RV Tech Q&A: May 2020

Young child playing badminton in front of green bushes.

Rough Rider Fifth-Wheel

Red letter QIt seems that every time we go on a trip, while underway, cabinets open, stuff spills out and chairs are even overturned. This is all due to a trailer that rides rough. What can be done to make a 32-foot fifth-wheel ride smoother? I have long wondered why they don’t have air suspension as large truck trailers often do. Also, what are slipper springs?
Lee St. Clair | Polson, Montana

Green letter AThere are several things you can do to soften your trailer’s ride, Lee. If your fifth-wheel has significantly heavier-rated tires than it needs, you may be able to run them at a somewhat reduced tire pressure, which can make the ride less harsh. Use the same type of real-world trailer-axle-weight figure along with the load and inflation chart for your RV’s tires to see how you stand. Be sure to weigh the trailer to know the exact tire weights before checking into load and inflation adjustments.

You can also investigate a variety of aftermarket suspension options. There are numerous accessories available including replacement leaf-spring equalizers that incorporate softer suspension components all the way up to an aftermarket airbag suspension. These items all provide some relief from the notoriously stiff leaf springs used on most trailers and fifth-wheels. An internet search will reveal a variety of options including systems from MORryde, Roadmaster Comfort Ride, Lippert Components and others.

A slipper spring is simply a leaf spring, with its front end connected to the chassis by the usual single-pivot bolt in a fixed mount, but the aft end rides against a frame-bearing surface instead of using a shackle-and-bolts hanger assembly. This is the same setup that’s been used on commercial truck trailers for many years but can now be applied to our smaller RV chassis. The setup is now available for RV trailers, and the slipper is said to help smooth the trailer’s ride. Slipper springs also can’t be used with many of the other aftermarket suspension devices mentioned.

WD Hitch Use

Red letter QWhat is the deciding factor to determine the need for a weight-distributing (WD) hitch for pulling a travel trailer? Is it the hitch weight, the trailer weight or tow vehicle weight? My Nissan truck, with a 4.0-liter six-cylinder, will pull the trailer I’m considering buying, which weighs about 3,500 pounds and is about 21 feet long. Is there an option to a heavy hitch and spring bars? Or am I doomed if I don’t have that for this type of towing?
Greg Kreinbring | Hemet, California

Green letter AIn most cases, the use of a WD hitch is necessary when towing larger and heavier trailers. If you use a weight-carrying (WC) hitch ball, the leverage of the hitch weight will remove some weight from the front axle. That can result in squirrely handling and improperly aimed headlights, conditions a WD hitch can eliminate. With the spring bars set for a modest amount of tension, the handling and steering should improve dramatically over the WC hitch.

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The Andersen hitch is another option that uses chains instead of spring bars and has a built-in sway-control feature. If hitch weight is a serious concern, the Andersen may be a good option. The Fastway hitch is also somewhat smaller and might weigh less than a full-size WD-hitch setup.

If in doubt, start by hitching the trailer to your truck using a WC-hitch setup. Release the air pressure from the rear-axle airbags if you have them. If the aft end of the tow rig drops by more than 2 or 3 inches, there’s a good chance you need a WD hitch. Once you get the WD hitch adjusted, trial and error should guide you to the best spring-bar tension position. You won’t be sorry if you make the investment and take the time to set up your tow rig and trailer with the right hitch apparatus.

Ram 3500 Airbags

Red letter QI have a 2014 3500 Ram with dealer-installed Firestone Ride-Rite airbags. The ride is really rough, even with 5 psi in the bag when the truck is empty. I pull a 40-foot fifth-wheel, and the airbags really help to level the truck when loaded. I have heard that air accumulators installed before the airbags will help the ride to be smoother. Is this true? Is there some way to make the truck ride smoother without removing the airbags?
Bill Linford | South Jordan, Utah

Green letter AToday’s trucks are remarkably sophisticated, but a 3500 pickup, also called a one-ton, is a heavy-duty vehicle designed to handle a large load, and the stiffer suspension is going to create a rougher ride than lighter trucks. That’s something you can’t get away from in a 3500-series truck. And I don’t think that adding any accumulator tank in the airbag system would help.

At 5 psi, the airbags aren’t providing any support to speak of; that’s about enough pressure to prevent the airbags from collapsing. At that point (5 psi), the truck’s leaf-spring suspension is providing the support and the rough ride quality you’re feeling. You could try raising the airbag pressure a bit at a time, say to 10 psi, then 15, and so on as needed. With just a bit of lift provided by the lower pressure, a small portion of the load is transferred from the truck’s spring suspension and carried by the airbags. This could result in a softer ride.

It’s an expensive system, but Kelderman makes a complete rear-axle airbag suspension system that elimi-nates the leaf springs, a solution that could help soften the ride when needed. If the truck is your daily driver, when not towing you can reduce the rear-tire air pressure to soften the ride since full load-carrying pressure may not be needed when the truck is unloaded. Just be sure to reinflate the tires to specs when you hitch up again to tow.

Axle-Bearing Maintenance

Red letter QWe read the magazine each month, cover to cover. A while back you covered proper axle maintenance and whether the bearings really need to be redone each year. Mileage aside, the people I have asked gave about as many answers as there were people. Is there a definitive answer?

