Imagine driving down the road on a vehicle with egg shaped tires. It would be pretty hard to control the vehicle or to drive safely. That's the kind of wobbly, out-of-control situation you might find yourself in if you try to tow a trailer with improper tongue weight.
Proper Tongue Weight
If you don't have enough weight on the trailer tongue, less than 10 percent of the total loaded trailer weight, the trailer can end up swaying from side to side, making it difficult to control. If you have too much weight on the trailer tongue, more than 15 percent of the total loaded trailer weight, it can overload the rear tires and push the rear of the vehicle around. You might not be able to go around corners and curves properly, and your vehicle might not stop fast enough when you press the brake pedal.
Start with a correctly placed load to end up with the proper tongue weight and a safe trailer towing experience. The tongue weight is the static force the trailer tongue exerts on the hitch ball. An improper load condition can make for a dangerous trailering situation. Proper trailer tongue weight can make the difference between a safe trailer towing experience and a difficult journey.
According to the 2013 GMC Trailering Guide, to get the proper trailer tongue weight, you should put about 60 percent of the load centered evenly over the front half of the trailer. You can calculate the proper trailer tongue weight by figuring 10 to 15% of the total loaded trailer weight. For example, a 3,000 pound trailer has a proper tongue weight of 300 to 450 pounds.
Check and Balance
Weigh your combination at a public scale positioning the rig so you know the weight on the tow vehicle tires separately from the trailer tires. Disconnect the trailer and weigh the tow vehicle only. Subtract the tow vehicle weight from the combination total to get your trailer weight and subtract the tow vehicle solo weight from the tow vehicle portion of the combination weight to get your tongue weight. If you need to increase tongue weight, move the load forward a bit. If you need to lighten tongue weight, move the load back a little.