 A further advantage is that because a tubular tyre is an inner tube within the outer tyre casing, it is a "closed system," meaning in the event of a flat the air typically escapes far less quickly than with a clincher.For this reason tubulars are generally regarded as safer to ride than clinchers on fast mountain descents.Conversely, they are also regarded as being "less" safe on long or fast descents, because the heat generated by braking can cause the glue holding the tire to the rim to fail, or the tire to explode.