The factory would have probably done the best job of installing the bearings, and having service by an aftermarket dealer changes all of that. I have also heard that, if you don’t show evidence of said work and you have an accident due to an axle failure, insurance will not pay. In your experience, approximately how many miles do you feel can be driven before you need to replace the bearings?
Scott Pascoe | Santa Clarita, California

Green letter AMost axle manufacturers recommend 12 months or 12,000 miles as a standard inspection and repacking schedule for axles with conventional hubs and bearings. This includes axles fitted with Dexter E-Z Lube and Nev-R-Lube hubs. As for the axle manufacturer doing the best job with the original grease packing and installation, that would not be a significant factor in deciding to have the axles serviced. Any qualified shop that works on trailers can do a satisfactory job with a bearing inspection and repack, and it’s entirely doable yourself.

While the axle manufacturers suggest the 12,000-mile/12-month schedule for service, there is no set recommendation for complete bearing replacement. If you keep them serviced and don’t overload or abuse the bearings, they should last for many years but should be inspected annually for damage and wear. There have been some reported issues with foreign-sourced bearings, which further reinforces the need for annual service. As long as they look good, no problem. Fortunately, they are not that expensive to replace. Take care of your RV’s bearings and you won’t be “that guy” next to the highway with fried bearings, or worse, a broken spindle due to bearing failure and overheating.

Keeping your maintenance records concerning bearing service is a good idea in any circumstance and would likely position you in good stead during an accident investigation such as you described. Ask your insurance carrier directly about this if you’d like to set your mind at ease.

Hitch-Weight Ratings

Red letter QI own a 2011 Chevrolet Suburban 2500 with the integrated trailer-hitch receiver. The owner’s manual states the maximum WD trailer-hitch weight rating for the Suburban 2500 is 1,500 pounds. The label on the hitch receiver states the maximum WD rating is 1,000 pounds. RV forums are rife with opinions of which rating is correct, and apparently this is an issue with all 2007 to 2013 Suburbans. I can’t find any other information from GM on this rating issue.
Paul Malarik | Allendale, Michigan

Green letter AIf in doubt, Paul, go by the rating printed on the receiver label. The same applies to the rating on a tire’s sidewall, the axle tube, WD hitch hardware and so on. If it conflicts with the vehicle manual, go with the labels.

A vehicle owner’s manual is often published and printed well ahead of when the vehicle is rolling down the assembly line. Things can change between the time the manual publishing branch of the company receives its data and when the vehicle is built and placed in service. Certain vehicle basics are pretty consistent, such as how to unlatch the hood, switch on the heated seats or reset the clock’s time so it doesn’t drive you crazy with daylight saving time twice a year, but details such as tow ratings will vary depending on engine size, axle ratio, trim level and other factors. It’s difficult for the vehicle manufacturer to get all those figures right in a generic one-size-fits-all owner’s manual, given the time frames for printing a manual and assembling the parts.

A hitch receiver comes from an outside vendor such as Reese, Curt or another source. The vendor builds the receiver according to its contract with the vehicle manufacturer and places specification data on that product before it’s mounted on the vehicle either at the factory or as a dealer-installed option. Unless it’s a rare case of the wrong specification label being applied, go with the hardware label data, and you’re headed in the right direction.


TIP: Faded Front-Cap Cure

Fifth-wheel with vinyl wrap and oval sunset decal on front cap.I’ve been reading about faded fiberglass front caps in Trailer Life. We had the same problem with our 2014 Jayco Eagle HT. After checking into several places about repainting and getting quotes from $2,000 to $3,500, my son suggested we look into having it “wrapped” in vinyl, like they are doing to many vehicles today.

I took pictures of our Jayco and went to a company that deals in vinyl wraps of all types. I told the service person I would remove the decals and adhesive and sand the surface smooth to have it ready to wrap. He quoted me $500.

I removed the decals and adhesive, then wet-sanded the cap with 400-grit Wetordry sandpaper. The day prior to taking it to be wrapped, I removed the sealant at the molding where the cap attaches.

I took our fifth-wheel to the shop, and in about three hours it was wrapped in vinyl with a light color that is a near match to the original color. Since I was not able to obtain new decals from Jayco, I bought a decal to our liking from Amazon ($50), and the vinyl installer gladly applied that as well.

The looks of a faded cap were disappointing, but not to the point where I was going to pay thousands of dollars to get it repainted. However, $500 was reasonable, and we are very satisfied with the results.

I saved some money by prepping the cap myself (a heat gun or blow-dryer and a scraper worked well). The cap does have to be smooth before applying the vinyl. After the vinyl was installed, I resealed around the edges of the molding with a clear RV sealant.

I also briefly considered putting the vinyl on myself. After watching some YouTube videos on applying it, I decided against doing it. And after watching the installer put it on our Jayco, I was thankful I didn’t try it!

For less than $600, our fifth-wheel looks new again. We have gotten a lot of compliments on the vinyl wrap, and bugs (especially lovebugs) seem to come off easier than they did from the original cap.
Randy Ryman | Loris, South Carolina

Thank you so much for your detailed note explaining how you took care of your fifth-wheel’s faded fiberglass end-cap problem, Randy. Judging by our reader mail, premature fiberglass-cap fading and chalking are significant problems among owners.

There are vinyl-wrap companies all over the country, and a trailer owner should have little trouble locating one. The most significant question may be how long the vinyl will last under typical RV environmental exposure conditions. A local vinyl-wrap franchise of a national company told us to expect about a five-year useful life from a typical vinyl-wrap job, as long as the owner follows the company’s care and cleaning recommendations, such as no pressure- washer use. I’m sure your information will spark some reader interest.


Have a Tech Question?

Email [email protected] and include your full name and hometown. Selected letters will be answered in the monthly RV Clinic column, but time does not permit individual replies.


Man leaning over engine wearing blue shirtJeff 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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