D.O.T does mean something more then just if your going to drive on the street. In order to be D.O.T approved you have to meet stringent specs and requirements that a non D.O.T tire would not go through. A D.O.T tire in theory would have a better quality control, as a non D.O.T tire will not have to meet or be tested by those standards.
Its like racing seat belts. All the major racing brands are SFI certified, and they have to meet stringent testing requirements. Every racing series requires that your seat belts are SFI certified in order to race. Then you have brands like ProArmor and and several others that are not SFI certified. Sure they do the same thing, and in any non racing sanctioned event, should work just fine, but the fact is they could be made of cheaper Chinese webbing, maybe cast steal latches & buckles, vs the forged that is required to be SFI. You lose the Quality Control and responsibility when you are not certified or required to meet a standard.
Anytime you are following a spec or are certificated you are going to be held to a higher standard, and 9 out or 10 times you will find a better more consistent made product by those companies.
