Originally Posted by
prathmann
It's being ignored by most in this thread because the mechanism for the failure was completely different. In your case the tire sidewall failed - that indicates either than something cut the tire (and that's a possibility even if you didn't notice it at the time) or the tire was defective and had weak cords in the sidewall that failed under the stress of the tube's pressure. But the OP's tire remained intact. In his case, the tire bead first started to separate from the rim (which is when he noticed an unusual sound prior to the blowout) and that allowed a portion of the tube to escape from under the tire bead and then suffer the blowout. The most common cause of this type of failure is improper installation with a bit of the tube being trapped between the rim and the tire bead. That pushes the bead up and off the rim and eventually lets part of the tube escape. But it could also be a rim and tire combination that's incompatible or a defect in either the rim or the tire.
I must disagree with you. In my case, the tire blew off the rim
while going downhill at 35 mph (about 55 kph). I rode on for quite a distance getting the bike under control, with no pressure in the tire. Since there was no apparent damage to the tire before, I came to the conclusion that the cut in the sidewall is due to the sidewall being cut by the rim. Mode of failure: Riding along when BOOM, tire goes off the rims suddenly. Then a series of correcting maneuvers, zig zagging all over the road while I got it under control, all while braking gently not to throw off the balance. I concur with you that something cut the sidewall - but judging from the situation, it was most likely the rim itself after sudden deflation of the tire, making the rim ride on sidewall. Gash location supports such conclusion, as it fits perfectly where the rim would be if the tire was completely deflated. And in my case, the bead also snapped out from the rim first. Or the deflation wouldn't be so sudden, with a bang.
So it looks to me that Michelin might have quality control issues with these tires, much to my dismay. Since they were expensive, and I find them outstanding for my use, it is a pity that I must always have that doubt in back of my head - will the next one blow off again, for no apparent reason? And yes, they are pretty tight fitting on the rim. Ironically, I've never had anything like this happen with much cheaper tires that fit quite loosely on that same rim. Punctures, yes. But a sudden spontaneous blow off, no. And those cheap tires were overinflated by about 20%, while, get this, Michelin was
under inflated by about the same amount when it blew. Enough about quality, if we can call it that.
OP's tire probably remained in one piece because it has reinforced sidewalls, it was a front tire and as such it carries quite a bit lower load then the rear tire in my case, and OP was not going so fast at the time of the blow off. All of those factors considered, I can see how a tire can remain intact. Well that might be a useful advertising tactic for Michelin; our protection is so good that the tire will remain intact even in a case of blow off during riding. As for the rest of the bike and the rider combined, that won't be mentioned here
Tires are from the same family of tires, only difference is in the reinforcement level. Casing is the same, rubber compounds and chord configuration is the same. So two tire of almost practically the same construction blow off the rim instantly without warning, for no good reason; am I the only one here who sees something fishy about those tires quality?