How do tyre sealants work?

Tyre sealants are a handy way to keep your tyre inflated after it’s picked up a puncture. However, with a few options available, it’s important to pick the right sealant for your needs. Here’s everything you need to know.

Pre-puncture tyre sealant

Getting a puncture is both deflating for you and your tyre and can leave you stranded.

However, with the help of a pre-puncture tyre sealant, you can get your vehicle to a point of safety where you can get the puncture repaired.

The pre-puncture tyre sealant is a material that goes into the tyre when it has not yet been damaged and stays inside ready to go to work if a puncture should ever occur. When the tyre is punctured, the sealant automatically patches over the wound, keeping the air in the tyre so you can continue driving on it.

This is good because it allows you to get to a place of safety where you can get the puncture repaired.

However, they can do such a good job that you may not notice you’ve punctured, so it’s important to regularly check your tyres. Remember, a sealant is only designed to keep you on the move for a short distance, and even if your tyre remains well inflated, it still needs repairing.

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Post-puncture tyre sealant

In a case of ‘does what it says on the tin’, post-puncture tyre sealant is injected after a puncture has occurred.

This will plug the hole and allow you to reinflate the tyre, before driving to a location to get the puncture repaired.

You’ll have to wait a little while for the sealant to work, but with a post-puncture sealant you’ll definitely know when you have a puncture.

How do tyre sealants work?

With both types of sealant, the tyre sealant works by filling the hole caused by the puncture, and then curing, similar to any other kind of glue or filler.

You might be able to see some of the sealant from the outside of the tyre, as it sometimes oozes through the puncture to leave a visible scar on the tyre tread. This will tell you if your tyre is damaged. Then you can avoid driving on it for any longer than you need to.

Tyre sealants are also only designed to plug holes and won’t work on more severe issues such as a rip on the sidewall.

How long do tyre sealants last?

Neither solution should be considered a permanent repair. It is just a temporary patch job to get you to a safe place, where you can get the tyre permanently repaired or replaced.

Any permanent tyre repair requires that the tyre be completely removed, checked for structural damage, and only refitted if it’s in a safe condition.

Because of this, injecting sealant into the valve or letting a pre-puncture tyre weld seal a puncture can never be considered an adequate permanent repair. What’s more, you must always be sure to get the tyre removed and looked at by a professional.

There is also the question of how long pre-puncture tyre weld lasts inside the tyre. If your wheels are several years old, there is the risk that the sealant is past its best and would be unable to fully seal a puncture if one were to occur.

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Advantages of sealants

So, should you use tyre sealants? There are clear benefits of doing so, such as:

  • Complete your journey or find a place of safety on the existing tyre
  • Pre-puncture sealants activate automatically, preventing delays
  • Post-puncture sealants can be administered yourself, wherever you are

As long as you remember that they’re only a temporary fix, tyre welds can be an effective way to safely carry on driving to a point where you can get a tyre repaired.

If you choose the pre-puncture sealant, it’s important to regularly check the tyre, as a puncture may not be obvious. You’ll also need to carry a tyre inflator with you to keep the tyre inflated above the legal limit.

Find tyre inflators

Here at Halfords, we have over 600 garages nationwide, and will fit any new tyres for you. You can find your nearest Autocentre here, or why not explore our full range of motoring services over at

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Same day tyre fitting

Did you know that we now offer same day tyre fitting service across our garages nationwide? Simply book online before 1pm and we can replace your tyres the same day to help you get you back on the road safely and swiftly. Please note that availability varies by location. For more information, please head on over to our dedicated same day tyre fitting page where you can find answers to frequently asked questions, choose the right tyres for your vehicle and book your appointment.

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