Actually auto Manufacturers speed limiters are based more on tire speed rating than anything else, and they have to find a happy medium between the load rating of the tires, the speed rating, ride comfort and noise (both tire and road) like 1fastbob states, the speed rating of the tires that ford supplies is "t" which is 113mph, the load index is 111 which is 2400lbs, more of one of these gets you less of another!