I put mine on the scales at the Air National Guard base that I used to drill at. The scales are used to weigh vehicles and pallets of equipment. My truck weighed in at 6060 lbs. That was with me in it and I can't remember if I was at a half a tank or full tank of gas. I weigh about 160 to 165. So that puts it around 5900 lbs. I have a 04 FX4 Scab Flareside 4x4

 

Remember, a full tank of 87 weighs 184.68 pounds. (Based on 27 gallons). The density of gasoline also goes up and down with temperature, therefore changing the weight (a VERY small bit).
MK

 

Gas is 6lbs per gallon, Lariat Screw @ 30 gallons = 180lbs

 

Yep I forgot about the weight of the gas.

 

Gasoline (87) is 6.889 pounds per gallon.
MK

 

Actually it varies from 6.216lbs for regular unleaded with a gravity weight of 58 to 6.35lbs per gal for premium with a gravity weight of 54. These would be higher with a maximum limit of 10% ethanol.