A tyre that loses a few PSI a week, holds pressure under a soapy-water test on the tread, and shows nothing on inspection is very often not punctured at all. It's leaking where the tyre bead meets the rim — and that's what bead sealer is for.
What bead sealer does
Bead sealer is a brushable compound applied to the tyre bead and the rim flange before the tyre is seated. It fills the microscopic gap between the two surfaces, and stays flexible so the seal survives temperature swings and flexing. It is not a puncture repair, and it is not a substitute for fixing a damaged rim.
When to use it
- Corroded alloy rims. The most common case in UK workshops. Alloy corrodes at the bead seat, especially on winter-salted roads, leaving a pitted surface a bead can't seal against.
- Older steel wheels with surface rust at the flange.
- Any tyre being refitted to a wheel with a known slow leak that isn't a puncture.
- Agricultural, plant and trailer tyres, where rims live a harder life.
When not to use it
Bead sealer will not rescue a cracked rim, a buckled flange, or a tyre with sidewall damage. It also won't fix a leaking valve — if you're already breaking the bead, fit a new TR414 snap-in valve while the tyre is off. Valves are consumable and replacing them at every tyre change is standard practice.
How to apply it
1. Confirm it really is a bead leak
Inflate, then run soapy water around the full circumference of both bead seats. Bubbles at the rim edge confirm the diagnosis. Check the valve at the same time.
2. Break the bead and clean the rim
This is the part that determines whether the repair lasts. Wire-brush the bead seat back to clean metal, removing corrosion, old sealer and rubber residue. On badly corroded alloys, a light abrasive pass gives a far better key — a flexible abrasive pad works well into the curve of the flange. Wipe clean and let it dry fully.
3. Apply to both surfaces
Brush an even coat onto the rim bead seat and onto the tyre bead itself. Even coverage matters more than thickness — a heavy coat takes longer to cure and can squeeze out when the bead seats.
4. Fit and inflate promptly
Refit the tyre and seat the bead while the sealer is still wet, so it spreads into the joint. Inflate to the seating pressure, check the bead is fully home all the way round, then set to the vehicle's specified pressure.
5. Let it cure before release
Follow the container's cure guidance. Check pressure again before the vehicle leaves.
Buying for a workshop
Bead sealer is a steady-use consumable rather than an occasional item, so it's usually worth buying by the case. We stock Patch Rubber bead sealer in 946ml and in packs of six for busier bays.
For repairs proper — as opposed to sealing — see our Rema Tip Top radial patches and the wider tyre consumables range.
