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Roadmaster InvisiBrake: The Built-In Towed Car Braking System

Roadmaster InvisiBrake: The Built-In Towed Car Braking System

If you’re flat-towing your car behind your motorhome like we did full-time for over 20 years, there’s no need to lug a portable braking system around, thanks to the Roadmaster InvisiBrake.

Flat towing a car (4 wheels down) behind a motorhome requires an auxiliary braking system to handle the car’s weight. Besides normal braking, it’s critical for bringing the towed car to a stop in the unlikely event it breaks away from the motorhome.

In this post, we share what we know about the Roadmaster InvisiBrake and how we liked it once it was installed in our toad car.

Do You Need a Braking System When Towing a Car?

An auxiliary braking system is required by law in most of North America. A toad braking system not only manages the extra weight of the car but also brings it to a stop automatically in the unlikely event that it should disconnect from the RV.

So, an auxiliary braking system contributes to safety and reduces strain on your RV’s brake system. Your motorhome will not only brake more easily but the wear and tear on those brakes will be reduced by your supplemental braking system. It basically lets each vehicle’s own brakes handle stopping it, just like they were designed to do.

What Is the Roadmaster InvisiBrake?

InvisiBrake is a fully automatic supplemental braking system that uses the electrical connections already in place on your towed vehicle to apply its brakes when you apply your motorhome’s brakes. InvisiBrake uses the same electrical signal that activates the towed vehicle’s brake lights to activate the InvisiBrake system at the same time.

InvisiBrake is small (8″ x 8″ x 2″) and is usually mounted under the driver’s seat or a rear seat, behind interior panels, or in the trunk, so it’s out of sight and doesn’t take up much space.

An InvisiBrake unit

The InvisiBrake is only 8″ x 8″ x 2″ and can be installed in an out-of-the-way place that makes it… well… invisible! (Photo source: Roadmaster)

Once it’s installed, there’s nothing more to do. You simply plug in your umbilical cord when you’re hooking up as usual, and you’re done. It stops the car normally and also includes an emergency system to stop the car in the unlikely event of a breakaway.

InvisiBrake also connects directly to the towed vehicle’s battery and trickle-charges it as you tow, so InvisiBrake won’t drain the battery. It’ll work in just about any towed vehicle with vacuum-powered brakes, including hybrids and continuous power assist braking systems.

Why We Switched to the Roadmaster InvisiBrake

Our old braking system had been giving us trouble for a while, so we had Roadmaster install a new InvisiBrake on our 2003 Honda CR-V at their factory in Vancouver, WA.

We’d been having problems with our original braking system for several years, requiring troubleshooting, repair, and adjustment on a more and more regular basis. It was an old discontinued model that required a separate vacuum pump to keep the car’s brakes working so that it wasn’t just pulling on a dead brake pedal. That pump needed to be installed on the RV with an air line connected across the tow bar to supply the vacuum to the car’s braking system.

With the old system becoming more finicky every year, we knew it was time to replace it. We looked at all of the options available, including systems that tap into the air brakes on the RV. We chose the Roadmaster InvisiBrake for several reasons.

The Roadmaster Invisibrake is Invisible

It truly is pretty much invisible. With the main unit installed in the storage area in the rear of our CR-V and the brake actuator components under the driver seat and up under the dashboard, everything is out of sight.

Nothing to Set Up

There’s nothing to take in/out of the car to get it set up for towing. Everything is built in and ready to go. Simply hooking up the tow bar and cables connects everything that’s needed to operate the InvisBrake. For us full-timers who keep our vehicles for a while, it’s a perfect hands-off solution.

No Additional Connections Required

The Invisibrake doesn’t require any additional connections/cables across the tow bar (like our old system did). The braking signal comes through the existing electrical umbilical, so there’s nothing extra to connect or set up. Besides being out of sight, it operates invisibly, too.

Built-In Vacuum Pump

Roadmaster’s Invisibrake includes a built-in vacuum pump to maintain the vacuum in the car’s braking system. This ensures that brake application is smoother and easier and that the system isn’t acting on a “dead” brake pedal. There’s no more need for an auxiliary vacuum pump.

The InvisiBrake and its built-in pump are completely contained inside the car. And since it’s powered by the car’s battery, a breakaway won’t separate the system from power… or the vacuum pump. If you want to test the system, a quick pull on the breakaway cord will apply the car’s brakes. Anywhere. Any time.

Charges the Toad’s Battery While Towing

The InvisiBrake system supplies charging to the car’s battery while we’re towing, ensuring that the InvisiBrake itself, and our car’s brake lights, don’t deplete it during long days of driving. The extra power comes across the umbilical cable from the RV as an integral part of that cable.

Doesn’t Tap Into the RV’s Air Brake System

We like the fact that it doesn’t tap into the air brake system on the RV. There are several options out there that do (including one from Roadmaster, called the BrakeMaster), but we’re more comfortable with a braking solution that doesn’t require tapping into our RV’s air brake system.

We know that those systems are tested and designed to ensure they don’t compromise the brake system’s integrity, and we know that they’re proportional, meaning that the same amount of brake pressure is applied to the car as you’re using on the RV, (as opposed to progressive, meaning that the car’s brakes are slowly and steadily applied, with increasing pressure, the longer the braking signal is triggering them).

