I had a normally-pressurized Dunlop SP20 fail on me once. 1000 miles on my new '97 Civic DX, 70 on the Interstate, and Ka-Blooey! Had to regain control of the car and pull over.
The tire completely separated into 2 pieces: 3/4 of the tread portion, and 1/4 of the sidewall in a completely even separation. No previous damage, no warning. I investigated it and it looked like a weak manufacturing process where the sidewall met the tread. No warranty coverage - Dunlop Corp. lawyers calling instead of customer service.
It happened on the July 4th weekend, so getting to work, my spare wore-out and I had to buy another tire out-of-pocket when the tire-shop opened, and bought salvage tire/rim for a full-sized spare.
I vowed never to buy Dunlop again, and haven't since.
I sent the tire to them for analysis and never heard back (despite my several calls and threats to report to the BBB, Attorney Genl., etc.)
Pics are documented.
LSS - the tire failed from within: bubbled and weakened at a seam. Water can do it, striking a hard surface/object can, overpressurization. But I've seen many name brand, normal-pressure tires bust belts prematurely as well. It's a crap shoot.
RH77