Planemaker

I've been running these tires in 38 for years with no problems until my last purchase this summer.

Simply put, these things leak air between the bead and rim when the pressure gets too low.

Previously, I've been able to complete a ride at lower pressure when a puncture would not seal at 40 psi but would at a lower pressure. On the tires, I had a leak that sealed but, I did lose some pressure (not enough IMO to stop and add air). Five miles later, tire loses all air around the bead and with a shot of CO2, I'm back in the game.