What Percentage Should a Boat Trailer’s Tongue Weight Be?

The tongue weight should be about 5–10% of the combined loaded weight of the boat, motor, trailer, fuel, and gear. Keeping tongue weight in this range helps prevent trailer sway and ensures stable, predictable towing; many manufacturers land near 7–10% for most boat trailers.

Why Tongue Weight Matters

Tongue weight is the downward force the trailer exerts on the hitch. If it’s too light, the trailer is prone to sway; if it’s too heavy, steering and braking can degrade, and you can overload the rear axle or hitch. Boat trailers often target a slightly lower percentage than general cargo trailers because boats concentrate weight aft and sit lower in the bunks or rollers, affecting balance.

How to Measure and Calculate Tongue Weight

You can estimate tongue weight using a simple calculation and then verify it with a scale to be sure you’re within the 5–10% window.

1. Determine the loaded trailer weight (also called gross trailer weight): include the trailer, boat, motor, fuel, batteries, water, and all gear.
2. Calculate the target tongue weight: 5–10% of the loaded trailer weight (for example, a 3,500 lb loaded boat and trailer should have 175–350 lb on the tongue).
3. Measure tongue weight: use a tongue-weight scale, a vehicle scale (subtracting axle readings), or a heavy-duty bathroom scale and lever method for lighter rigs.
4. Compare the measured result to your target range and to the tow vehicle’s and hitch’s tongue-weight ratings. Never exceed component ratings.

Confirming your actual tongue weight, not just estimating, is important because added fuel, coolers, and fishing or diving gear can shift balance and push you out of the safe range.

Symptoms of Incorrect Tongue Weight

Recognizing the handling clues can help you catch issues before they become hazards on the road.

• Too little tongue weight (under ~5%): trailer sway at highway speeds, “wagging” in crosswinds or when passed by trucks, and a light, wandering feel at the steering wheel.
• Too much tongue weight (over ~10%+ for many boat trailers): front-end lift on the tow vehicle, longer braking distances, bottoming-out over bumps, and headlight “aim-up.”
• Uneven load distribution: one axle carrying more load than the other on tandem trailers, or tires running hotter on a single side.

If you notice any of these, re-weigh and adjust your load before continuing, rather than trying to “drive through” the problem.

How to Adjust Tongue Weight Safely

Small changes in where the boat and cargo sit can have outsized effects on balance. Make adjustments incrementally and recheck.

1. Shift the boat on the trailer: move the winch post or bow stop slightly forward or aft to increase or decrease tongue weight.
2. Reposition gear: stow anchors, fuel, ice chests, and tools to fine-tune balance—heavier items placed forward increase tongue weight.
3. Check axle placement and bunk/roller setup: on some trailers, an axle assembly can be moved to correct persistent imbalance (have a qualified shop perform this).
4. Verify hitch height: keep the trailer level when hitched; a nose-high trailer can reduce effective tongue weight and promote sway.
5. Consider equipment compatibility: if you use surge brakes, verify that any weight-distribution or sway-control device is compatible and approved.

Always re-measure tongue weight after changes, and ensure you remain within the trailer, hitch, and tow-vehicle ratings for both tongue and gross weight.

Expert and Manufacturer Guidance

Marine safety organizations and trailer manufacturers commonly recommend maintaining 5–10% tongue weight for boat trailers, with many setups performing best near the 7–10% range. Some general towing guides cite 10–15% for conventional cargo trailers; for boats, follow your trailer and boat maker’s specific recommendations, which typically land lower due to hull geometry and weight distribution. When in doubt, consult the trailer’s compliance label and the tow vehicle’s owner’s manual for exact limits.

Key Takeaways

Plan for 5–10% tongue weight of the loaded boat-and-trailer combination, verify it on a scale, adjust the boat position and cargo placement as needed, and respect all component ratings. Stable towing starts with correct balance.

Summary

The tongue weight of a boat trailer should be maintained at about 5–10% of the total loaded weight of the trailer, boat, motor, fuel, and gear—often best around 7–10%. Measure it, adjust load placement to stay within range, and ensure compatibility with your towing setup to reduce sway, preserve braking and steering, and tow safely.

What percentage of trailer weight should be on the tongue?

For a standard trailer towed with a bumper-pull hitch, the tongue weight should be between 10% and 15% of the total loaded trailer weight (Gross Trailer Weight or GTW) for safe and stable towing. A lower tongue weight risks trailer sway, while a higher weight can make the tow vehicle difficult to steer. Gooseneck trailers, which use a different hitch system, typically require a higher pin weight, often 15% to 30% of the loaded trailer’s weight. 
Why is proper tongue weight important?

