What Is the 80% Towing Rule? A Complete Guide for Safe Trailer Towing

The 80% towing rule serves as a generally accepted recommendation for safe towing. It implies that the total weight of your loaded trailer should never exceed 80% of your vehicle's highest permissible towing capacity. To illustrate, if a vehicle's towing limit is 5, 000 lb, a trailer weighing less than or equal to 4, 000 lb would ideally adhere to this rule.

Nevertheless, the 80% figure should not be treated as legal or binding in the sense of being applicable everywhere. Instead, it's more on the side of a safety suggestion or common practice in the industry. For instance, what one jurisdiction might interpret as 80%, another could interpret differently. That being said, it's still a good rule of thumb if not a legal requirement.

You have a duty to comply with all laws relating to towing your vehicle, such as hitch rating, manufacturer's towing capabilities, trailer, payload of towing device, and local regulation, if any.

Answered FAQs: 80% Towing Guide Line

What is the rule of 80% towing?

This rule proposes not to exceed a maximum trailer weight of 80% in relation to the vehicle manufacturer-specified towing limit. It allows a bit of a buffer between real and the maximum weight, which gives a safer margin.

Is using 80% as the basis for towing something a law?

No, generally. Although 80% guideline may sound like a recommendation one should follow to the letter, it has to do with safety aspects rather than being a legal requirement. It is more likely to happen when different jurisdictions have different standards.

How is 80% of towing capacity determined?

Simply multiply the vehicle's maximum towing rating by 0.80.

Example calculation:

5, 000 lb maximum towing capacity × 0.80 = 4, 000 lb maximum towing weight

In this situation, you would consider the 80% guideline has been met if your vehicle could tow 5,000 lb and your trailer weighs no more than 4,000 lb when fully loaded.

Does trailer weight comprise cargo?

Definitely yes. It is best to use the real loaded trailer weight when making the decision whether or not a vehicle can handle the towing. You should not just consider the weight of the trailer itself or its advertised weight when you calculate the trailer weight. Items like, for example, fluids, equipment, cargo, and so on, will significantly make a trailer heavier.

How does the 80% towing rule function?

First, this is a very simple idea with some basic numbers.

Taking an example, a 6,000-pound manufacturer stated the trailer max towing capacity vehicle for an SUV, and assuming that the vehicle owner follows the 80% rule.

The formula: 6,000 × 0.80 = 4,800

In this case, the 80% rule means not to tow a fully loaded trailer with more than about 4.8 tons. This remaining 1.2 tons is considered as a safety margin, taking into account the variety of circumstances during towing, such as:

• Rises with steep gradients
• Windy weather
• Cars are stuck together in heavy traffic
• A jolt trailer
• An extra cargo
• Additional weight of passengers in the towing vehicle
• Weather, whether hot or cold
• A lengthy road journey

This is just a rough calculation. It does not actually make the maximum towing capacity higher of your vehicle. A vehicle is officially certified at 6, 000-lb towing capacity and will never have higher than that officially.

Why Is the 80% Towing Rule Being Adopted by Many?

Ripping away the road at the exact capacity with the trailer you are dragging can cause more stress to your car and the components.

The trailer modifies a lot of car operation areas, including:

Acceleration

The car must do the work for both the car and the trailer. The more heavier is the car and trailer, the higher is the workload on the car motor.

Braking

Braking time increases as speed or weight increases. To avoid any problems with the car and trailer both, the car and trailer brakes have to be maintained well, and the trailer should also be equipped and maintained with the proper trailer brakes.

Handling

A large or heavy trailer can greatly affect the car's steering and car steadiness in situations of an emergency.

The wind

A travel trailer or a tall trailer or an enclosed freight trailer can cause a lot of wind resistance.

The trailer sways in one direction and then stops.

Different reasons can cause a trailer swaying such as not balanced loading, inadequate tongue weight, crosswinds and many others.

Therefore, the 80% rule is a cautious planning method, but it should not be substituted for car and trailer manufacturer recommendations.

Example: Determining the 80% Rule

Let us assume that the maximum towing weight for a pickup truck is 7,500 lb.

Determine 7,500 × 0.80 = 6,000 lb.

To be under the 80% rule, a driver would probably want the weight of the trailer with everything in it to be around 6,000 lb or even less.

In addition to that, the actual weight of the trailer has to be taken into account as a major fact.

Let us suppose that the trailer has:

• Weight of trailer only: 4,800 lb
• Camping Equipment: 500 lb
• Water and other supplies: 400 lb
• Other stuff: 400 lb

In total:

4, 800 (weight) + 500 camping stuff + 400 water / food + 400 stuff = 6, 100 lb

With regard to trailer weight, it is 6, 100 lb, that would be heavier than the 6, 000-lb recommended under the 80% towing capacity rule, even though the empty weight of the trailer was way below the maximum allowable weight.

80% towing rule vs. manufacturer's towing capacity

This is the key point of difference.

If your vehicle is allowed to haul a maximum trailer weight of 5, 000 lbs according to the owner's manual, it is wrong to assume that the 80% rule changes this legally or mechanically to a lower towing capacity of 4, 000 lbs.

