[OrrieG]

Look at this page, it gives the rear spring capacity (2900# total). Subtract the weight of the truck (1/2 distributed to the back) which is on the same page, or maybe another, then add back in passenger, fuel, motorcycle and accessories weight. Subtract from total and remainder will be the tongue weight you can tow using the stock springs and frame which was designed to match the spring capacity. Next question will be engine and drivetrain upgrades to pull the total weight of truck, cargo and trailer.