• Trailer sway: Too little tongue weight shifts cargo behind the trailer’s axle, leading to a dangerous side-to-side fishtailing motion. 
• Control: Proper tongue weight creates a balanced line between the tow vehicle and trailer, improving steering response and braking. 
• Tire wear: Excessive tongue weight can overload the rear tires of the towing vehicle, affecting steering and control. 

How to determine the right tongue weight:

1. Calculate your GTW: Add the weight of your empty trailer to the weight of all your cargo. 
2. Apply the percentage: Multiply your GTW by 0.10 (for 10%) and 0.15 (for 15%) to find the ideal tongue weight range. 
3. Adjust your load: Position 60% of your load in front of the trailer axles and 40% behind to help achieve the target tongue weight. 
4. Measure it: Use a dedicated tongue weight scale or a hitch with a built-in gauge to accurately measure the force on the hitch ball or pin. 

Important considerations: 

• Check your manuals: Opens in new tabAlways consult the specific manuals for your vehicle and trailer, as they may provide detailed recommendations for tongue weight.
• Measure before each trip: Opens in new tabVerify your tongue weight before every trip, especially if you are carrying different cargo.

What percentage of the total weight of the boat motor trailer and gear should the tongue weight of a trailer be?

7 percent to 12 percent
Tongue weight is exactly what it says: the weight of the trailer tongue on the hitch of the tow vehicle. The rule of thumb is that you want a tongue weight equal to 7 percent to 12 percent of the total weight of the (fully loaded with fuel and gear) boat/motor/trailer combo.

How much tongue weight should be on a boat trailer?

Boat trailer tongue weight is the downward pressure the loaded trailer exerts on the tow vehicle’s hitch, and it should generally be between 5-10% of the trailer’s total weight for a stable tow. Too little weight can cause the trailer to sway, while too much can make the tow vehicle difficult to steer. You can measure it at a commercial truck scale by weighing the truck and trailer together, then the truck alone, to find the difference, or at home using a bathroom scale with a lever system. Adjust tongue weight by moving the boat and its contents forward to increase weight or backward to decrease it.
 
This video explains how to measure and adjust trailer tongue weight: 59sNKP GarageYouTube · Mar 25, 2022
Why Proper Tongue Weight is Important

• Stability: Proper tongue weight is crucial for a stable and safe towing experience. 
• Swaying: Too little tongue weight can lead to trailer sway and loss of control. 
• Steering: Too much tongue weight can make the tow vehicle difficult to steer and can overload the tow vehicle’s suspension. 
• Fuel Efficiency: Correct tongue weight can also contribute to better tow vehicle fuel efficiency. 

How to Determine the Correct Tongue Weight

1. Calculate Total Weight: Opens in new tabDetermine the total weight of the trailer, boat, fuel, batteries, and any other cargo. 
2. Calculate Target Tongue Weight: Opens in new tabMultiply the total weight by your target percentage (5-10%). For example, a 5,000-pound trailer requires 250-500 pounds of tongue weight. 

How to Measure Tongue Weight

• Commercial Truck Scale (Easy Method):
  1. Pull the tow vehicle and trailer onto the scale, with the trailer’s wheels on the scale. 
  2. Get the weight reading. 
  3. Drive the truck off the scale, disconnect the trailer, and drive the truck back onto the scale alone. 
  4. The difference between the two weights is your tongue weight. 
• Bathroom Scale (At-Home Method):
  1. Park the trailer on a level surface. 
  2. Use a sturdy block of wood and a bathroom scale under the trailer tongue. 
  3. Position a block or brick on the ground, and the bathroom scale on a piece of plywood on the ground. 
  4. Position a 2×4 across the pipes to leverage the tongue weight onto the scale and block. 
  5. To find the actual tongue weight, you may need to multiply the scale’s reading by a factor (e.g., 3 or 4), depending on how far the scale is from the tongue and the block. 

This video demonstrates how to adjust the tongue weight using a bathroom scale: 51sSmall Sailboat CruisingYouTube · Jun 26, 2022
How to Adjust Tongue Weight

• To Increase Tongue Weight: Move the boat, its contents, and the winch post forward. 
• To Decrease Tongue Weight: Move the boat, its contents, and the winch post backward. 
• Tandem Axle Trailers: May have a greater margin for error and might accept less tongue weight (around 5-8%). 

Where should 60% of the weight in a trailer be distributed?

The simple rule to follow is to place 60% of the weight in front of the axle and 40% behind. It doesn’t matter if you’re loading a single-axle, double-axle or triple-axle trailer, the 60/40 rule still applies. An unbalanced trailer can lead to trailer sway and other dangers while driving.