Punctures from nails or debris
Sharp objects like nails, screws or glass are a common cause of a slow leak, and the puncture isn't always obvious just from looking at the tyre.
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Common Causes of a Slow Tyre Leak
Why a tyre might be slowly losing air — several possible causes, and why a leak always needs a proper inspection rather than a guess.
A tyre that keeps losing air without an obvious flat can be one of several different things — and telling them apart usually needs a proper look, not a guess.
Damaged or worn valve stems
Valve stems wear out over time, and a crack or perished seal can let air escape gradually without anything else being wrong with the tyre.
Bead seal issues
The bead is where the tyre meets the rim, and corrosion or an imperfect seal there can cause a slow, sometimes hard-to-spot leak.
Corroded or damaged rims
Potholes and kerb strikes can bend or corrode a rim, creating tiny gaps that let air escape slowly over time.
Temperature changes
Tyre pressure naturally drops as the temperature falls, which can look like a leak during colder spells even when the tyre itself is fine — worth ruling out before assuming there's damage.
Sidewall damage
Kerb strikes and road debris can damage a tyre's sidewall in ways that aren't always visible, and this can be a more serious safety issue than a tread-area puncture.
An ageing tyre
Rubber degrades over time, and an older tyre can start to lose air more easily even without an obvious injury.
A faulty TPMS sensor
Where a vehicle has a tyre pressure monitoring system, a faulty sensor can itself cause a small leak around its seal, separate from anything wrong with the tyre.
Why it needs a proper look
Because a slow leak can come from several different causes — some straightforward to fix, others needing more than a repair — we can't tell you which applies to your tyre without inspecting it. If you're noticing repeated low pressure, uneven wear, or a dashboard warning light, it's worth getting it checked rather than continuing to top up and hope it holds.
See our puncture repair service for suitable repairs, or our West Lothian coverage page to arrange a visit.