I go along with Eggalitarian that sometimes things just happen….. but…. two tires on one side on the same trip? And from you initial comment, it appears the original Marathon tires also blew.?
Does that mean that you’ve had four tires “explode” or come apart???
And were they all on the drivers side?? There must be some hidden reason and it doesn’t sound like it’s necessarily tire make. Certainly weight distribution couldn’t be that different from side to side with tanks basically empty. If anything, the passenger side should be heavier. But a check is certainly in order. How bout wheel bearing overheating leading to a hot tire?? Since the tread where looked ok, doesn’t seem like it’s wheel alignment.
I just came back from my tire dealer and would like to comment on my posts. First, yes the original Marathons blew. Both were on the right side when they blew. The two Kumho's blew on the left side. After looking at both tires very carefully my dealer thought I had hit something with the first Kumho that blew. He said his opinion was based on the fact that the sidewall was torn at a 90 degree angle to the wheel. He owned a tire recapping business for 30 years so I suspect his opinion is probably valid. I do not remember hitting anything in the road. On the second tire he could not find anything to cause the blowout. I think his opinion was probably good - he had nothing to loose because both were covered by total insurance. He replaced both of them. As a side note, he would not mount the new tires on two spare aluminum wheels I had. (Both original wheels were destroyed by the blowouts.) The wheels were almost new but were stamped with a maximum of 60 psi. The Kumho's are supposed to carry 65 psi. Lets hope that this is not a trend with the Kumho's! Be safe out there! My apologies for panicking everyone.