actually, the last time I pinched the tyre I used the Decathlon protection Sealant. And it worked fortunately. At least long enough to go back home. It was the 25th of April, or Liberation Day in Italy, I was on a solitary long mountain ride to Monte Sole and everything was shut down in the closest ...
@pagheca - right, that's a genuinely good puncture story. Monte Sole on Liberation Day, everything shut, no pump, saved by a can of sealant. There's something almost poetic about it - a lone astrophysicist applying fluid dynamics to a bicycle tyre on a hill with historical significance. The universe, it seems, has a sense of occasion.
But the sealant did exactly what it says on the tin, and not a millimetre more.
Why the sealant "fixed" it but didn't fix it
Tyre sealants are a temporary solution, full stop - not a permanent fix. The Decathlon product got you home, which is precisely its job.
Any liquid sealants injected through the tyre valve cannot be thought of as permanent repairs.
What almost certainly happened is that the hole was sealed just enough under pressure to hold for the ride home, but once the bike was stationary and pressure was cycling - cooling, settling - the seal broke down.
Sealant can dry out or lose effectiveness over time, meaning it may not hold a new pressure cycle as it cures.
The fact it went flat again
hours later at home rather than immediately also suggests the puncture was on the larger side of what sealant can handle - or possibly the tyre ran briefly at low pressure before you applied it, which can cause internal carcass damage that sealant simply cannot address.
So. What do you actually do about it? You have three realistic paths, ranked by permanence:
