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Oh no! You've just noticed the air is hissing out of your tyre. This can be one of the most frustrating things to happen to your car, especially if you're on a budget.
With a new tyre costing between $100 and $500 per corner, it can cause some unnecessary stress.
But your tyre can be repaired for as little as $10 depending on what sort of puncture you have.
We take a look at when a tyre is and isn't repairable.
When you get a puncture in your tyre, the fitter will perform one of three repairs.
The most common is a rubber strip. The repairer pulls the puncture-causing object out of the tyre and pierces the puncture with a reamer to enlarge the hole.
A sticky rubber strip is then fed through an insertion tool and rubber cement is added to improve the seal. The strip is then pushed into the puncture location.
The insertion tool is then pulled out quickly, leaving the rubber strip in the hole as the glue seals up the section. The excess rubber is trimmed off, and you are left with a repaired puncture.
The next most popular option is a mushroom plug. It follows the same steps as the rubber strips, but uses a mushroom-like sealing system that expands in the puncture location and seals from the inside.
The last puncture repair is called an internal patch. It is less common on road cars due to the time and materials needed to make it, but expensive performance tyres will often get this repair.
It involves taking the tyre off the wheel, cleaning the punctured area, inserting a plug, and then applying a rubber cement patch on the inside of the tyre before remounting it and balancing it.
When can a tyre puncture be repaired?
Typically, small punctures can be repaired as long as they have not torn the tyre and disrupted its overall structure.
Bridgestone Tyres Australia says, "To ensure optimal driver safety, a tyre repair service can only legally be done if the tyre suffers a penetration within a specified area of tyre tread".
That specified area is from belt edge to belt edge, where the tyre tread isn't curving. If you receive a puncture on the curved edge or the sidewall, then you will need a replacement tyre.
This is because the tyre's sidewall takes the load of the car. Once the structure is compromised, it's unlikely that it will seal, and if it does seal, it will not have the same flex characteristics.
Most tyres cannot be repaired if the puncture angle is above 45 degrees. This means that if you run over a nail and it enters your tyre sideways, most shops will say that the tyre will need to be replaced.
Puncture repair kits only allow for hole repairs up to 6mm. If the puncture hole is too big, the repair will not seal properly.
Shops will also not repair the tyre if it has low tread, has been repaired three times in the past, or has been damaged by driving on it after it has gone flat.
That last one is important. If you have a flat tyre, it's imperative to go straight to a tyre shop or swap out for a spare because driving on it will damage the sidewall, and the whole tyre will need to be replaced.
Can a run-flat tyre be repaired?
Contrary to popular belief, run-flat tyres do go flat. The name comes from the fact that you can drive on it for a short distance while it has a puncture.
But can they be repaired? Mitchell Golledge, Head of East Region Asia Pacific for Continental Tyres, says that only some brands permit the repair of run-flat tyres.
"Motorists are advised to cautiously proceed to the nearest reputable tyre retailer. Such retailers can advise whether the tyre can be repaired or whether it needs to be replaced," explained Golledge.
"Some tyre manufacturers do not condone the repair of their run-flat tyres under any circumstances, while others advise that repair under certain stringent conditions may be possible."
For the most part, if the tyre is repairable, a run-flat should not be repaired more than twice.
Zane Dobie comes from a background of motorcycle journalism, working for notable titles such as Australian Motorcycle News Magazine, Just Bikes and BikeReview. Despite his fresh age, Zane brings a lifetime of racing and hands-on experience. His passion now resides on four wheels as an avid car collector, restorer, drift car pilot and weekend go-kart racer.