Actually:

• 5, 000 lbs is the maximum trailer weight a manufacturer declares under normal circumstances.
• the 4, 000 lbs is a 80% loading advisory only.

Follow the vehicle's manufacturer instructions and laws first and foremost.

Do You Need More Towing Ratings Checked?

The fact is, 80% calculation is not sufficient by itself.

1. Gross Vehicle Weight Rating (GWVR)

The vehicle and its contents, including passengers and cargo, together must not exceed the GVWR, which is the total weight of the fully loaded vehicle.

Beyond the normal load of the vehicle, adding of passengers and heavy equipment also limits the capacity left for trailer load, primarily tongue weight.

2. Gross Combined Weight Rating (GCWR)

GCWR means the combined maximum allowable weight of both the towing vehicle and trailer, but under what is specified or allowed by the manufacturer.

 

3. Tongue Weight

Tongue weight refers to the pressure exerted downward from the trailer on the vehicle's hitch.

A trailer should be loaded not only in a way that the tongue weight is just right but also in a way that the trailer can tow safely. It would be better to follow the trailer and vehicle manufacturer's instructions than just go by one number.

4. Hitch Rating

A correct-sized hitch capable of handling the trailer and its load is essential.

Sometimes the vehicle's towing limit is quite high while the hitch installed is rated much lower.

5. Trailer Brakes

If the trailer weight and the rule apply, trailer brakes are mandatory. Even where the law does not enforce trailer brakes, it is still very wise to have the appropriate braking equipment installed.

Local Towing Examples

In many simple situations on a daily basis, the 80% limit can also be used.

Ontario Travel Trailer Example

To enjoy a weekend in nature, a family decided to buy a travel trailer, which they can take to different spots around their home province of Ontario.

All they know is the car they have, the 5,000 lb SUV, can take the towing weight on top of what it's meant for.

Multiplying 80 percent, a guide:

5,000 × 0.80 = 4,000 lb

The family must know for sure what they are doing to be safe by checking out the trailer's loaded weight; that's the water, camping gear, food, their clothing, luggage, and such things as the supplies.

Also, the capacity of the vehicle, hitch rating, and the laws applicable in Ontario should be the main references for the family.

Alberta Boat Trailer Example

A person who enjoys the outdoors and water sports in Alberta is planning on spending a weekend away on a lake trip.

The boat's advertised weight without any items in it, dry weight, should not be the sole consideration that determines how much the trailer can actually be loaded. Instead, one should account for:

• Boat
• Trailer
• Fuel
• Battery
• Safety gear
• Fishing gear
• Personal items

That would result in the trailer+boat system's total loading being compared to the limits provided by the manufacturer of the car and the safety margin that the driver would like.

Toronto Utility Trailer Example

The towing of a utility trailer in Toronto might be assumed initially by someone that it is only a light trailer.

But, as a matter of fact, building supplies as well as different types of tools and machinery can increase the total weight of the trailer significantly.

How to Determine Your Truck's Towing Capacity Before You Go Camping

This is the checklist to go through before hitching a trailer to your car.

Step 1: Check the Owner's Manual

Check the manufacturer's tow specifications for your exact vehicle configuration, including any optional features that may affect tow capability.

Step 2: Determine Trailer Weight

Find the weight of the trailer you are hitching up using manufacturer specifications, and if possible, weigh the loaded trailer.

Step 3: 80% Rule

To get the number, you can safely hitch up to multiply your car/vehicle's maximum towing limit, as given by the manufacturer, by 0.80 or 80%.

Step 4: Calculate Your Payload

Think of the weight of your passengers/crew plus your luggage, the stuff you have loaded on it that you normally use or carry with you, and the trailer's hitch or tongue weight. Everything is included.

Step 5: Verify Hitch and Equipment Ratings

Check that the hitch, ball mount (hitch carrier or coupler), safety chains, and towing equipment meet the necessary requirements/ratings.

Step 6: Trailer Brakes and Tires Inspection

Do a thorough inspection of the trailer tires, rims/wheels, brake system, and lighting before making the trip/setting off.

Step 7: Balance/Spread Weight on the Trailer

According to the trailer factory's guidance, put the stuff inside (cargoload) and keep the balance so no part of the trailer is too heavy, e.g., do not make the tail/rear end of a trailer overweighed.

When to Contact Professional Towing Services?

Apart from the usual cases you should not attempt on yourself, such as towing a damaged/damaged trailer, an overloaded trailer, or a trailer in any way it is unsafe to tow or difficult to tow. These may lead you to face extra risks besides getting yourself or others hurt.

In the case that either your vehicle or the trailer has had a breakdown/damage during the towing situation, there's a collision/accident or whatever the cause is, it has been that both have somehow gotten together and there is a problem and that you need equipment for recovery/transport; calling upon the assistance of a professional towing service can prove to be the right option for dealing with the problem.

• Your car breaks down while you are driving with a trailer
• The trailer is having a damaged wheel/axle
• You have been involved in an accident
• The trailer is not moving, as it got stuck somehow
• A loaded trailer can't be safely removed/moved
• You are in need of getting recovery or transport equipment

A towing company of the higher level will be equipped with all the necessary knowledge to assess and find out what kind of tow truck is to be considered after examining the problem scenario and also decide what kind of recovery equipment will be needed.