RV Tech Q&A: February 2019

Winterizing Variables

Capital Red Q for tech questionI am going into my second winter of RV ownership. Last year I used liquid antifreeze to winterize my RV. I winterized it in November, and the RV sat until March when I took it out of storage. This year we want to take some trips in winter. I don’t have a heated space to store the RV, and it seems impractical to winterize and de-winterize with liquid antifreeze every time we want to use the RV. I noticed in the November 2018 issue of your sister publication, MotorHome, in the Wheels & Gear section that Viair makes a kit for winterizing an RV with compressed air.

While this would seem to be a much easier method of winterizing and de-winterizing an RV for winter utilization, I am concerned that I wouldn’t be able to adequately winterize the icemaker, water dispenser in the refrigerator and the washing machine. This has to be a common issue, and I am wondering if you could offer suggestions regarding compressed air for winterizing an RV.

Lynn Fees | Kellyville, Oklahoma

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Blowing the lines out with air is an effective winterizing technique for faucets and the general RV water system, but, as you suggested, it may not be as effective for some mechanisms that use water. A faucet can be fully opened, and the air forces out the water. An icemaker, washing machine and so on aren’t that easy. The best idea would be to read the owner’s manual for each device and see what the manufacturer recommends for a winterizing technique.

I don’t have a suggestion about how to easily perform this job when you want to use the trailer every few weeks during the winter. All it takes is one cold night, and your gear can be frozen and damaged. One alternative is to provide some type of low-level heat source to keep things from freezing inside, and if you have 120-volt AC shorepower available, a small electric heater would do the job. Otherwise, you may need to use some RV antifreeze and run it through the devices you have in mind as a means of effectively winterizing the equipment.


Tire Traction

Capital Red Q for tech questionI have a 2016 Ford F-250 rear-wheel-drive diesel with an 8-foot bed and rear-axle lock. Stock tires are General Grabber HTS LT245/75R17 LRE. I tow a 32-foot fifth-wheel that weighs 11,000 pounds, with a 1,600-pound pin weight. Sometimes I experience wheel-spin starts on wet pavement and must really tickle the throttle. Grass shoulders are tricky, especially when wet. The axle lock helps some. The trailer brakes are not dragging.

Can you advise of a more aggressive tread pattern? I do not want noisy, heavy lug tires. I run my rear truck tires at 80 psi. There is a decent footprint. The fronts are at 65 psi. When towing, it’s a smooth, quiet ride.

The USA-made Goodyear load range E tires are run at 70 to 75 psi. I love these tires. A note to readers: Get rid of your imported trailer tires and buy the Goodyears! You will be very happy with these much safer tires.

Fred Johnson | Ridge Manor, Florida

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Choosing a tire with more traction is going to call for some research. An online user forum for a specific tire type will probably provide details on tread noise and longevity. You don’t need a truly aggressive mud-and-snow tire, but something rated for all-season use might do the trick. Another good resource would be www.tirerack.com. The website has lots of test data and ratings for all kinds of tires.

Be sure to choose a tire with good tread siping, which is the small transverse slots in the tread area. These are great for enhancing traction on snow and ice, and they work well on wet pavement. We’ve also experienced the slipping rear wheels on startup from a dead stop, and feathering the throttle as you’ve done is a good way to address the slippage. It happens more often with travel trailers when the weight-distributing hitch has shifted some of the rear-axle weight forward, but even a fifth-wheel can get the slips now and then, too.


Trailer Weight and Balance Calculations

Capital Red Q for tech questionAfter reading several articles about weight distribution and calculating weight using scales, I have a question about adding weight to rear-bumper storage racks. Can I calculate the change to tongue weight without multiple trips to a set of scales? Is there a formula that can be used with known added weight, known distance between axle(s), and the hitch point and axle(s) and center point of the rear-bumper storage rack?

It would also make a difference with dual axles whether you are calculating from the front or rear axle. Seems to me that when adding about 100 pounds (small generator and tools) to the rear-bumper area where a rack is to be placed, the fulcrum would be the rear axle. Using physics, is there a way to measure the distance from the rear axle to the hitch and the distance from the rear axle to the center point of the rear storage rack to determine how much the 100 pounds takes from the hitch point?

Tim Pasquarelli | Anthem, Arizona

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There is probably a way to measure all these things using physics and math, Tim, but we don’t have any procedures or formulas for this. First, as for using the front or rear axle as the pivot point, a trailer suspension includes an equalizer component, and the difference would be minimal to nonexistent in the real world, as opposed to just using the center point between the axles.

I am not a top-notch mathematician, but if the hitch-to-axle and axle-to-bumper distances are equal — but they probably aren’t in your case — then 100 pounds added in back would be 100 pounds less up front. In theory, if the axle-to-rear-bumper is just 80 percent of the axle-to-hitch distance, then 100 pounds out back would be just 80 pounds taken off the hitch. A better mathematician than I could elaborate more on that theory.

But consider real-world trailer towing. Are you always hauling the exact amount of water in the freshwater tank and holding tanks? Is the cargo load in the trailer always the same, front and back? Even if you have precise calculations to determine weight shift fore and aft, the real world can step in and alter the results. In the end it’s always good to visit a scale and verify your results to determine balance. Insufficient hitch weight can lead to trailer sway and instability — characteristics you’ll want to avoid regardless of how you arrive at your figures.


Trailer Jacking Suggestion

Capital Red Q for tech questionIn regard to James Cooper’s “Trailer Jacking” comments in the September issue, this is what I have done on two occasions with my double-axle fifth-wheel. I made a double-ended ramp of 2-by-8-inch lumber with a 30-degree slope from the horizontal at each end. The ramp is three layers of 2-by-8 lumber. The bottom layer is 28 inches long, the middle is 23 inches long, and the top layer is 18 inches long. Screw all three layers together, centering them on the base layer. Then cut the two slopes.

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The flat surface of the top layer should be about 2 inches longer than the tire footprint. Pull or back the trailer onto the ramp with the good tire centered on the top-layer flat surface of the ramp. This will carry the flat tire off the ground and should allow enough clearance to remove and replace the flat.

If not, then you could place a jack under the flat tire’s axle to raise it enough to gain clearance without raising the weight of the trailer but only the axle/tire unit and compressing the leaf spring. Remove and replace the flat. Before moving the trailer onto the ramp, be sure to break loose lug nuts, or you will be spinning the flat tire, not the nuts.
James A. Hofbauer

Huntington Beach | California

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Thank you for the tire-changing process explanation, James; it makes a lot of sense, but we still stick with the trailer manufacturer’s recommendation to never jack using the axle. There are jacking accessories on the market that accomplish exactly the same thing, but your 2-by-8-inch lumber method is economical and easy to assemble and use. We appreciate your useful suggestion.


Have a Tech Question?

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Man with grey beard and wearing blue shirt leaning over open car hoodJeff Johnston served as technical director of Trailer Life for 20 years and has been an RV enthusiast, mechanic and writer since he could hold a wrench. In his monthly RV Clinic column, Jeff replies to Trailer Life readers’ technical questions about RVs and tow vehicles. He also serves as associate producer of Rollin’ On TV, a nationally syndicated television program for RV enthusiasts.


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