Quick answer: A bead leak is air escaping where the tyre’s edge (the bead) meets the rim, not through a hole in the tread. It’s usually caused by corrosion, dirt or a kerbed rim breaking the airtight seal. The fix is to demount the tyre, clean and de-corrode the bead seat, apply fresh sealing paste and re-seat it — or replace a damaged rim.

What is a tyre bead leak?

Your tyre doesn’t seal against the rim by magic. The bead — the stiff, wire-reinforced inner edge of the tyre — is pressed hard against a machined ledge on the wheel called the bead seat. Air pressure inside the tyre holds that seal tight. A bead leak happens when the seal between bead and rim is broken somewhere around its circumference, so air seeps out slowly even though the tread and sidewall are perfectly intact.

That’s why a bead leak is so frustrating to diagnose: there’s no nail, no screw, no obvious damage. The tyre just keeps needing air. If you’ve already ruled out an object in the tread, a bead leak (or a valve leak) is the next suspect. Our guide to slow puncture diagnosis walks through the full elimination process.

What causes a bead to leak air?

Most bead leaks trace back to something interfering with the metal-to-rubber seal:

Cause	What’s happening
Rim corrosion	Aluminium oxide (white, chalky build-up) or rust forms on the bead seat and creates tiny channels for air to escape. The most common cause on older alloy wheels.
Dirt & debris on the bead seat	Sand, mud or old tyre paste left on the ledge stops the bead from seating flush.
Kerbed or bent rim	A knock from a kerb or pothole can deform the rim lip so the bead no longer sits evenly.
Damaged or stretched tyre bead	The wire bundle in the tyre can be damaged during a rough fitting or by running very underinflated.
Perished bead rubber	On an old tyre the rubber at the bead hardens and stops conforming to the rim.

Corrosion is by far the leading cause, and it’s worse in coastal and salt-air parts of Australia. If your wheels show white powdery build-up, read our dedicated guide on corroded rims causing air loss and on why alloy wheels corrode and go white.

How do you know it’s the bead and not a puncture?

The classic test is a soapy-water check. With the tyre inflated to the correct placard pressure, spray a mix of dishwashing liquid and water right around the join between the tyre and the rim, on both the outer and inner faces. Bubbles forming along the bead line confirm a bead leak. If bubbles appear at the valve, it’s a valve problem; in the tread, it’s a puncture.

A bead leak is typically slow — you might lose a few psi over days or a week — which is exactly the pattern that also lights up a tyre pressure monitoring system gradually rather than suddenly. A sudden, fast deflation points to a puncture or a nail in the tyre instead.

How is a bead leak fixed?

This is a workshop job, not a roadside one, because the tyre has to come off the rim. A tyre fitter will:

1. Demount the tyre from the wheel.
2. Clean the bead seat — wire-brushing or sanding away corrosion, dirt and old paste until the ledge is bright and smooth.
3. Treat and seal the surface. Where corrosion was present, a bead sealer is applied around the seat.
4. Re-seat the tyre with fresh mounting paste and reinflate, then re-check with soapy water.

Expect it to take roughly 30–45 minutes per wheel. If the rim is bent, cracked, or so badly corroded that pitting has eaten into the metal, cleaning won’t hold a seal and the wheel needs professional repair or replacement — a knock from a kerb is a common trigger, so it’s worth reading up on kerb damage and structural harm. Many Australian tyre retailers such as Bridgestone Australia handle bead-seat cleaning as part of a tyre fit.

Can you fix a bead leak yourself?

Realistically, no — not properly. Demounting and remounting a tubeless tyre safely needs a tyre machine, and reinflating a fully unseated bead can be dangerous without the right equipment. Bead sealer squirted around the outside of a mounted tyre is at best a very short-term bodge that traps the corrosion underneath. The correct, lasting fix is to have the tyre removed and the seat cleaned. It’s inexpensive, so it’s not worth risking a slow leak becoming a flat on a highway.

How do you prevent bead leaks?

Have the bead seat cleaned every time new tyres are fitted, choose corrosion-resistant wheel finishes if you live near the coast (see wheel finishes for coastal conditions), wash salt and road grime off your wheels regularly, and don’t run tyres badly underinflated — which stresses the bead. Keeping a close eye on your spare’s pressure matters too, since a neglected spare often develops a slow bead leak while it sits.

Bottom line: A tyre that loses air with no puncture is very often leaking at the bead — the seal between the tyre and the rim — usually from corrosion, debris or a damaged wheel. It won’t fix itself, but a fitter can demount, clean the bead seat and reseal it cheaply. If the rim is pitted, bent or cracked, replace it.

Frequently asked questions

Is it safe to drive with a bead leak?

A slow bead leak is usually safe for short trips if you keep the tyre inflated to the placard pressure and check it often, but get it fixed promptly. Driving on a tyre that keeps going underinflated builds heat and can damage the casing.

How much does it cost to fix a bead leak in Australia?

As a guide (2026), cleaning and resealing a bead seat is often around $25–50 per wheel, similar to a puncture repair. Confirm with your local fitter, as prices vary by store and wheel type.

Will tyre sealant fix a bead leak?

Liquid sealant is designed for tread punctures and won’t reliably seal a corroded bead. It can also make a proper repair messier. Have the bead seat cleaned instead.

Why does only one wheel keep losing air?

Corrosion, a kerb strike or debris tends to affect one wheel at a time, so a single leaking bead is common. Have that wheel demounted and the seat inspected.

Figures and prices are a guide for 2026 and can change — confirm current pricing and any legal roadworthy requirements with your tyre fitter or state road authority.