The maximum weight your vehicle axles are designed to carry. In other words, all weight supported by the axles, including the trailer tongue weight. This information may be found in the vehicle owner's manual. This is the weight of the trailer including the boat, and all the gear on the boat. This figure may be found on the trailer capacity plate.
Tongue weight is the weight of the fully loaded boat on the trailers' hitch, or tongue.
Having too much weight on the tongue can overly fatigue your tow vehicle, and make handling difficult. Having too little weight on the tongue can make the trailer fishtail as you are driving, and pull up on the rear bumper. For heavier boats, a commercial truck scale is your best bet. Class Gross Weight of Trailer and Load Class 1 Not to Exceed 2000 lbs. Class 4 Over 5000 lbs.