A higher load range is gonna cost more but would last longer, as the running surface of the tire is thicker.
Have you looked at the tread on the inner and outer edges and are they worn even or have shoulder issues like flat spots or "river wear" thats the most common issue but is generally followed by a pulling left or right, only why to fight that is tire rotation,The shaking is most always from belts broken.
I would start by looking for a tire dealer like bandag, best one tire, or a tire dealer who specializes in semi tires who can install and balance I would not use a truck stop garage like petro or loves.
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