Enter the Society of Automotive Engineers and détente: Five of the six truck manufacturers mentioned above have agreed to assess their trucks' tow rating based on SAE standard J2807. The new standard lays out several benchmark tests for pickups, so automakers won't be allowed to simply find the right conditions and produce the highest tow rating possible anymore. For the J2807 test, a standardized trailer is hooked up and the truck is put through acceleration tests on level ground and an incline, and its response to effects like understeer, trailer-sway and braking are measured. Only Ford, General Motors, Toyota, Honda and Chrysler will be employing J2807 now, but by 2013 all pickup truck makers will be obliged to adhere to it.
Someone had to go first, and today we learn that Toyota has adjusted its pickup's tow rating to the new standard, and so the Tundra can tow less on paper today despite not a single change being made to the vehicle. Its towing capacities were lowered anywhere from 400 pounds on the 2WD regular cab (10,800 to 10,400) all the way up to 1,100 pounds on the 4WD CrewMax (10,100 to 9,000).
This shouldn't be viewed as a knock against the Tundra, because we won't know where it really falls until we get revised ratings from each of the other five manufacturers, and we expect them all to shift downwards.