RV Tech Q&A: June 2019

New Tire Size Inflation

I have a 2013 Outdoors RV (ORV) Timber Ridge 26RLS travel trailer with an unloaded weight of 7,200 pounds and a 1,500-pound cargo capacity. The unit came with load-range D Goodyear tires and an ORV-recommended inflation pressure of 65 psi, the maximum for load-range D tires. I have since upgraded to load-range E tires. The maximum inflation rating for these tires is 80 psi. Should I run the new tires at 65 psi, ORV’s recommended inflation setting, or closer to 80 psi, the load-range E maximum?

John Goldsmith | Chilliwack, British Columbia

Make sure the wheels can handle the extra inflation pressure. Each wheel will be marked, usually on the inside of the rim or center, providing maximum load and pressure. If the wheels are rated for that extra pressure, that gives some flexibility.

Most quality tire manufacturers publish a chart of inflation pressures and weight ratings for each tire size, called a “load and inflation table.” A tire rated for its max load at 80 psi will have a reduced load rating at 65 psi, but if 65 psi provides enough to safely carry your trailer’s weight, that’s the pressure you should use. The lower air pressure will also have the effect of softening the ride on your trailer, thereby reducing the jarring road impacts transmitted to the trailer body.

To learn more about load and inflation tables, search the internet for your tire manufacturer, tire size and model. We also frequently cover this subject here in RV Clinic so you can find out more by going to the RV Clinic FAQ list and checking our archived RV Clinic letters on the Trailer Life website.


Loosening Stabilizing Jacks

I own a 2017 Prime Time Avenger ATI. I spray-lubed the stabilizing jacks with a silicone. When arriving at our campsite, I found two of the stabilizers would not stay tight. I have tried cleaning them, to no avail. Recently, all four are having the same problem. I purchased an aftermarket part to keep them from moving. However, as soon as I remove the crank, they begin loosening right away. I have never had this problem with my other trailers. Any suggestions?

Michael Stone | Ellenton, Florida

Most stabilizing jacks use a long-threaded rod, known as a worm gear, to drive the mechanism that tightens and applies the lift to the jack. It’s a feature of a worm-drive mechanism that prevents movement by applying pressure to its drive mechanism, so I’m truly puzzled about how these jacks can be coming loose once you tighten them up. Yours is the first such letter we’ve received about this, and there are tens of thousands of those jacks in use.

It’s possible the jack-pad feet are sinking into the ground when you start moving around inside the trailer, and that would have the effect of making them seem looser. Each jack has a metal pad that’s a few inches wide and long, but unless the ground is hard-packed soil or rock, those pads tend to sink in. If you place a larger foot under the jack pad, such as a piece of 2-by-6- or 2-by-8-inch lumber a foot or more long, you’ll likely find the jacks stay a lot more secure and don’t loosen as you’ve experienced.


Wheel-Bearing Grease Type

In the October 2018 RV Clinic discussions of wheel-bearing grease, there was no mention of grease type. Wheel-bearing grease can be made with two bases: lithium and sodium. Never mix the two as they do not work together. If you don’t know which is already in the EZ Lube axle bearing, you have no alternative but to disassemble, clean and repack the bearing so you will then know for sure which grease to use.

Personally, I never use the EZ Lube zerk fitting, as I have seen grease escape onto the brake shoes, even on factory-assembled axles when no one else has touched the axles. Plus, I like to inspect the brakes for function, wear and bearings, and install a new seal on a regular basis.

Jerry Ahlstrom | Reno, Nevada

Thank you for the heads-up on grease types, Jerry. That’s good to know and will help some of our readers.


Rubber-Roof Repair

We live on the coast in Georgia and have a 2004 Terry Quantum 32-foot travel trailer that has a rubber roof with most of the white coating worn off. What RV roof coating can you recommend?

Jay Stewart | Brunswick, Georgia

Dicor makes a rubber-roof repair kit called the Roof Renew Kit that’s designed specifically for renewing an EPDM membrane. It includes a cleaner/activator that’s sort of a primer treatment, plus a new rubber-coating material. In the event you have any tears, it also includes seam-sealing tape. I helped do a 32-foot trailer with this kit, and it works great. It’s a good way to extend the life of your RV’s roof.


