top it off and keep rolling.

Conclusion

Maintaining your tubeless mountain bike tires is an essential part of keeping your bike running smoothly and preventing flats on the trail. By regularly adding sealant, you can keep those tires airtight and ready to tackle any terrain.

Just remember to use the right type of sealant, measure the proper amount, and take your time with the process. With a little practice, you’ll be a tubeless sealant pro in no time. Happy trails!

FAQs

How long does tubeless sealant last in mountain bike tires?

Most tubeless sealants will last between 2-6 months in mountain bike tires, depending on the brand, how much you ride, and whether you’ve had any punctures that the sealant has had to seal. Be sure to check the manufacturer’s recommendations and add more sealant as needed.

Can I use regular tire sealant in a tubeless mountain bike tire?

No, it’s best to use a sealant that’s specifically formulated for tubeless tires. Regular tire sealants won’t work as effectively in a tubeless setup and may not provide the proper sealing and longevity you need.

What’s the best way to apply tubeless sealant?

The easiest way is to inject the sealant through the tire’s valve stem using a syringe or tubeless sealant injector bottle. This allows you to evenly distribute the sealant around the inside of the tire without having to remove the tire from the rim.

How do I know if my tubeless sealant is low?

You may notice slow air leaks, hear the sealant sloshing around, or see the sealant drying up and cracking inside the tire. It’s a good idea to visually inspect your tires periodically and add more sealant whenever the level seems low.

Can I add sealant to a tire that’s already inflated?

Yes, you can add sealant to an already inflated tubeless tire, but it’s generally easier to do it before inflating. Adding sealant to an inflated tire may not distribute it as evenly around the interior.