So that most of you know the speed rating has more to do with the load capacity of the tire. The 4 things involved in affecting tire life are Load, Air pressure, Speed, & Duration. You can change any one of those variables by altering the others. For example a XZL mich 1600R20 max load is 14540lbs @ 110psi @ 55mph @ sustained duration
Those tires at 120psi @ 25mph @ 2hours run time will yeild MUCH greater load capacity because we changed the charicteristics of the equasion.
Right or wrong this guy likley had fully inflated tires on an empty truck driving faster for a short period of time.
Tires blow due to heat buildup. The above equation is essentailly a HEAT buildup rating. Many of the tires that people on here have blow up are due to 1 the equation, and 2 age of the tire. An older tire cannot work at the same capacity as a new one. HOWEVER i am currently running 35 year old tires on my Jeep. I run them at max air pressure, slow speeds and short distances. They are ugly, weather cracked, and some would say dangerous... I however understand the limitations of these tires so i dont take them down the freeway for more than a mile or 2, and the load on the tires is HALF of what they are rated for.