Water-Tank Capacity, Fantasy Versus Real World

I purchased a 2019 Winnebago Minnie Plus 27RLTS fifth-wheel in July of 2018. It is supposed to have a 50-gallon freshwater tank and a 10-gallon water heater. I could get only about 30 gallons in the water tank. I bought it in Salt Lake City at Motor Sportsland, and the dealership could get only 31 gallons in it.

Winnebago is now saying that, although the tank measurements (length, width and depth) compute to 50 gallons, it should hold only 40 gallons because of the overflow hose being on the side of the tank. That 40 plus the 10 in the water heater add up to 50 gallons of freshwater capacity. Yes, Winnebago has changed the wording in its brochures since. We can still get only 30 gallons in a tank that is supposed to hold 40 gallons.

I know of two other people who have purchased the same RV with the same problem. Winnebago now wants me to take it to another dealer to make sure the tank is the right one and is installed properly. I will do this in the next few weeks. Is this a common problem? I feel like Winnebago is dancing me around until I get tired of fighting, but I’m not going to let it drop.

Leon Steele

Manufacturers sometimes play fast and loose with things like tank capacities. You may see a footnote that reads, “freshwater capacity includes 5- or 10-gallon water heater,” and that covers the irregularity.

For my own curiosity, I’d like to know how you, or the second RV dealer, know you’re adding exactly 30 gallons of water to the tank. I’ve never seen a water hose with a flowmeter calibrated in gallons or any other unit of measure, so I need to presume you’re adding the water using, for example, a 5-gallon bucket at a time. That’s a good way to
do it and would help keep them honest.

See Related Story:
RV Clinic FAQ:
Top 20 Tech Questions

The location of the overflow pipe fitting on the tank doesn’t make a difference in tank capacity if it’s designed and plumbed right. Some manufacturers go cheap and just use an L-fitting with the hose or pipe aimed at the ground, and, in that case, the tank can’t be filled past the fitting, as the Winnebago spokesperson told you. That lazy arrangement also means every time you drive, the water sloshes around, and a bit escapes through the overflow hose with each slosh. This is the voice of experience speaking: During a number of road tests, we’ve filled the tank at home and found that we were down 20 percent on freshwater when we arrived at the campground, without using any water en route.

If installed properly, the L-fitting is aimed up, with the hose or pipe making a U-turn at some point above the top of the tank and the drain-hose end pointed back toward the ground. As the water sloshes to that side, it needs to travel all the way up the pipe to the U-turn before leaking out, and that slows the excess flow considerably.

Ask Winnebago to take a second look at the overflow-line routing, and perhaps its service people can come up with the correct solution. You know, the one they should have used in the first place.


Linoleum or Plank Flooring?

I have an older Keystone Everest 32-foot fifth-wheel in which the carpet is getting worn. I would like to replace it with something easier to clean like linoleum. I’ve thought of using easier-to-install click-lock vinyl planks, but I’m concerned that they would not hold up to the flexing that occurs due to road conditions, especially on unpaved roads, which we frequently use to get to our favorite camping sites. Would I be better off going to sheet linoleum, even though it’s more work?

Joe Montoya | Santa Fe, New Mexico

Plank-type flooring is used by manufacturers in new RVs and for aftermarket conversions you described. It’s considerably more flexible than a single-sheet linoleum-type product because it’s made up of smaller, individual pieces and will flex. Just be sure to select a product that’s water-resistant due to the sometimes-rugged conditions to which an RV floor is exposed.


Jeff 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.


1 COMMENT

  1. Re: Greasable Shackles. Part of the instructions for the installation of the greasable shackles that came with my MorRyde suspension kit addressed the need to orient the bolts so that the opening mid-shaft for the grease to flow needed to NOT be where the weight of the suspension would prevent the flow. This would be most easily accomplished with a fore or aft orientation instead of up or down.

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