The best tubeless sealant will keep the air in your tyre for longer and actually fix punctures while you ride. No more inner tubes or patches!

Just what is the best tubeless sealant out there? We put several mountain bike tubeless sealants through the slash test to rate their puncture powers.

Read more: The best tubeless track pumps and inflators

Converting to tubeless is one of the best upgrades you can do to your bike and since most modern rims and tyres are ‘tubeless ready’ you have everything you need to cross over. In fact, the only things you’ll have to buy are a couple of tubeless valves and a bottle of sealant.

As the name suggests, tyre sealant seals punctures but in a tubeless system it also has another function – it coats the inside of the tyre, creating a barrier against air loss. The is because tubeless ready tyres are not fully air tight and eventually leak air through the casing. Some of the first UST tubeless tyres were better at retaining air but they were heavy and expensive and it doesn’t make sense to have them on your bike if you’re not intending to switch. This is why bike manufacturers fit lighter and cheaper tubeless ready tyres and leave the conversion up to you.

Tyre sealant is the life blood of a properly function tubeless system, which is why it’s important to buy one that really works. They are loads of formulations available, with unique and often secret additives to help seal punctures and there’s also a wide range of prices. We have nine on test – all put through the ringer to find that one sweet blend.

Best tubeless sealant for mountain bikes

  • Muc-Off No Puncture Hassle – WINNER
  • Stans No Tubes Race Sealant
  • Orange Seal Endurance
  • Vittoria Pit Stop TNT

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Muc-Off No Puncture Hassle

If you want the best out there, this is it

Price: £29.99 (1000ml)

Pro: Simply the best

Con: Not the cheapest

Muc Off’s oddly named No Puncture Hassle sealant is brand new and, regardless of the size you buy, is one of the most expensive sealants out there. We tested the 140ml sachet, which easily filled our 29×2.4in test tyre but it has a thin nozzle that fits directly in a Presta valve stem reducing mess and waste.

Despite being one of the thickest sealants on test, NPH distributes evenly around the inside of the tyre. When we first squirted the full 140ml there’s didn’t seem like much left in the bottom of the tyre but we needn’t have worried because this luminous pink gunk sealed the 2.75mm puncture in barely a revolution. It also sealed the larger 5mm almost instantly and, while most sealants on test only sealed the sidewall cut temporarily, NPH sealed it permanently and we even manged to re-inflate the tyre after about an hour.

tubeless sealant

Stans No Tubes Race sealant

The original and still one of the best

Price: £32 (946ml)

Pro: Seals more than most

Con: Premium price

Stan’s Race Sealant is definitely worth the small premium over the standard blend. Our heaviest-hitting test riders swear by this stuff – a potent magic formula that heals cuts and makes holes vanish. Stan’s No Tubes Race Sealant is expensive, but contains twice as many sealing crystals and uses bigger particles that can make larger holes air tight.

Latex-based and natural, Stan’s is one of the first and best-known tyre sealants. Its popular original formula is proven to work without the familiar issues of drying out prematurely or simply not being able to plug small holes and rips in damaged tyres. Race formula is only available in bigger tubs (just under a litre for just over thirty quid), but the extra price over No Tubes standard sealant is worth it since it’s worked extremely well for us on multiple occasions; plugging big holes fast before we’ve lost all air, which is something that rarely happens out on the trail with other sealants.

tubeless sealant

Orange Seal Endurance

Really effective at sealing small and medium sized punctures

Price: £40.00 (909ml)

Pro: Stays liquid longer than most

Con: Struggles with larger cuts

Orange Seal claims its Endurance sealant can last up to 120 days before it dries out, which is about four times as long as its regular stuff and you only pay an extra £1 across all the sizes for this increased durability. At £7 per wheel, only Muc Off’s sealant is more expensive but Orange Seal Endurance remained totally fluid in cold temperatures and easily sealed the 2.75mm and 5mm holes in our test tyre. The company claims it will seal slits up to 19mm and, while it did plug our 8mm cut, it was only temporary, when we added a bit of weight the tyre split open again. Like a lot of sealants, we reckon you’re just going to have to work it into the cut repeatedly and let it partially dry out if you’re trying to get going out on the trail.

Vittoria Pit Stop TNT

Excellent if you just want pinch protection

Price: £22.99 (500ml)

Pro: Seals tyres fast when setting up

Con: Doesn’t seal cuts very well

Pit Stop TNT is a thin sealant and it retained this viscosity when chilled, however we noticed a skin had formed over the sealant when it was heated. In our torture chamber the Pit Stop TNT sealed the 2.75mm puncture after barely one revolution and did the same for the 5mm hole initially but it eventually when we put weight on the tyre. It didn’t seal the sidewall cut either we played around with positioning the slash rotating it to the bottom where it could submerge in sealant but it didn’t help.

Pit Stop TNT plugs holes quickly but lacks the larger particulate to seal bigger cuts and sidewall tears. You could easily add some home-made additive to boost its clogging power but there are cheaper alternatives where you could do the exact same thing.