Originally Posted by
DX-MAN
THIS. Happens without warning, on just about any type of rim, with almost any type of tire. It happened to me THE ONE TIME I didn't have a perfect hook-up between my Michelin tire and Sun rim. Changed tires on those bad boys probably six times in two months over the last winter.
EXACTLY! The tyre is a stiff, unyielding envelope surrounding the tube. IF the tube is fully encased inside the tyre, there is very little expansion of the tyre-casing within normal operating pressures. The tyre-casing simply cannot expand that much. Compared to pumping up just the bare-tube, just 5psi will have it expand 10x bigger than the tyre. IF some of that tube is allowed to squeeze out a gap anywhere so that it's not surrounded by tyre, then the +100psi pressure will cause the tube to expand 100x bigger than the tyre and ... >BOOM!!!!<
Typical commonly-accepted idea is that it takes double the pressure printed on the tyre's label to expand a properly-installed tyre's bead just slightly enough to push it over the rim. Then the tube is no longer contained inside the casing and >BOOM!!!!<