Chapter 12: Towing a Trailer

Towing a trailer transforms a vehicle’s handling, braking, and stability, introducing new risks that every driver must understand and manage. Knowing the specific laws and safe practices for towing in Montana is essential for passing the driver’s exam and, more importantly, for preventing dangerous situations like trailer sway or collisions caused by increased stopping distances. Mastering these skills ensures the safety of the driver, their cargo, and everyone else sharing the road.

Safely towing a non-commercial trailer involves using the correct equipment, loading the trailer properly, and adapting driving techniques to accommodate the added weight and length. Montana law specifies requirements for hitches, chains, lights, and brakes to ensure the entire rig is safe for highway use.

Equipment and Loading

Before a trailer is ever moved, it must be properly equipped and connected to the tow vehicle. The cargo must also be loaded in a way that ensures stability at all speeds.

• Hitch: The hitch is the critical connection point between the tow vehicle and the trailer. It must be rated for the gross weight of the trailer and its cargo. Using an underrated hitch can lead to catastrophic failure.
• Safety Chains: Two strong safety chains are legally required to connect the trailer to the tow vehicle. They act as a backup connection if the hitch fails. The chains must be crisscrossed under the trailer tongue (hitch) and attached securely to the tow vehicle’s frame. This crisscross pattern creates a “cradle” that can catch the trailer tongue and prevent it from digging into the pavement if it detaches.
• Lights: The trailer’s electrical system must be connected to the tow vehicle so that its lights work in sync. A trailer must have functioning taillights, brake lights, and turn signals that are visible from the rear.
• Brakes: In Montana, any trailer with a gross weight of 3,000 pounds or more must be equipped with its own braking system on all wheels. These trailers must also have a “break-away” system, which is a safety feature that automatically applies the trailer brakes if it completely separates from the tow vehicle.
• Proper Loading (60/40 Rule): The balance of the cargo is the single most important factor in preventing trailer sway. The majority of the weight must be placed in front of the trailer’s axle.
  • Follow the 60/40 rule: Place approximately 60% of the cargo’s weight in the front half of the trailer (ahead of the axle) and 40% in the rear half.
  • Heavier items should be loaded first, centered left-to-right, and placed over or slightly in front of the axle.
  • This loading method ensures proper tongue weight—the downward force the trailer tongue exerts on the hitch. Tongue weight should be about 10-15% of the total loaded trailer weight. Too little tongue weight is the primary cause of dangerous trailer sway.

Pro-Tip:
When attaching safety chains, crisscross them under the trailer tongue. If the hitch ever fails, the crossed chains will form a cradle to catch the tongue, preventing it from dropping to the pavement and causing a complete loss of control.