Bills Mobile Hitch & Tow Bar Installation


What Is Supplemental Braking System And Where Can It Be Used?

If you think that hitch installation and lighting are all there is to connecting your RV and towed vehicle, you need to think again. There’s much that you still need to be aware of. One such factor is setting up the braking system in your towed vehicle.

Addressing the brake issue in your RV is a concern among many RV owners. In fact, many states in the US don’t even allow an RV without braking systems installed. If you are one of those who are not yet aware of the need for a towed vehicle braking system, then let us help you out. This blog will cover all there is to know about these braking systems and why you should get one for your towed vehicle. 

But, before we move on to why you would need the braking system, let us familiarize you with what the brakes are and how they work. 

Let’s get started!

What Is Supplemental Braking System And Where Is It Used? 

A supplemental braking system is a system that allows the towing vehicle to have brakes with its unique working mechanism. It is a safe system that provides various benefits, such as better vehicle control while reducing the wear and tear the RV goes through.

These systems for brakes may seem different, but the core concept is the same as the regular brakes, which is to apply brakes on an RV. There are also several words that refer to a towed vehicle, such as toad vehicle (as towed as toad are similar in pronunciation), dinghy, etc.   

Why Do You Need A Supplemental Braking System? 

People install supplemental braking systems on their RVs for many reasons. Below is a list of all the major ones.


This may be the most common reason to get a supplemental braking system, but it is also one of the most important reasons. The braking system acts as a helping hand for your RV, providing you with a safe towing experience. You also get better control over the toad vehicle, eliminating the risk of carrying tons of weight at the rear. 

Tow Bars That Last Long With Improved Functionality

One of the reasons that lead to failure in towing systems is the sudden stops without a supplemental brake. It is where the supplemental braking system comes in and helps by providing added functionality to the toad vehicle. The force exerted on the tow bar also gets limited by using a supplemental brake system, leading to longer life of the Tow Bar. 

It also helps reduce the stopping distance, preventing possible accidents due to the high braking distance. 

Reduction In Stress Of The Vehicles

Whether it is your motor home or the toad vehicle, the stress that is put on them gets significantly reduced with the installation of a supplemental braking system. Usually, motor homes are not designed to carry excess weight. The absence of a braking system leads to high stress due to the excess weight behind it. 

The braking system also allows for lowering the stress on the wheels and tires of the towed vehicle. It is because of the reliance of towed vehicles on the motor home without the supplemental braking system. 

Supplemental Braking System Law 

You should know that almost every state in the United States requires the installation of supplemental brakes on their toad vehicles by law. The requirement is for the supplemental braking system installation in vehicles that exceed a certain amount of weight while towing. The laws vary in different states, automatically leading to a variation in required weight. 

Getting a supplemental braking system is always a good idea, no matter the reason. So, even if there is some leeway in the law for the requirement, you should still go for its installation.  

Types Of Supplemental Braking Systems And Their Features 

Broadly, there are four types of braking systems that are used in Toad vehicles. These are pre-set systems, proportional systems, direct systems, and vacuum assist systems. These can be put into two categories: portable and non-portable. 

Before moving on to the types, let’s try to understand the categories of these braking systems, which are less complicated than their types.  


These braking systems are just as they are called, portable. They are removable and have their own advantages over the non-portable ones. A portable braking system is good for 

  • RV users have a tendency to change their tow vehicles in a span of years.
  • People who own multiple vehicles for towing
  • Anyone who is not sure about keeping the towed vehicle they currently use.
  • Those who are looking for a cheaper option. 

These may be cheaper options, but there are some cons of using them as well. It would make it very busy for you as you will have to keep setting it up every time you go out with your vehicle. The process may not be complicated, but it translates to extra work for every use of the towing vehicle. Ultimately, it is only more time and effort, even if it may be minimal. 

Another con for a portable braking system is the storage issue every time you unload it, especially when you are out. All of this only leads to additional hassle for you if you choose to get a portable system. 


It is the second category of supplemental braking systems, where once the installation of the braking system is complete, it can not be undone. That is why it is a permanent type of braking system. 

There are several benefits of a permanent one, such as 

  • Saves you the time and hassle of installing the system every time. This function is very useful for those who want to keep a towing vehicle for a long time. 
  • It will also save the storage space that you may have needed otherwise if you had gone for a portable one. 
  • The cost of installation is a one-time cost. There would be no future costs.

Just like the portable braking system, there are cons of a non-portable one as well. While the installation is only a one-time process, the cost and skill required for the installation are significantly higher. It would be a good idea to go for a professional installation service.

There are pros and cons to both categories of braking systems. You need to use your own discretion in making the choice. Now let’s move on to the mechanical divisions of these braking systems, which we already mentioned above. 

Pre-set System

It is the most basic type of supplemental braking system. This system falls in the category of portable braking system. The setting up of this system is also very easy, and since it is portable, you can use it with many vehicles. It comes with breakaway mode, which applies brakes to the towing vehicle in case the RV and the towing vehicle get detached. The application of brakes is through the signals sent by the electric brake controller. 

Proportional System 

The proportional braking system is one of the most popular braking systems in towing vehicles. This system is installed on the driver’s floorboard of the toad vehicle. It applies the brakes to the dinghy using the RV’s inertia. It basically means that the system brakes the vehicle in proportion to the brake in the RV. The proportionality of the brake is a convenient feature that allows greater control of the dinghy. 

Direct System

Direct systems of braking are more complicated than the other systems in terms of installation. However, it also allows them to provide much better control than the rest. There is no need for manual adjustment, and the response time is also much better. The direct braking system is physically connected to the brake lines of the tow vehicle. 

This type of braking system is also more expensive and would require a professional to install. The physical connection between the brakes lets it replicate the timing and pressure of the vehicle’s brake leading to higher accuracy in the brake timing. 

