RV Tech Tips with Mark Polk
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Thursday, August 30, 2007

Trailer sway is dangerous, be careful

Yaw, more commonly known as sway in the RV industry, is a bad word for trailer owners. The definition of yaw or sway is a side-to-side movement. Nothing will ruin the way you feel about camping faster than the first time you experience trailer sway.

You have tent camped for years and now you decide its time to move up to a pop-up. You go to your local dealership and find a pop-up with the perfect floor plan for you and your family. The sales person knows that it will be close to the maximum weight that your vehicle can tow. He really needs a sale because things have been slow. Rather than risk losing the sale he decides not to explain the added expense of the proper hitch work to safely tow your new trailer.

Video: Losing a trailer for any reason when you tow it can turn into a disaster.

You're all packed up for a weekend getaway. You made all of your pre-trip checks and you're eager to leave. You load the most precious cargo you have, your family, into your tow vehicle and head out. Everything seems fine. You take the on-ramp to the interstate. You're cruising at the speed limit enjoying the music on the radio. Suddenly out of nowhere a transfer truck going 20 miles per hour over the speed limit is passing you as if you're sitting still. The pop-up is pulled into the draft created by the truck. In an attempt to correct this totally unexpected event you over steer and the trailer begins to go the opposite direction. Not really sure what to do you hit the brakes and turn the steering wheel to the left, then to the right. Now, that one-ton trailer behind your sport utility vehicle is veering sharply from side to side and begins to affect what little control you have over the vehicle. The results are catastrophic.

Ok, since this is just an article, lets start over and fix this before you even realize there's a potential problem. You purchased your pop-up from a reputable local RV dealership. At the risk of losing the sale your sales person explains that you will require some specialized hitch work to pull your new trailer safely. You are a bit skeptical, feeling like they just want more of your money. Besides, your father never needed any of this stuff. He just hooked the trailer unto the ball and went.

You decide to give the sales person the benefit of doubt and listen for a minute. He shows you in his book that your tow vehicle is rated to tow a maximum of 3,500 pounds. Then he explains what you must factor in to that tow rating. It includes the weight of your new camper, any after market accessories, like the roof mounted air conditioner and battery the dealership is going to install, all of the cargo and personal belongings that you load in the trailer and in the tow vehicle, and the weight of the passengers in the vehicle. Now all of the sudden the sales person has your undivided attention. You had no idea that all of this had to be considered.

He shows you the weight label on your new trailer. The unloaded vehicle weight (UVW) is 2,100 pounds. The air conditioner weighs 100 pounds and the deep cycle battery weighs 50 pounds. To be safe he estimates that you will carry about 300 pounds of cargo, and then adds another 300 pounds for your wife and two children. You are amazed how fast things add up.

Now you have 2,850 pounds instead of the 2100 pounds that you thought it was. It isn't over yet. Your sales person starts to explain that every state has different requirements on how much a trailer can weigh before it requires trailer brakes. In your state the weight is 3,000 lbs., but your dealership has brakes installed on any trailer they order that weighs over 2,000 pounds. He explains that even though your vehicle is rated to tow 3,500 pounds the brakes on the vehicle were designed to safely stop the vehicles weight, not an additional ton and a half being pulled behind it.

HE TAKES YOU to the parts department and shows you a brake controller and explains that this is what activates the trailer brakes and the dealership will install it when they do the wiring for the trailer lights. You like the features that he explained about the brake controller. The fact that you can manually adjust the amount of braking action so that when you hit the brake pedal the tow vehicle and the trailer work together to stop the weight in a reasonable amount of time. What you really like is the part he explained about the manual override lever that activates the trailer brakes without using the vehicle brakes.

He said if you're on a steep grade and you don't want to prematurely wear out the vehicle brakes you slowly slide the lever and the trailer brakes will slow you down. But what really sold you on it was when he explained that if the trailer starts to sway you could gently move the lever, activating the trailer brakes, to help straighten the trailer out. He went on to explain that trailer sway is one of the biggest potential problems that you can encounter while towing a trailer. He points out some of the factors that contribute to trailer sway.

First and foremost poor trailer design contributes to trailer sway. When there is too much weight behind the trailers axles causing the tongue weight to be less than 10% of the trailers weight it has a natural tendency to sway.

--Incorrect tire inflation
--Improper weight distribution hitch adjustments
--No sway control on the trailer
--Crosswinds
--A transfer truck passing from the rear of the trailer
--Descending inclines
--Towing speeds
--Tow vehicle not properly matched for the trailer
--Improper loading, overloading and poor weight distribution

He took the time to explain that for the trailer to pull properly the manufacturer recommends that the tongue weight resting on the ball mount should be 10 to 15% of the total trailer weight. He said if it is more than 15% they have what is called a weight distribution hitch that takes the additional tongue weight and distributes it to the axles on the tow vehicle and the trailer where it should be, and if it is less than 10% when you load your cargo you distribute it to add some additional weight on the tongue. He looked up the pop-up you were buying in the brochure and the tongue weight was 305 pounds. With the air conditioner installed and your cargo loaded you would be between the 10 to 15% range. He explained that a weight distribution hitch was more commonly used with heavier trailers and in some cases with pop-ups depending on the tow vehicle, but in this case it would not be required.

The next thing he asked was if your vehicle had a receiver. You reply, do you mean a hitch? He explains that the part that is bolted to the vehicle is called a receiver, and he shows you a chart that has several different classes of receivers depending on the amount of weight you will be towing. The class II receiver was rated for 3,500 lb. gross trailer weight and 300 lb. max tongue weight. For a small difference in price he recommended a class III receiver rated for 5,000 lb. gross trailer weight and 500 lb. max tongue weight since your trailers tongue weight exceeded 300 lbs.

