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RV 101: Why should I use a secondary braking system when towing?

If you’ve ever tried an emergency stop on a six percent grade, in wet weather and in a 37 foot RV with a tow vehicle, then you probably already know why you need a supplemental braking system for your tow car. Even with downshifting and judicious use of an exhaust or engine brake there’s no overcoming Newton’s three laws of motion as presented in the “Principia Mathematica Philosophiae Naturalis” of 1686, the leading RV magazine of the time. Of course if you didn’t know this, then you’re probably reading this article from your hospital bed.

Newton’s first law states that, “Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.” Which is why you have hydraulic or air brakes on your RV! Newton’s third law postulates, “For every action there is an equal and opposite reaction.” This means that even if you stop your RV, your tow car will still maintain its forward velocity, which in turn brings his second law into play, “The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma.” This is Newtonian gobbledygook, but essentially means that unless something acts to stop your tow car it will continue to move forward like a ram, using the back of your RV as the brake. Naturally in an emergency stop, this could cause a wee bit of damage to both your tow bar and also to the frame of the RV to which it’s attached. However, regular wear and tear will bring about the same outcome by unnecessarily stressing components on your tow bar and RV. For your own safety, for the safety of other road users and for your own financial peace of mind, you need to install some form of braking system on your tow vehicle. This should preferably not be the braking system employed by the cavemen Slag brothers in their Wacky Races Bouldermobile.

Nearly every State in the Union either mandates some form of auxiliary braking system for tow vehicles, or limits the weight of the vehicle that may be towed. There are a number of products on the market that you can choose from. Road Master manufactures two “proportional” braking systems, the Even Brake ($1250) and the Brake Master ($800-$1200). These systems act in the same way, applying proportional pressure to the brakes in the tow vehicle every time you use the brakes in the RV. The Even Brake is a portable unit that is placed in the driver’s foot well in the tow car. It is attached to the brake and connected to the vehicle’s 12 volt power supply. There is a wireless monitor that plugs into the 12 volt supply in the RV which emits audio tones and delivers text messages on the LED screen to advise you of the current braking condition. By contrast, the Brake Master is a stainless steel air cylinder that requires a fixed mount on the floor of the driver’s compartment. It is then connected directly to the RV’s hydraulic or air brakes (some additional modification may be required to both the tow car and the RV). There is a simple red warning light that is fitted to the dashboard in the RV to tell you when the brakes have been applied in the tow vehicle. This no frills system is extremely reliable and, having used both the Even Brake and the Brake Master systems, my choice would be with the latter. However, there are a number of competing products available such as the Toad Stop, Brake Buddy ($1150-$1500) and SMI Manufacturing's Air Force One ($1100) which all have their advocates and detractors.

All supplemental braking systems will help reduce wear on both the tow bar and chassis of the RV. A good proportional system, applying pressure to match your braking in the RV, will also reduce wear on the brakes in the RV and the tow vehicle. A potential problem with all braking systems that draw power from the tow car is that your battery can run flat. Road Master addressed this problem earlier this year when they released the Automatic Battery Disconnect ($177) and there is also the Toad Charge  ($109) which delivers up to five amps to your tow vehicle battery to ensure that it remains charged. If you opt for a Jeep as your tow vehicle, you will undoubtedly need to purchase one of these as someone at Jeep decided that the perfect all round 4x4 off-road vehicle (capable of being flat towed) somehow did not require a built in charging system. There is nothing like endearing yourself to your Zion Canyon campground neighbors when you have to ask a Ranger to jump start your immobilized tow vehicle on a one-way, single lane road where no one can pass you. Oh, the joys of camping!

Suggested sites: If you are doing research RVupgrades.com has a good selection of braking systems, and their respective price, represented on a single page.

© Copyright 2009 Julian L. Gothard. Protected pursuant to the provisions of the Berne Convention. All rights reserved.

 

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