Vacuum-Assist System

A vacuum-assist system is a type of supplemental braking system which provides power brakes to the tow vehicle. It is also known as an active system and can either be direct or proportional. The power brakes can come from either the motorhome’s vacuum or its own vacuum. 

The system creates the experience of brake application which is the same as the driver braking the dinghy directly. This option is also the best for vehicles having power assist brakes. It is because the other systems can cause damage to the braking system. 

This system was developed in order to make the braking experience of the driver easier. You need to use a higher force to apply the brake properly in the absence of a vacuum assist braking system. Thus, making it a convenient option. 

When a vehicle is turned off, the power assist function does not usually work. It can even lead to unnecessary damage to the brake and its components because of the need for extra force for effective braking. However, the vacuum assist type of supplemental braking system has a different story to tell. 

Also read: How does a weight distribution hitch work and how to set up it

Pros & Cons  

There are several advantages and disadvantages of supplemental braking systems. However, these are not general and vary depending on the type of system. This section will list the pros and cons of each type of supplemental braking system. 

Pre-Set System 


  • Easy Installation
  • Switch easily between different vehicles with its portable design
  • Breakaway mode, which adds more convenience


  • Since the system is non-proportional, it does not offer complete emergency brake
  • Limited adjustment restricting the accuracy and control of the vehicle
  • Pre-set braking system only works with dead pedals**

**A dead pedal means that there is no power in the toad brake while towing

Proportional System


  • Synchronization between the toad and the towing vehicle’s braking systems
  • Adjust the pressure manually to avoid excess braking
  • Easy installation
  • The design is portable, allowing easy switching between different vehicles. 


  • It only works with dead pedals, not other vehicles or hybrids

Other cons are similar to the cons in the pre-set braking system.

Direct System


  • The intensity and timing of the braking are well synchronized, which allows much better control than other braking systems. 
  • There is no need for adjustments. 
  • There is rarely the need to reposition the actuator.


  • Difficulty in installation due to a complex mechanism. 

Vacuum Assist System


  • Toad brakes remain safe from damage due to excessive pressure in the braking system. 
  • Compatible with vehicles having power assist systems and hybrids
  • Least wear and tear of the toad braking system


  • Installation is difficult 
  • Non-portable braking system which restricts switching between different vehicles

How Does A Supplemental Braking System Work?

The working of supplemental braking systems also varies with the different types of systems. Let’s understand how each type of supplemental braking system work. 

Pre-Set System

The braking system is connected to the RV with a wiring harness**. When the brake lights of the RV are engaged, the system activates. Once it is activated, the actuator starts mounting in the toad vehicle. The arm extension then depresses the brake pedal after the signal and activates the brakes. The illumination of the indicator light in the motor home is the signal for the activation of the brake. 

**A wiring harness is an arrangement of cable or electrical wires which are responsible for the transmission of electrical signals. 

Proportional System

The proportional braking system contains sensors that respond to the tow vehicle’s braking. These sensors work on the inertia of the towing vehicle and quickly adjust to the change in their brakes. Its actuator then starts mounting in the toad vehicle as the arm extension depresses the brake pedal. Now, the monitor mounts the motor home inside and provides in-depth information on the braking of the toad vehicle. 

Direct System

The way a direct system works is by connecting the tow vehicles’ brake line with the actuator. This is how the brake activates after the indicator light mounts the motor home. 

Vacuum Assist System

Unlike the other supplemental braking system types, the vacuum assist system uses the vacuum source of the RV. This source activates the vacuum to assist in the bakes of the toad vehicle. The system then connects to the RV with a wiring harness and sends signals to the actuator. The toad vehicle’s brakes depress after getting the signal, lighting up the brake lights of the RV and activating the brakes.

What Type Of Supplemental Braking System To Opt for? 

Now that you have a good understanding of the advantages, disadvantages, and functioning of a supplemental braking system and its various types. It’s time to understand whether you should go for a professional installation of the braking system or what any standard installation would do for you. 

If you are only concerned about adhering to the law of different states and nothing else, any braking system would be good enough for you. It would be best to go for a cheap one in such cases. 

However, there are various other reasons why people choose to go for a supplemental braking system. These can be as follows

  • Many people seldom tow cars, but they like to be prepared when they might need the braking system. Choosing a pocket-friendly supplemental braking system would work best in this case. 
  • For someone who is looking to drive on tough terrains and that too on a regular basis, then it would be a good idea to go for a durable brake. A proportional or direct braking system would do the job. 
  • A vacuum assist braking system is a great option for you if you are looking to go for a long trip. It is because of the dependability it offers in comparison to the others. You will also get a very smooth traveling experience. 
  • If you are someone who wants to install the supplemental braking system on their own, saving your bucks, then a pre-set system or a proportional system would be the right choice for you. 
  • For someone who has to work with heavy-duty towing vehicles, a direct system is the one to go for. It is because of its high responsiveness to the vehicle’s brakes. 
  • Wear and tear can also affect the choice of getting a supplemental braking system. If you also worry about that, the vacuum assist braking system should be your go-to choice. 

Best Supplemental Braking System Installation Service

While there are types of supplemental braking systems that are easy to install, the work of a professional would still give you a sense of relief and satisfaction. It is also a good option to save time, as not everyone may have the time or patience to go through that process. 

With Bills Mobile Hitch And Tow Bar Installation, quality product, and professional installation is only a call away. We provide the best quality supplemental braking systems and various other towing-related products with top-quality installation services that you can rely on. It has been several years since we have been in this industry, and it has got us customers who rely on us and trust us. We assure you that you will always leave with satisfaction and provide them with guarantees to show our affection. 

Contact us now, and we will be right there to help!

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