A slow puncture is a gradual loss of air, often so slow you only notice the tyre looking soft every week or two. The usual culprits are a small nail or screw in the tread, a leaking valve, a corroded or buckled wheel rim, or a previous repair that's failing. Caught early, most are cheaply repairable, which is why it pays to act on the first sign rather than just topping up.
Signs of a slow puncture
Slow punctures rarely announce themselves, but the clues are consistent:
- One tyre that repeatedly needs topping up.
- A TPMS warning light that comes on, especially in cold weather.
- The car pulling slightly or feeling vague at one corner.
- A faint hiss, or a nail head you can see in the tread.
Common causes
Sharp objects like nails and screws are the most common cause. Valve faults let air seep out around a perished or damaged valve. Rim corrosion, the "alloy rim leak", is common on older alloy wheels where the bead no longer seals properly. And a poor previous repair can weep air over time. A fitter's internal inspection is what pins down which it is, because more than one of these can be present at once.
Why you shouldn't ignore it
A slow puncture that's topped up and ignored can fail suddenly, and driving on a repeatedly under-inflated tyre causes uneven wear and overheating. If it goes fully flat and you drive on it, a repairable puncture becomes a new tyre. The cheap fix has a short shelf life, so the sooner it's seen, the better. TyreSafe recommends checking pressures monthly to catch slow losses early. There's also a hidden cost: a tyre that's chronically a few PSI low wears its shoulders and wastes fuel the whole time you're nursing it.
How it's found and fixed
Finding a slow leak takes more than a glance, which is why a proper check matters. The wheel comes off and the tyre is removed, then it's checked in a water bath or with a leak spray to pinpoint exactly where the air is escaping, the tread, the valve, or the rim bead. Once the cause is found, it's either patched to standard if it's a tread puncture in the safe zone, or the valve or rim seal is sorted. A leak from corrosion at the rim, for instance, needs the bead cleaning and resealing rather than a patch. Our mobile fitters do all of this at your home or work, usually in well under an hour.
Book a slow puncture check
If a tyre keeps going soft, don't keep topping it up and hoping. We come to you across the UK, find the cause, and fix it properly on the spot. Book a check.
