This is not entirely true....ALL LOAD RANGE 'D' and ALL LOAD RANGE 'E' tires, well actually all tires produced to be sold in the USA, must conform to a government regulation standard for loads and inflations know as THE TIRE AND RIM ASSOCIATION OF AMERICA. This publication is used by all tire manufactures to designate load and max inflation pressures (on P-metric and LT-metric tires). Recently, some tire manufactures have begin to fudge the inflation pressures in order to try and increase the load. If this happens they must add additional engraving on the sidewalls to account for the fact that this information is not EXACTLY what is published in the book. Some of the wording may be something like "CANADA USA CODES ONLY" or the like. I can tell you that even if the load rating of a oversized 'D' tire is equal or close to the 'E' rated tire, and you are involved in an accident, you had better have a dang good attorney or you MAY be found at fault. It happens time and time again, and now that the US government is involved and the NHTSA organization is involved, and after the FORD/Brigestone attention, the courts look for tire related information in almost every case. If the placard says 'E', and it does.... then I would highly recommend 'E' as replacements.

As for construction of tires being different from manufacturer to manufacturer...this is true, but they all are tested under the exact same methods and standards required by the government. Some perform better than others, but do you really think for a minute that any manufacturer of any goods are going to provide an exceptionally better product at their cost? It is never gonna happen. There is only a limited number of raw material suppliers in the world for components that go into tires, and Goodyear owns most of them, so all tire manufactures around the world use the same basic components however some use different compounds to achieve the testing results. Bottom line is you will get different wear, different sidewall stiffness, different ride quality, etc...from different manufactured tires, but if you notice there is no wear rating (also known as UTQG..Treadwear,Traction, Temperature) on LOAD RANGE C,D,E tires....there is pretty much no treadlife guarantee for light truck tires because they are used, or misused, in such a wide variety of applications.

Clear as mud...right!