Why you need tire pressure monitoring

Roslyn B. says, “I have a question about trailer tires. This past weekend I had a blowout on a busy interstate. We spent two hours in 102 degrees in a precarious position waiting for the emergency assistance from Good Sam to get to us. Thankfully a FHP trooper waited with us hoping to slow the traffic speeding by on I-275.

We had the tires on my 19-foot Airstream checked out prior to our trip. The tire was only two years old. Any thoughts on what to do to prevent this from happening again? We keep it stored in an inside facility in Orlando.”

We feel you, Roslyn. A tire pressure monitoring system that allows you keep track of your tire performance might be your best option. When installed, a remote monitor in your tow vehicle tells you when a tire becomes dangerously under- or over-inflated.

Tire pressure monitors are quickly becoming a necessity rather than the newest gadget out in electronics land. Every new passenger vehicle and light truck produced or sold in America has a TPMS system for good reasons.

People are fast becoming believers, due to the fact that they’re hearing stories from other RVers or that they’ve had a near disaster or worse and experienced tire failures themselves. To most folks, TPMS systems seem complicated and difficult to understand, so we’ll try to give a “non-geek” explanation of how they work. They really aren’t that complicated or mysterious.

Tire Pressure Monitoring Sensor

First, these systems are completely wireless. This means that they have no wires running from the sensors to the monitor installed on the driver’s side dashboard area. They operate on frequencies that allow them to communicate back and forth from the sensors to the monitor. The system is constantly requesting the temperature and pressure from each sensor installed on every tire on the vehicle.

When the sensor is ‘asked’, it responds with an answer, giving the monitor the data and then displaying that information on the screen for the operator to see. Settings are established in advance so that the system understands what the high and low pressure and high temperature settings are supposed to be. As long as the tire stays within those setting parameters, the system remains quiet and displays that all is well.

If, however, the system detects tire anomalies (a fancy engineering word for ‘the system is out of established limits’), the monitor immediately goes into an alert mode, and lights and sirens go off to give the driver the opportunity to make quick educated decisions about the issue before it becomes critical.

If a nail or screw is picked up in a tire, a brake begins to drag, or a hub bearing fails, these (and other issues) can cause air pressure, the lack of pressure, or even heat to become a problem. The system immediately jumps to the problem tire or tires, and lets the driver know exactly which tire is in trouble—possibly preventing a catastrophic event.

Tire Pressure Monitoring Sensor

Sometimes the TPMS doesn’t alert the driver to a blowout in advance of it occurring, for a simple reason: if there is a catastrophic occurrence that takes place instantly—such as hitting a piece of debris or a very sharp-edged pothole—the tire fails instantly and there’s no way that the system can tell the driver ahead of time that that’s about to happen.

In any case, keep vigilant and make sure you are not driving on old tires. (The date of manufacture may be much older than the purchase date.) Make sure that you have your tires properly inflated, and weigh your trailer at a truck scale to make sure it’s not overloaded.

The TST tire pressure monitoring system is available in the Airstream Life Store.

Tire Tips—Part 1

“Your tires do a big job, and they don’t ask much of you in return,” writes Rich Luhr, publisher of Airstream Life magazine and author of the new Airstream Life’s (Nearly) Complete Guide to Airstream Maintenance. “Just keep them inflated, inspect them periodically, and replace them when they get too old or worn.”

Luhr and other Airstream experts share their top tips about trailer tires in this and the next issue of Outside Interests.

Tire pressure: the magic pill

What’s the easiest way to better your ride, decrease your tire wear, and improve braking and road handling? “Correct your tire pressure,” said Jon Gold, presenter of a safety lecture during a recent Alumaevent.

Tire inflation illustration
“You want your tire to look like the one in the middle of this diagram,” said safety presenter Jon Gold.

“When you’re under-inflated, you’re riding on your sidewalls, the thinnest part of your tires,” explained Gold. “You’re asking for a blowout.” The optimum tire pressure for your Airstream is hidden in plain sight on the side of your coach, on a metal plate.

“Typically that number is either 50 or 65 psi,” writes Luhr in his maintenance guide. “The tire pressure should reflect the loaded weight of the trailer.” If your Airstream rolls on factory-issued Goodyear Marathon ST (Special Trailer) tires, see Goodyear’s Load/Inflation tables online to determine the right psi. Incorrect pressure can cause uneven wear and other problems—some severe.

Invest in a good tire pressure gauge,

and use it before every trip (and after you set out on the road again after camping for awhile). “Buy a good brass gauge with a short piece of hose,” advises John Irwin, Airstreamer and contributor to Airstream Life magazine. “That makes it easier to get it on the valve stem without losing a lot of air in the tire.”

“Keep the gauge with your trailer tools, along with a 12-volt DC air pump with an extension cord,” suggests Luhr. “It’s a nuisance trying to find an air pump at a gas station when you need a top-up, and often difficult to get close enough to it with your trailer. Having an AC-powered air compressor at home is a convenience, too.”

Consider a tire pressure monitoring system

Keep track of your tire inflation with a TPMS. “These systems typically use sensors screwed onto the valve stems, or placed inside the wheel,” explained Luhr. “A remote monitor in the tow vehicle will alert you if the tire becomes dangerously under-inflated, or over-inflated, usually from overheating of the brake or wheel bearing parts.”

“You want to know what’s going on with your tires because often you won’t feel or see a change in tire air pressure. On multi-axle Airstreams it’s even possible to lose a wheel entirely and not feel any change in towing characteristics,” he said.

Knowing immediately what’s going on can save you a lot of trouble. Buy a quality TPMS; “this is a case where you’ll get what you paid for,” said Luhr.

Installing a TPMS means you’ll know the pressure of each tire moments after you get in your tow vehicle, every time you tow. “No more bending down and checking each tire one at a time, no more getting your hands dirty, and less time spent getting ready to tow,” Luhr said. “Don’t forget to buy a spare monitor for the spare tire, so you don’t have to slide under the Airstream to check it before every trip.”

“Tire monitoring systems will catch most threats in most cases,” said Irwin. Owner of several Airstreams and other trailer models through the years, he offers this tip: “When underway, and you’re stopped at a stop light, reach over and punch through all the tires in the system, and look for any tire that doesn’t match the others. If one is very high and hot, something’s wrong. If one is low, you could have a slow leak, or worse.” Keep in mind that pressure varies with the temperature of the environment—it climbs when tires get hot, and drops as tires cool. “The sunny side can be higher than the shady side,” Irwin said.

When and how often to check pressure and inflate?

Because of temperature changes and normal leakage (losing one to two psi a month is expected) check your tire pressure once a month. During a trip, check them weekly.

There’s no need to remove air when tire pressure increases during the day, and don’t stress out about temporary altitude changes, (such as heading up the hill for a day of skiing)—the correct pressure is the one you put in when your tires are cool before you start your day of driving. If you move to a new campsite with a significantly different altitude, adjust your tire pressure the following morning.

Do a walkaround and look for signs of trouble whenever you inflate. “Check your tires for bulges,” said Irwin. “Does it look like a bicycle tire? If it’s round, the pressure could be way too high, or it could be a slipped belt.” Check for thrown (delaminated) treads, bulges in the tread, isolated worn patches, and rapid wear in an isolated area.

Want more?  Read Part 2 by clicking here!