What to do if you get a nail in your tyre?
Some things just don’t belong together: orange juice after brushing teeth, political talk in the pub, and your tyres and nails.
If you do find yourself with a nail poking through into your tyre, there here are a few tips to help you decide what to do next, all while mitigating danger, stress and sometimes cost.
How do I know if my tyre is going flat?
Your first sign a tyre is suffering what’s known as a ‘slow leak’ puncture will likely be either from a visual inspection or notification from the vehicle’s on-board computer.
Many modern cars come fitted with tyre pressure monitoring systems, and these can range in intricacy from a simple warning that a tyre’s pressure is low, to informing drivers of exactly which tyre is running low, and with some even displaying exact pressures for each tyre in real time.
A visual inspection of a tyre with low pressure, even if the source of the puncture is not observable, will show the tyre ‘bulging’ away from the wheel at the point where it touches the ground. If there is a noticeable bulge, or the tyre’s sidewall appears noticeably shorter at the bottom than it does at the top, then there’s a good chance it’s suffering from low pressure.
This can be additionally confirmed by pressing against the tyre’s sidewall (the vertical section around the wheel) with your thumb. If the tyre you suspect to be low on pressure feels much squishier than others, that’s a pretty good sign it might be.
For more precise measuring and confirmation, tyre pressure gauges are relatively cheap and available from most auto parts stores and service stations. These compact tools can be kept at home or in a car’s glovebox, and glovebox and are able to give a precise pressure read-out with ease.
Identify how serious the leak is
Not all punctures are created equal, and establishing if a leak is major can help determine what you should do next.
Due to the pressure tyres are inflated to, they can hold a considerable volume of air and sometimes take many days or even weeks to show signs of deflation due to a minor leak.
If you’re not able to replace the tyre right away, increase its pressure to the manufacturer’s specification and continue to observe and test over the coming hours and days.
While it’s always good practice to replace or repair a tyre that’s suffered a puncture as soon as possible, a very slow loss of pressure can facilitate a drive to a location for either replacement or repair of the tyre.
If the leak is major and the tyre is losing pressure quickly, do not risk driving it. The loads a tyre is exposed to while driving will only force air to leak faster, and a tyre is only designed to operate properly at its designated pressure. Never drive on a severely deflated tyre.
What do I do if my tyre is completely flat?
If you don’t have access to an inflator at home, or if attempts to reinflate the tyre have revealed it will not hold air, your options become limited.
Cars will come with either a full-size or space-saver spare wheel, or – increasingly common in modern and electric cars – a tyre repair kit. Both space-saver wheels and repair kits are seen as temporary fixes, designed to get you moving again for a short period, and ideally straight to a tyre shop.
If you don’t have a spare wheel or repair kit, you can remove your wheel and take it directly to a tyre shop for repair or replacement of the tyre.
Never attempt to drive on a flat tyre, even for small distances. Safety concerns aside, you face doing even more damage to the tyre – such as causing pinches and large tears – and can end up turning a tyre eligible for repair into one that needs replacement.
Does my tyre need repair or replacement?
Depending on how severe and where puncture has taken place, a nail through your tyre may not be cause for a potentially costly replacement.
The consensus for a repairable hole is generally that it is no more than 6mm in diameter, and must be on the treaded part of the tyre. Due to its design, repair should absolutely not be attempted on a tyre’s shoulder or sidewall sections.
Repairs can be done by a qualified tyre shop technician, or at home using relatively simple and inexpensive repair kits. These are generally split into two types: one that injects a sealing goo and pressured air into the tyre’s internals; and one which requires manual insertion of a rubberised sealant from outside.
