Why does my truck shake at 60 mph?

What is your question?

While driving down the road, once i get to about 58 mph my truck will start shaking. It increasingly gets worse up until about 70 mpg it dies down. Around 62- 63 is definitley the worse. I just got brand new tires, replaced the pitman and idler arm, its been alligned, i dont know what else to do with it.