But we’re still happier not tapping into our RV’s air system. Plus, we’d already had a progressive system on our CR-V for 17 years, and until we started having other problems with it, it worked fine.

Our Roadmaster InvisiBrake installed in our car.

Our Roadmaster InvisiBrake is installed discreetly in the storage area in the back of our 2003 Honda CR-V. It’s completely out of sight and out of the way, and we hardly even think about it back there. It simply does its job.

How Long Does It Take to Install InvisiBrake?

Although it’s possible to install the InvisiBrake system as a DIY project, we chose to have it professionally installed at Roadmaster’s factory in Vancouver, Washington. The system is a bit involved, and it’s important to have it done right.

You can have a local installer do the job for you. Or, if you have plans to be in the US Pacific Northwest, you can have it done at the Roadmaster factory like we did.

Installation of the InvisiBrake system should take a few hours, including an overview of the system from the installer. Once the InvisiBrake is in place, it’s always ready to tow.

Here’s our video detailing the entire process and the InvisiBrake system itself:

How Do We Like the InvisiBrake System?

We used the InvisiBrake by Roadmaster in our CR-V for the last few years we owned our Class A motorhome, and we loved it. Combined with our Roadmaster Nighthawk tow bar, we were more confident than ever that our Honda would safely and securely follow us wherever we towed it. And it did. For even more information, see our post on towed car brake systems.

Roadmaster InvisiBrake Supplemental Braking System

ROADMASTER 8700 InvisiBrake Supplemental Braking System
  • Can be installed out of sight
  • Progressive Braking

And here’s a coupon for the Roadmaster Nighthawk Tow Bar, our favorite tow bar that we used to tow our Honda CR-V behind our motorhome:

Roadmaster, Inc Logo
Roadmaster Nighthawk RV Tow Bar RVgeeks Package

Call Roadmaster at (800) 669-9690 to order your Nighthawk tow bar factory direct and tell them you want “The RVgeeks Package”. You'll receive a FREE Tow Bar Cover & Hitch...Show More

Call Roadmaster at (800) 669-9690 to order your Nighthawk tow bar factory direct and tell them you want “The RVgeeks Package”. You'll receive a FREE Tow Bar Cover & Hitch Receiver Lock to keep your new Nighthawk secure and looking great. Free Shipping is also included!

The Roadmaster Nighthawk is our favorite RV tow bar. The non-binding latches ensure you'll have an easy time disconnecting, no matter how the RV and tow car are positioned. Longer arms make connecting and disconnecting easier. And the LED lights along the arms improve safety and visibility when towing!

Check out our latest Nighthawk video here

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Monday 4th of March 2024

Installed an InvisiBrake and love it! Thanks guys!


Monday 4th of March 2024

Awesome! Great to hear, David!

Ethan Bernstein

Sunday 4th of February 2024

Being a sophomore in the RV world, we have a Demco SBS Stay-IN-Play DUO Supplemental Braking System that the shop that specializes in installing tow system recommended us to have for our Jeep Wrangler. We went to Alaska and back without much problem other than dead batteries (this Jeep has two batteries) due to long towing. We resolved by running the Jeep engine during breaks at least once a day for really long drives such as between Alaska and lower 48. What do you know or think of this braking system?


Sunday 11th of February 2024

Hi Ethan. Demco is a good, respected name in RV equipment. We know a couple of people who have had Demco towing systems (towbar only, not with the braking system), and they've been very happy (towed car always ends up at the same place the RV does 😉). The Stay-IN-Play DUO is very similar to the Roadmaster Invisibrake (installed in the towed vehicle, includes a vacuum pump to maintain brake system vacuum level to avoid braking with dead pedal, etc)... but the Invisibrake includes a feature to pull power from the light circuits (as powered by the connection to the motorhome) to supply charging power to the towed car's battery, so it doesn't drain. But it sounds like you've come up with a solution already.


Sunday 4th of February 2024

Y'all have confused me with this one. You talk about InvisiBrake being proportional but their add says it is progressive. Which is it?


Sunday 4th of February 2024

So sorry for the confusion. We have corrected that editing error. Thanks so much for pointing it out. The InvisiBrake is indeed progressive, but we have found it to work extremely well, and are very happy with it.

Barry Barnes

Sunday 4th of February 2024

I have a 2,300 pound 1978 MG MGB roadster British sports car with hydraulic brakes plus booster. Will this work on it?

mike cannon

Tuesday 6th of February 2024

@Barry Barnes, Hello Barry, this Mike Cannon with Roadmaster Manufacturing. If you would like to get more information on your special application, you can reach me at


Sunday 4th of February 2024

We'd suggest contacting Roadmaster directly, Barry! Assuming that the MGB (awesome car, by the way!) has vacuum-assisted hydraulic brakes, it should work just fine. The system uses its own onboard vacuum pump to keep the vacuum assist on the car primed and ready to go. Without that, we don't think it's compatible, since it would be dead-pedaling the brakes which isn't good for the Invisibrake OR the car.


Sunday 4th of February 2024

Can this be installed with a Blue Ox towing system?


Sunday 4th of February 2024

It should be compatible, Rob. The only thing that might need some "tweaking" would be the wiring inside the umbilical cable. But everything else for the Invisibrake is wired into the car's wiring to receive the signals about braking, etc.

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