Adjusting your trailer brake gain can be one of those tasks that you feel you never get right. And to make things more confusing, it seems like everybody has a different theory on what the gain should be.
The thing to know with setting your trailer brake gain is that everyone has a different setup, and each situation is unique. Trailer load, tow vehicle, braking power, and trailer brake controller all vary from one rig setup to the next. So how can a rule thumb setting work for everyone? The real truth is that it can’t. To say to set your gain with a universal number and hope that it works for each rig is not possible.
However, there are some steps that we can go through that will help you set the trailer brake gain best for you. This post will cover those steps, including:
- Trailer Load
- Electric Trailer Brake
- 3 Steps to Adjust Your Trailer Brake Controller
Whether you tow a travel, utility, or boat trailer, these steps will apply and help you correctly set the gain when towing any trailer.
Table of Contents
Trailer Load
I remember the first time I had to adjust my trailer brake gain. The trailer dealer took me on the road and helped me set up the gain to where I was good a stop with no jerking. I thought I was set life! Once I loaded the trailer and my brakes wore down a little, that setting was useless, and I needed to adjust my trailer brake controller again. That’s when I realized that setting my trailer brake gain would be an ongoing task.
Your trailer load is the biggest factor in how you should set the trailer brake controller. So as we go through these steps, try to load your trailer to the typical weight. Your weight for travel and boat trailers is consistent, so this shouldn’t be a concern. This is more for utility trailers that may have a heavy trailer loaded with bricks one day and the other day just a sofa. Both extremes will need a different setting and adjustment to the trailer gain.
Electric Trailer Brake
Now that you have the trailer load to the typical weight let’s look at the electric trailer brakes. When your trailer has electric brakes, you need a brake controller to transfer that braking force. And unlike surge brakes or hydraulics brakes, electric brakes need that signal the electric brake controller to work.
Before we get on the road to adjust the gain, check that your brakes are working well and adjusted. Many trailers now have self-adjusting brakes. So check that the drum brakes move freely and that they work when you press the brake pedal.
One time I had my ground wire disconnected at the axle. I thought it was a setting on my brake controller, but there was no power to the brakes. This taught me the lesson of always ensuring all brakes work properly before heading out on the road.
Setting Trailer Brake Controller
Now that your trailer is loaded and the brakes adjusted and functioning properly let’s get ready to get on the road. As we discussed above, all rigs are different, and no one size fits all when it comes to setting your gain. So the best way is to get on the road and follow these three steps for your gain adjustment.
Step 1: Adjust at a slow speed
Find a side street or residential street where you can stop and go slowly without any issues. Go about 25 MPH. Lightly press on the brake pedal. At this slow speed, with just the slightest tap of the brake pedal on your truck brake, you should feel the trailer brakes working and holding you back a little. If you don’t feel the trailer slowing down and the truck takes longer than usual to stop, then your gain needs to be adjusted.
Also, you want the gain adjustment where this is not jerking you back, either. Too much, and you come to a rough stop. You should come to a normal stop with a slight feeling that your trailer is slowing you down.
Step 2: Adjust at a higher speed
Since the trailer brakes are working and tested at a slower speed, it should be safe to take them at higher speeds to see how it feels. I would say try on a road that is around 45 MPH.
You usually don’t feel the trailer brakes holding you back at higher speeds as you did at the slower speed. The reason is that the trailer’s momentum pushes you and the tow vehicle, so slowing down is not as noticeable. That is why you always want to do it at slower speeds first to get the actual feel of the brakes and that the braking force is working.
Next, press the brake pedal down under normal pressure like you would any stop at this speed. You should feel at this speed that the truck is slowing down almost as it normally would without a trailer. I say almost as normally because there is some braking loss with the trailer, so there will be slower braking times, but not by much.
If you feel that your truck brake is doing all the work and you are not stopping like you normally would adjust the gain so you feel you are getting a safer stopping distance.
Step 3: Adjust at a slow speed (again)
Yes, this is a repeat of Step 1. When on the higher speed test, you likely needed to make an adjustment. With that, you want to make sure that the slower speed and stopping setting feel right and that you are stopping as we outlined in Step 1. Remember, at these lower speeds, and you want to feel the trailer pull you back a little once you barely push the tow vehicle pedal down.
Final Thoughts
Adjusting trailer brake gain is a task that doesn’t have a universal solution due to varying setups. Factors like trailer load, tow vehicle, braking power, and brake controller differ for each rig. However, there are steps to help you find the right gain setting. Start by loading your trailer to a typical weight and ensuring electric brakes are in good working condition. Then, follow a three-step process: test at a slow speed to feel the trailer brakes engage without jerking, assess braking performance at a higher speed, and retest at a slow speed to confirm adjustments. By following these steps, you can set the trailer brake gain for a safer and smoother towing experience.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.
