Tubeless Tire Sealant: A Simple Guide

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Ben Jones

Bike Maintenance, Other

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Do you want to keep your bike rolling smoother, faster, and longer? Discover the amazing benefits of using tubeless tire sealant and say goodbye to slow punctures, flats, and wasted time. In this blog post, we’ll explain why you should make the switch to tubeless tires, how tubeless sealant works and how much you need to use to stay puncture-free.

What does tire sealant do?

Tire sealant is a liquid solution that is designed to fill small punctures instantly, often before you even realize they exist.

Inject the liquid into your tires and, as you cycle along, the wheels will turn and the sealant will roll along with them, completely coating the inside tread area of the tires.

When you get a puncture, the pressure inside the tire forces air out the tire. With a normal inner tube setup this would leave you with a flat tire and either a frustrating half hour with a patch repair kit…or a long walk home if you hadn’t brought one.

Neither of which is particularly appealing.

In contrast, a tubeless tire dosed up with sealant behaves very differently.

Take the same puncture. Air pressure in the tire still pushes air out of the hole in the rubber. As the air shoots out of the air though it also carries the liquid sealant with it. The liquid portion of this escapes, but the sealant also contains latex or carbon fibers and these bunch up and get trapped at the puncture site forming an airtight seal.

Often times this happens so quickly that you won’t even notice you’ve had a puncture and can just keep on pedaling.

Until bulletproof bike tires exist, this just might be the next best thing.

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The benefits of tubeless vs inner tubes?

I recently had the opportunity to test out a pair of tubeless tires on my bike, and the difference in performance was night and day compared to the inner tube tires I had been using. Tubeless tires offer several benefits over traditional inner tubes, so if you’re considering making the change, here’s what you need to know.

Fewer punctures

Of course, the biggest advantage of tubeless tires is that they’re far more puncture-resistant due to the absence of an inner tube. Pinch flats (AKA “snake bites), nails, sharp rocks, glass shards…these all rapidly become things that you no longer need to worry about as the sealant does its job.

Lower rolling resistance

Inner tubes become stiff under high pressures and this can cause you and your bike to travel slower as the tires go up and over bumps in the ground. Dump the inner tubes for a tubeless setup however and (along with reducing tire pressures – see below) your tires will be able to soak up the bumps, allowing you and bike to travel at faster speeds for the same effort.

Better traction on loose terrain

Tires at lower pressures give better grip on loose surfaces and so many mountain bikers and gravel riders cycle with softer tires. Trouble is that low pressures with inner tubes often results in pinch flat punctures where the side of the tube is nipped between the tire and metal rim. It leaves a distinctive two slash pair of holes that is difficult to repair and takes the fun out of a trail.

Because a tubeless setup doesn’t have an inner tube to puncture the tires can be run at much lower pressures without the risk of getting a snake bite.

Less time wasted mending punctures

Yeah, it’s an obvious one, but the less time I spend repairing punctures the happier I am!

And, it’s not only time that you’ll save, it’s cold hard cash too. No more inner tubes to buy, no more patch repair kits. Happy days.

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The downsides of tubeless

Whilst tubeless tires are fantastic, they’re not without their disadvantages. So, before we get too excited about them, let’s consider these.

Setup costs can be expensive

Inner tubes are cheap to buy (especially in bulk) and, with a little patience, it’s possible to repair a tube multiple times so it can last for a long time. In contrast, with a tubeless setup, you’ll obviously need to buy a bottle of sealant, plus kit including a valve-core remover and sealant injector.

Tricky to install right

Whilst setting up tubeless tires is something that’s absolutely DIY-doable, it’s much easier if you’re comfortable doing regular bike maintenance (particularly some of the trickier bike repair jobs). If not you’ll likely find that this is both a messy job and one that it’s easy to get wrong.

If in doubt about your ability level, then it’s generally something that’s best left to the experts at your local bike shop. They have the kit and the expertise, and they probably do this job day in and day out.

Won’t guard against big punctures

Tubeless sealant will normally protect your tires from punctures caused by small things (think: nails, broken glass and goat heads) but, unfortunately, it’s not going to keep you rolling over the big stuff. Gashes and tears, and even holes of more than ¼” or 6mm, will mean a new tire.

