Lost Another Tire Driving Down The Highway

While driving down the highway I heard a puffing sound from behind my Bus.  I was doing 65 in the outside lane and immediately pull unto the shoulder.  When I got back to my tow vehicle, I found that I had blown a front tire.  The last time I did this I broke the axle and had to tow the vehicle to town.  This time I must have caught it in time.  I didn't break any of the internal parts and after putting on the spare, I was able to continue with my trip.  The tire was in good condition and I  have no idea why it decided it had gone far enough.