RV Builder Pumps Tires With Nitrogen--Should You?

It's a heady season for RV manufacturers: The great Recreational Vehicle Industry Association (RVIA) trade show is on in Louisville, and everybody wants to show off their stuff. Enter Dutchmen, the maker of fifth wheels and travel trailers by the same name. What's new in the Wooden Shoe? Nitrogen in your tires.

If you remember high school chemistry, you may remember our friend nitrogen, the gas that makes up the majority of earth's atmosphere. While 'plain old air' has been used for years to fill tires, the wrinkle a few years back was to fill tires subjected to a lot of stress with nitrogen. Think race car tires, jet aircraft, etcetera. Why nitrogen?

Plain old "air" molecules are about four times smaller than nitrogen. Because of that, rubber tires slowly "leak" air because the rubber is a bit permeable--the air slowly works its way through the tire pores, if you will. Since the nitrogen molecules are so much bigger, tires tend to lose pressure far more slowly. As a result, the tires run cooler and get better fuel economy. Sounds like "N-inflation" is a shoe in? Hang on, might it lead to a false sense of security? If you don't check your tire pressure as often, will you likewise fail to look your tires over for damage?

Tire permeation isn't the only reducer of tire pressure. Witness a statement from tire maker Michelin, "The existence of several other possible sources of leaks (tire/rim interface, valve, valve/rim interface and the wheel) prevents the guarantee of better pressure maintenance for individuals using nitrogen inflation." The company does not recommend nitrogen inflation, except, "in a high risk environment and/or when the user wants to reduce the consequences of a potential abnormal overheating of the tire-wheel assembly (for example in some aircraft applications)."

Notwithstanding, economics may come into play. A nitrogen tire "fill up," can cost you as much as $10 each. If you're somewhere where nitrogen is unavailable and have a low tire, you can "top off" the tire with ordinary air. But later you'll be advised to have the tire bled out and refilled with nitrogen.

Breathing a Little Fresh Air on Tire Longevity

RVers depend on their RV tires--and they're an expensive thing to replace. We've often talked about the matter of safety and RV tires, but this time will highlight finances and what you can do to cut costs.

Industry experts, including tire-consuming fleet folks--all agree: "The largest contributing factor [to a tire's life span]," says Pat Martindale, "is air pressure. It was years ago, and it still is today." Martindale is a maintenance guru for Penske Truck Leasing, and recently gave this maxim to Light & Medium Duty Truck magazine.

Similar views are echoed by Michelin North America through their customer engineering support manager, Doug Jones. Jones says that underinflated or overinflated tires simply wear unevenly and prematurely wear out. Underinflation can lead to zipper ruptures along the sidewall that lead to rapid deflation. As little as 10 pounds "under recommended pressure" can cause an increase in tire wear of 7 to 15 percent. Overinflate that big rubber roundie and you can look to see increased wear and tear on the center of the tire tread, a stiffer ride, and a lot less forgiveness when hitting 'road hazards.'

You dually runners, listen up: Pressure between two tires in a dual set should not differ by more than 5 pounds. If the difference is bigger than that, one tire will be larger than the other, and the smaller one won't roll nor deflect as it should.

Photo: kearnj on flickr.com

"Paint Your Wagon," Maybe, But Leave the Tires Alone

It's the kind of thing that might appeal to the Imelda Marcos among the RV set: Those nice tires we keep under our trailers, tow vehicles, or motorhomes. Everybody likes those "shoes" to look good. But how do you best do it?

A few days ago we heard about an RVer who was told one of the best ways to keep his rig's tires looking good was to give them a good "paint" of transmission fluid. Whoa! "Oh, yeah, shines 'em right up!" Maybe so, but it's an awful expensive exercise tire "makeup." Tires are pretty peculiar beasts, and like the man says, you've got an awful lot riding on them to be making mistakes. Painting your tires with transmission fluid is a definite way to wind up paying dearly. The oil in tranny fluid will cause them to rapidly deteriorate, with possible disastrous consequences.

