May 2007 RV Questions & Answers by Mark Polk

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*NOTE: At Mark's discretion, material might be edited to suit a wide audience. Due to the large volume of material and correspondence we receive, individual replies might not be possible, nor can we acknowledge receipt of submitted material. Selected questions will be answered in future issues of our RV Education 101 newsletter and on our site. Thank-you for your understanding.

Q: We have a Pop Up and my husband and I can never seem to back it in to the camp sight where we want it to go. Do you have any advice or ideas?

Mark says: I have a method that has always worked well for me with two people working together. First decide who will drive and who will give directions. Let’s say your husband is driving. For this to work you are his eyes and he needs to do exactly what you tell him. When you are ready to back it in, you stand in front of the vehicle where you can see the trailer and communicate with your husband. He puts his hand on the top of the steering wheel and slowly turns the wheel in the direction you tell him. If you want the back of the trailer to go to your right you tell him to turn the steering wheel to the right. If you want it to go to the left tell him to slowly turn the wheel to the left. Don’t get upset if you need to pull forward and start over. With a little practice you’ll be backing like the pros. There is an excellent video available that not only demonstrates methods for backing a Pop Up, but it covers everything you need to know about using Pop Ups too. http://rveducation101.com/detailedinformation.asp?ID=1454

Q: After we decided to buy a travel trailer the dealer told us we would need to spend another $1,000 dollars on hitch work. Isn’t this a little unreasonable?

Mark says: The dealer should have explained the importance of proper hitch work during the sale. It is for your own safety and the safety of your loved one’s. If your particular purchase requires a weight-distributing hitch, dual cam sway control, electric brake control and wiring then 1,000 dollars is not unreasonable. Any reputable RV dealer will not sell the trailer without the proper hitch work.

Q: I have heard people talk about the 75% rule of thumb for towing. How does this work?

Mark says: There is some confusion on this subject. A lot of people say that you take the manufacturers tow rating for a vehicle and multiply it by 75% and this is the maximum weight you should tow. For example a tow rating of 8,000 pounds X 75% = 6,000 pounds. The 75 % rule is designed to build in a margin of safety. The way that I understand it and apply it is that you take the Gross Combined Weight Rating (GCWR) of the tow vehicle X 75%, and the Gross Vehicle Weight Rating (GVWR) of the tow vehicle X 75%. Once you determine this you subtract the two and this is the maximum weight you should tow. Using the same example above that vehicles GCWR is 14,000 pounds X 75% = 10,500 pounds. The GVWR is 8,800 X 75% = 6,600 pounds. 10,500 minus 6,600 = 3,900 pounds. I apply this rule if you plan to tow in high elevations. A gasoline engine looses 3 to 4 percent of its power for every 1,000 feet above sea level. The 75% rule compensates for that lose in power.


Q:My 2006 Toyota Tundra Quad Cab truck has a GCVWR of 11,800 (12,200 from another source), let's be conservative and say 11,800. The truck does have factory installed towing package. Tow rating on truck with tow package is 7100lbs according to owners mannual. Trailer has dry weight of 5190 and gross weight rating of 6500lbs. My estimates on cargo and add on's, I have estimated at around 850 to 900lbs. If we did any dry camping it would be very rare. So I'm not allowing for a lot of water weight.

So, loaded trailer weight should be about 6040lbs. Looking at it from this point I have almost 1100lbs of slack. But from at GCWR I'm pushing the envelope on weight. I do have a oil cooler with tow package. I have a prodigy brake controller, and I'm going with your recommendation and purchase an "Equalizer" hitch. They are kinda of high $$$, but I feel it will be money well spent. My truck also has a tow mode on the transmission. It takes it out of overdrive and runs the truck in 3rd gear. (There goes gas mileage!!)

The Jayco trailer I am looking at and the weight of the truck, put me at 98% of the GCVWR. I know the lower percentage the better, but what I can't get a straight answer on is being at 98% will the truck still pull O.K. I don't want to put the truck in a bind, and I don't want to spend 20 minutes trying to get up a hill either. I have weighed my truck on a scale as recommended. It was loaded and full of gas. I probably went a little overboard putting fire wood in the bed to get some extra weight. Just trying to figure on high side. I have also taken dry weight of trailer and have added for propane, hitch weight, some water, and personnel food and gear. (Food & Gear I used about 350lbs.) Just some added info. Based on the length of the wheel base of my truck. I'm just about at the maxium on trailer length too. I am going to purchase weight distribution and sway control hitch. I just can't get a clear answer on towing ability at these weights from anyone. You're not trying to sell me a travel trailer, so any information you can provide me will be helpful.

I also have purchased your Video Series: http://rveducation101.com/detailedinformation.asp?ID=2169on RV's and have gained a lot of information. This is our first RV and we have a lot to learn. We need all the help we can get.


Mark says:I had a chance to review the information you sent. I have always said if the tow vehicle tow rating is higher than the trailers GVWR you are in pretty good shape (as long as you don't overload the trailer). And the key to the GCWR is to keep it below the GVW of the combined truck and trailer which you are, even though it is at 98%, it is below. If you plan to pull the trailer in the mountains a gas engine will loose 3 to 4% of its power at higher elevations and you may want to re-calulate your figures.

Copyright 2007 by Mark J. Polk owner of RV Education 101

RV Expert Mark Polk, seen on TV, is the producer & host of America's most highly regarded series of DVD's, videos, books, and e-books. http://www.rveducation101.com/

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