Editor's note: An earlier version of this story misstated when General Motors started subtracting the weight of some items on its pickups before calculating their maximum payloads. The company started doing that on its 2014 light-duty full-sized pickups. And it started subtracting items on its 2015 heavy duty pickups.
DETROIT -- How hard is it to weigh a pickup?
If the revelations from Ford Motor Co. and General Motors over the past week are any indication, it is difficult indeed.
At issue is how Ford and GM calculate the maximum payload for many profitable pickups -- and the companies' changing stories on their methods.
To come up with the figures, the two automakers acknowledge, they delete the weight of some heavy parts, such as the spare tire or rear bumper, from the base curb weights of many of their pickups.
The practice allows the companies to claim a maximum payload capacity that is higher than the rating for the pickup's base model -- one with no added or deleted factory options.
With the practice, some pickup owners could conclude they can carry heavier loads than they should.
"It's gamesmanship, with manufacturers trying to be the king of the hill," said Mitchell Dale, a Ford dealer in metropolitan Houston. "Quite frankly, it could drive a concern about confidence when they play games like this."
Pickup rivals Ram, Toyota and Nissan rely on standard base curb weights to establish their payload capacities, without subtractions.
In the cutthroat full-sized pickup segment, a higher payload rating can provide a marketing advantage. Heavy-duty pickups accounted for about a quarter of the 1.1 million full-sized pickups sold in the United States through July of this year, industry sources say. With average transaction prices above $50,000, huge amounts of revenue are on the line.