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RV Q&A: Tire-to-Tire Gap

Originally Published in Trailer Life Magazine

Red letter Q
I have a question regarding the safe distance (gap) between fifth-wheel RV tires. I’ve looked at various tandem-axle trailers, and the distance between the tires varies. The distance between our fifth-wheel tires is about 1½ inches, and that seems to be too close together.

Our RV is a 2015 Redwood 38RL that we purchased in February 2016. It is a beautiful, spacious trailer that my wife and I enjoy very much. We had an issue last December when a bolt came out of the undercarriage, causing extensive damage that required the replacement of the rear axle, a portion of the frame and all four tires.

I don’t recall how close together the tires were prior to the repairs, but now they seem too close. Should I be concerned?

Robert Lorbeer | Prescott, Arizona

Green letter A“A miss is as good as a mile,” Robert, and as long as your RV’s tires don’t show any evidence of contact-related damage, you’re good. There are different tire-to-tire spacings because there are many different tire sizes and suspension configurations in use on different size and model trailers.

A trailer suspension primarily allows a tire to move vertically with the suspension travel, but there’s also a small amount of fore-and-aft movement that takes place. However, there’s not enough fore-and-aft movement to cause tires to rub when they’re 1½ inches apart at rest.

If a suspension were so worn out that it allowed that much flopping around, it would need some serious repair, and it’s likely the tires would be failing because they’d be seriously out of alignment.

Make sure the shackles and other components are in good shape, and your setup is probably fine.


More Tire Clearance

Red letter Q
I have a 34-foot Keystone Tailgator toy hauler with only 2 to 3 inches of clearance between the fifth-wheel’s tires and the top of the fender well. The tires were rubbing the top, and the factory had left a screw above the rear tires on both sides. On the right side, the screw punctured the tire, and the tire shredded on a recent trip.

When I figured this out, I had my springs put on top of the axles instead of under them. This raised the trailer about 5½ inches. The sewer dump was also very low, and the front of the trailer was high when hooked to my truck. This fixed all of that.

What is your opinion on having this done? It cost me only $432.

Roger Meacham | San Angelo, Texas

Green letter AThat seems like a pretty good pricing deal, Roger, and the clearance-problem solution should work well. Doing a spring and axle flip is a solid, reliable way to raise the trailer a few inches. Some people express concern that this may make a trailer less stable, but in fact it would take a much greater lift to adversely affect handling. A few inches will raise the rig’s center of gravity a bit, but not enough to cause any harm, unless you’re in the habit of speeding around corners, for example.


Exterior Polish

Red letter Q
I read Marlyn Demeter’s “Fiberglass Cleanup Redux” letter in July’s RV Clinic about repairing the finish on the front end of a trailer. My brother-in-law used a product on the sides of his motorhome. It looked great, so I tried some on the front of our fifth-wheel, which is exposed to the sun from dawn to 3 p.m. daily. Wow, it looks like new. It was designed for boats but works on fiberglass RVs. The product is Poli Glow, and it can be ordered at 800-922-5013 or on www.poliglow-int.com. I hope this helps.

David Rayles | Vevay, Indiana

Green letter AThank you for the recommendation, David. There are a number of good products for restoring an RV’s fiberglass finish on the market, and it’s good to hear that Poli Glow worked for you. We’re passing this on to our readers, as some may find it very useful.

Half-Ton Towing by the Numbers

Red letter Q
I read September’s “Half-Ton Towables” article on fifth-wheel towing with a full-size pickup. I have a 2014 Toyota Tundra and tow a 2013 28-foot Palomino Puma.

I have had the truck and trailer weighed with my wife and me in the truck and the trailer loaded for a trip. The truck weighs 5,220 pounds, and the trailer was weighed separately at 8,460 pounds. Dry weight on the sticker for the trailer is 6,922 pounds, and cargo capacity is 2,871 pounds.

If I add the empty weight of the trailer and the cargo weight, that comes to 9,793 pounds. According to Toyota’s owner’s guide, the truck will pull 12,300 pounds in the bed.

Is the weight of the truck included in that total towing capacity from the manufacturer, or is it just the weight of the trailer? The tongue weighs 1,086 pounds.

This has nothing to do with towing weight, but the brakes Toyota put on the Tundra did not hold up, even though I have the towing package. Toyota replaced two sets of front brake pads under warranty. I have since changed all four wheels to Power Stop rotors and pads.

Bill Allender | North Hills, California

Green letter AWe address the matter of how to use the gross vehicle weight rating (gvwr), gross axle weight rating (gawr), gross combination weight rating (gcwr) and other figures relating to setting up or analyzing a tow rig and trailer combination on a regular basis in these pages and on our website. The question keeps arising, so we’ll take another shot at it here.

First, you didn’t provide body style, engine, axle ratio and other pertinent towing information, so some of our figures will be approximate, based on Toyota’s 2014 Tundra published information. Your truck is rated for a maximum tow rating of 10,400 pounds and ranges down to 9,000 pounds, based on the variables mentioned above.

To determine the true towing capacity for your truck, you’ll need to deduct the weight of the truck, passengers, accessories, fuel and cargo from the gcwr, which could be as much as 16,000 pounds, depending on factory equipment. If your truck has the highest gcwr, you should be in good shape regarding your trailer’s 8,460-pound weight.

Regarding your frequent brake-pad replacement, we haven’t heard any other reader reports of this situation, so it doesn’t seem to be a significant problem with Tundra trucks. If the brake control is not adjusted properly, the trailer will not do its share of braking and that could cause premature pad wear. This is also dangerous, because in an emergency you won’t have the full potential trailer braking to stop the combo.

I’d recommend taking the truck and trailer to a service center to check the brake-control adjustment and inspect the trailer brakes for proper operation. This may well eliminate
or significantly reduce premature brake wear.


Jeff JohnstonRV ClinicRV DIYRV TechTrailer Life RV ClinicTravel Trailer How Tos

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