That said, punctures like that would mean a new tire purchase whether you had a tube fitted or not.

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Are all tubeless sealants the same?

Start looking around for a bottle of sealant to buy and you’ll soon discover that there are lots of brands to choose from. Orange, Muc Off, Ride on, Stans… the list goes on and on. Are they all the same? How do you choose between them?

There are two main types of sealants, those that use latex rubber and those that don’t.

The most common form, latex-based sealant, uses the coagulating properties of natural latex to block punctures. Air pressure causes the water or ammonia solution (that the latex is suspended in) to evaporate, leaving latex molecules to knit together and seal the hole. However, over time the water/ammonia solution will naturally evaporate, leaving a rubbery mess inside the tire that won’t plug holes and will need to be scraped out.

Latex-free sealants rely on a thicker liquid with a variety of different sized sealing particles to fill in holes by actually plugging them from the inside. These sealants last longer but may not be as effective at plugging punctures.

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How much sealant to put in tubeless tires?

The amount of sealant that you need to use will depend on whether this is a new tire install or topping up an existing tubeless tire. A fresh tire will need around 50% more sealant that an existing tire needs as some of the sealant will go round the tire interior filling up all the minor imperfections, before a puncture has even happened.

How much tire sealant to use

Road bike

700c x 25/28mm

30-45ml

1-1.5 fl oz

Gravel/Commuter

700c x 35/38/40mm

60-75ml

2-2.5 fl oz

Mountain bike

26”/27.5” x 2.1”/2.5”

60-75ml

2-2.5 fl oz

Mountain bike

29” x 2.1”/2.5”

105-140ml

3.5-5.0 fl oz

Fat tire bike

26”/27.5”/29” x 3.7”/5.0”

140-240ml

5.0-8.0 fl oz

rule of thumb for sealant is to add more: err on the high side
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Tire sealant how to use

As previously mentioned putting sealant into tubeless bike tires is not the easiest of jobs. However, if you’re comfortable with bike repair projects, have a suitable space that you don’t mind getting messy (sealant and your mom’s best carpet doesn’t go together well!) then here are the details of how to top up your tire sealant.

  1. Deflate the tire, use a core removal tool to speed up this step
  2. Fit the nozzle of the sealant bottle or pouch to the coreless valve and fill with the appropriate amount of sealant (a sealant injector can be useful in measuring this accurately)
  3. Fit the core valve back into place
  4. Inflate the tire to the pressure you need
  5. Give the tire a spin to allow the sealant to flow around the entire inner tread surface

That’s it! You’re done and ready to head out cycling.

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Frequently Asked Questions (FAQs):

How long does tubeless sealant last?

Sealant manufacturers typically say that their bottled sealants will last around 4 years from the date they were first opened. After this you may find that the sealant either doesn’t flow as well around the tire, or doesn’t plug punctures the way it used to. Better to buy a smaller bottle and use it in one go if you can, than have an old bottle sitting on a shelf gathering dust for years.

Is tire sealant bad for tires?

Tire sealant won’t damage your tires. In fact any existing cracks or imperfections inside your tire will be sealed up by the sealant.

Tire sealant for cracked tires (does it work?)

Unfortunately not. Cracks on tires generally show on the exterior sidewall. Because sealant flows around in the INSIDE of the tire it won’t be able to get to those cracks and seal them up. If you have cracked tires it’s usually best to replace them with new tires, rather than risk a blow out.

What happens if you put a tube in a tubeless tire?

It will work perfectly fine! In fact, it’s a good idea to carry a spare tube with you when you have a tubeless setup. That way, any large punctures that the sealant can’t seal will still be repairable by fitting an inner tube as a temporary measure to get you back to base.

What to do if your tubeless tire goes flat

If your tubeless tire goes flat, hop off the bike and check for any large areas of damage. If there are big tears or rips then you’ll likely need a fresh tire. If there’s no obvious damage, then give your wheel a few slowish spins to make sure that the sealant can reach the full inner surface area of the tire. That will allow it to find (and hopefully plug) any small punctures. Give it a few minutes to make sure the plug is fully set. Then re-inflate your tire and check that it’s holding pressure before you set off again.

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