Book service WhatsApp us
Cracked sealing tape inside a tubeless-converted spoked wheel at Iron Custom Motors, Cascais
HomeBlogSealing tape in a tubeless conversion: what it looks like after two years
Published 15 August 2026

Sealing tape in a tubeless conversion: what it looks like after two years

A rider came to us with a familiar complaint: the rear tyre was going soft overnight, and every morning started with the pump. No puncture, tyre healthy, valve fine. About two years earlier the wheels had been converted from tubed to tubeless with a special sealing tape — the kind online guides recommend for the job. At Iron Custom Motors in Cascais (Lisbon) we pulled the tyre off and put what we found on camera.

The video

A minute and a half from the workshop: the rim opened up, and the tape as it looks today — dried out, shrunk, cracked along the edges.

Why the tape gave up

These tapes are everywhere, including well-known branded ones, and plenty of guides recommend them. The problem isn't bad luck, and it isn't the installation — it's the material itself. Over time the tape dries out and shrinks; cavities form, especially near the edges, and then cracks. Air finds a way through, slowly at first. In two or three years the wheel starts breathing out: full at night, soft by morning. Exactly what happened here.

A better tape is not the fix

A fresh tape buys a couple of years, nothing more — the same chemistry ages the same way. A spoked rim needs a seal that behaves like part of the wheel: single-component polyurethane, applied in layers, with a service life of decades. It stays elastic the whole time, isn't bothered by water, aggressive environments or UV, and keeps working under constant vibration. Silicone sealants sit on the same "no" list as tapes. We described the whole process step by step in our tubeless conversion guide — three thin layers, a leak test on every spoke, balancing to zero. The conversion costs €100 per wheel.

FAQ

Why is my converted spoked wheel losing air overnight?

If the rim was sealed with tape, that's the first suspect: tapes dry out, shrink and crack with age, and air escapes past the spokes. Slow deflation while parked, with a healthy tyre and valve, is the classic symptom.

How long does rim sealing tape last?

In our case, about two years. As the tape ages, leaks typically begin at two to three years.

Can a tape-sealed wheel be resealed properly?

Yes. The rim is cleaned and sealed with single-component polyurethane — the same conversion we do on tubed wheels.

Is silicone sealant a good alternative?

No — silicone belongs to the same failure family: it shrinks, dries out and cracks. Only single-component polyurethane made for vibration-loaded parts.

Which sealing tape brand is the most reliable?

We don't rate brands. What fails is the material itself: any tape of this type dries and shrinks with age. For a seal measured in decades, tape is the wrong tool.

Wheels and tyres in Cascais

If your converted wheel is soft by morning, bring it in and we'll see what's under the tyre. Iron Custom Motors also runs a full motorcycle tyre service on motorcycle-specific equipment, wheels up to 30 inches. We speak four languages.

WhatsApp: +351 917 961 230 · Tue–Sat 10:00–18:00 · São Domingos de Rana, Cascais · Contact us

Fix your ride & fuel your soul.