OK, how about some of those nice silicon containing spray on potions? Years ago we were in the upholstery repair trade--fixing vinyl seats in restaurants and on car lots. A lot of folks got snookered into spraying "Armor All" on their seats. Made them shiny and slick, and it brought us a lot of business because the stuff dried the material out, and cracks are a result of drying out. Tires are somewhat the same: Tire makers put chemicals into their tires to keep them from drying out. Put oils or other chemicals on them to make 'em look nice, but counteract the internal chemicals, the tire dries out, cracks, and pretty soon they deteriorate.

We attended a training seminar at an Escapee's RV convention a couple of years back. The featured speaker was "retired from the tire industry." His advice? When you're sitting put in one place for a while, COVER the tires to keep the UV rays off them. Don't put ANYTHING on them to "treat them." If you don't like how they look, then wash them with soapy water and rinse them off. His years of insider experience taught the lesson, there's nothing on the market that you can spray on or paint on that will preserve them, and most will actually do harm.

Viking courtesy www.phillipmartin.info

Air Pressure Gauges: Dial Me Up or Stick it to Me?

We've often "lectured" on the necessity to caring properly for your tires. 'Take care of your tires and they'll take care of you!' has been our mantra. A major part of caring for those rubber donuts is making sure you've got sufficient air pressure. How do you test yours?

Some folks rely on "built in" gauge on the hose down at the gas station. You may have noticed that those gauges have been becoming fewer and fewer as the days roll along. And even when the hose does have a gauge, after having been slapped around like a TV wrestler, they tend to get a bit punch drunk and don't give reliable information.

Some folks like the "put it in your shirt pocket," "stick" style air gauge. They may have a point, but we've found the "stick" type aren't always accurate, and often have the drawback of having fewer "graduations," making it difficult to ensure what the pressure is within less than five pounds. Here's another case of spending a few more bucks, but spending it wisely. The "dial" type air gauges are more accurate, and usually read down to the precise pound of pressure.

If you spring for the dial style, do take good care of it. Dropping it on the pavement can cause irepairable damage. We carefully put ours away in the "glove box" (who--other than snobs maybe--drive with gloves these days?) when not in use.

How Old Izzat Tire? And What Does It Matter?

Those expensive 'rubber donuts' we put on our RVs are far too often, neglected. After all, there's not much "attractive" or sensual about tires. Emelda Marcos didn't keep a garage full of them, and tire showrooms are generally noisy places that offer popcorn, not caviar, to shoppers.

We've blogged about keeping a close eye on your tire pressure, but that's not the only concern. Keeping your RV tires "fresh" is just as important--and more easily overlooked. After all, when did you last change out your RV tires? I can't tell you when I did--I only remember it was because we had an alignment problem and scuffed a couple of the poor beggars to death.

The RVIA (Recreational Vehicle Industry Association) warns that RV tires, unlike car "shoes," generally don't wear out--they 'date out.' Because we put so few miles on them, our RV tires are more likely to die of UV radiation poisoning than from road wear. The RVIA says, "Statistics indicate that the average life of an RV tire is five to seven years." After that, you're living on borrowed time and living dangerously.

So how old are your tires? Here's a picture of a tire sidewall stamp:

The so-called "DOT Code" lists the information we need. The last 4 digits, 2104 in this case, tell us the tire was built in the 21st week (21) of 2004 (04). That dates this tire manufacture at sometime in the middle of May 2004--about three years old, plenty of "age" left in it for an RV tire.

But notice too, a bit of "weather checking" on the sidewall near the rim. Caused by heat, age, ozone exposure, and (believe it or not) exposure to petroleum tire dressings, "sidewall weathering" can weaken the tire and your safety. If these cracks are more than 2/32" deep, replace the tire. And lay off the use of "tire dressings." They may make the tire shiny, but they'll eat up your investment.