WITH THAT DONE he said let me show you the one component that our dealership strongly recommends to anyone purchasing a pop-up. He walked over and picked up a part from the shelf. This is called a friction sway control. We mount one end of it to the ball mount and the other end to the tongue on the camper. You adjust the amount of friction by turning the lever clockwise for more friction and counter clockwise for less friction. He explained that you turn it in 1/8 increments until you get it adjusted where you feel comfortable. This will not totally eliminate sway, but once the forces of sway are in motion it will dampen the sway and help you control it when you're towing your camper.

Well, he said, that about does it. For less than 10% of the price of the pop-up you can get all of the hitch work done and ensure that your family is safe when you go on a trip. At this point you're convinced that the sales person has your best interest in mind and was not just trying to make more money.

You're all packed up for the first weekend getaway with your new pop-up. You make all of the pre-trip checks that the dealership explained to you and you're ready to go. You load the most precious cargo you have, your family, into your vehicle and head out on a new venture. You take the on ramp to the interstate. You're cruising at the speed limit enjoying the music on the radio. Suddenly out of nowhere a transfer truck going 20 miles over the speed limit passes you as if I you're sitting still. You feel a slight movement behind you. It was just enough to remind you that you're pulling the pop-up. You look at you're watch and tell the family that you should be at the campground in a couple of hours.

Knowing how to react when a trailer begins to sway can be the difference between your safety and disaster. -- Mark Polk

Learn how to tow your trailer the safe and easy way. In his best-selling DVD RV expert Mark Polk shows you everything you need to know about towing, weights, hitch work and backing. Essential viewing for new trailer owners. Learn more or order.

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Tuesday, August 21, 2007

RV Refrigerators: cools like a home model but differently


The refrigerator in your RV operates off LP gas or electricity. Its different from the refrigerator in your house. An RV refrigerator doesn't have a compressor, or any moving parts for that matter. It works off of the principle of absorption. Instead of applying cold directly, the heat is drawn out, or absorbed. The theory is, when there is an absence of heat there is cold. Basically your RV refrigerator uses heat, either from an electric heating element or LP gas flame. The heat starts a chemical reaction and then through evaporation and condensation causes it to cool. It also works off of gravity, freezing the freezer compartment first and then dropping down to the refrigerator compartment.

The initial cool down process can take four to six hours. You should turn the refrigerator on the day before you plan to leave on a trip, and before you put any food in it. When you do load the refrigerator the food you put in should already be cold, and the food put in the freezer should already be frozen. Putting cold food in the refrigerator, rather than adding warm food, lets the refrigerator work more efficiently. One common mistake made is to over pack the refrigerator. There has to be space between the foods to allow for air to circulate throughout the compartment. In most situations you will have access to a store where you can buy food. A two to three day supply should be enough.

Try to limit the amount of times you open the refrigerator or freezer doors and the length of time you leave the doors open. Every time the door is opened it loses a few degrees of heat. On a hot summer day it won't take long to lose all of its cooling capacity. --Mark Polk

Learn more about using your RV and its operation with Mark Polk's best-selling DVDs, books and eBooks.

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How to keep your RV freshwater safe to drink


Here are some ways to ensure your RV water system is safe to use. There are no guarantees that any water is completely safe to drink, but if we take certain precautions we can keep our RV water system safe to use. So where do we start? Let's take a look.

The water system in your RV provides the water that you drink from and the water you use to wash dishes and take showers with. We cannot assume that it will stay safe and fresh like the water system in our home. Contaminated water is extremely dangerous. We not only have to deal with a water system that hasn't been used for sometime, but when we travel in the RV we hook our water system up to a different water source every time we stop to spend the night some where. We hook up to city water, well water, and eventually contaminated water. You've probably heard people say don't drink the water if you go to Mexico. Well that can be true anywhere. We stopped at a campground one night just to get a few hours of sleep and I didn't bother to use the water filter. The water coming out of the faucet was cloudy and had small particles suspended in it.

Possibly the most important step you can take is to keep the fresh water system sanitized. At a minimum you should sanitize the system every spring when you take the RV out of storage and any time you notice stale water or an odor. Its really quite simple to do.

You can start by draining the water heater. Go to the outside compartment where the water heater is located. The drain plug, or pet*censored* is located in the bottom left hand corner. Remove the plug and open the pressure relief valve on top of the water heater to assist in draining. CAUTION: NEVER drain the water heater when its hot or under pressure.

Next you need to locate the low point water line drains. It may take a while to find them, but I assure you they are there. There will be one for the hot and one for the cold water lines. This is the lowest point in the water system. Open these and let the water drain out.

Now, find the drain for the fresh water holding tank and drain all of the water from it. At this point you can turn the water pump on for a moment to force any remaining water out. Do not let the pump continue to run once the water stops draining. Close all of the drains. What we have accomplished so far was to evacuate the majority of water from the system.

Now take a quarter cup of house hold bleach for every fifteen gallons of water that your fresh water tank holds. Mix the bleach, with water, into a one-gallon container and pour it into the fresh water holding tank.

Fill the fresh water tank almost completely full of water. Turn the water pump on, open all hot and cold faucets and run the water until you smell the bleach at each faucet. Close the faucets. If its possible drive the RV or pull the trailer so the water can move around to assist in cleaning the entire tank. Let it sit for at least 12 hours. Drain the entire system again and re-fill the fresh water tank with potable water.

Open all of the faucets and run the water until you no longer smell any bleach. It may be necessary to repeat this process again to eliminate all signs of bleach from the water system. Once this is done it is safe to use your water system.

If you follow these simple steps you can rest assured that the fresh water system in your RV truly is fresh. -- Mark Polk

Learn more about using your RV and its systems with Mark Polk's best-selling DVDs, books and eBooks.

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