Trailer Tire Information

Tire Maintenance

Air Pressure

Your trailer tires support the weight of your trailer and cargo, right? Well, they don't! It's the air pressure inside them that actually supports the weight. Maintaining sufficient air pressure is required if your trailer tires are to provide all of the handling, traction and durability of which they are capable.

However, you can't set trailer tire pressure...and then forget about it! Tire pressure has to be checked periodically to assure that the influences of time, changes in ambient temperatures or that a small tread puncture has caused it to change.

The tire pressure recommended in your owner's manual or on the tire information placard is the recommended "cold" tire inflation pressure. This means that it should be checked in the morning before you drive more than a few miles, or before rising ambient temperatures or the sun's radiant heat affects it.

Since air is a gas, it expands when heated and contracts when cooled. In most parts of North America, this makes fall and early winter months the most critical times to check inflation pressures...days are getting shorter...ambient temperatures are getting colder...and your tires' inflation pressure is going down!

The rule of thumb is for every 10° Fahrenheit change in air temperature, your tire's inflation pressure will change by about 1 psi (up with higher temperatures and down with lower).

In most parts of North America, the difference between average summer and winter temperatures is about -50° Fahrenheit which results in a potential "loss" of about 5 psi as winter's temperatures set in. And a 5 psi "loss" is enough to sacrifice handling, traction, and durability!

Additionally, the difference between cold nighttime temperatures and hot daytime temperatures in most parts of the country is about 20° Fahrenheit. This means that after setting tire pressures first thing in the morning, the trailer's tire pressures will be almost 2 psi higher when measured in the afternoon (if the vehicle was parked in the shade). While that is expected, the problem is when you set your vehicle's tire pressures in the heat of the day, their cold pressures will probably be 2 psi low the following morning.

And finally, if the vehicle is parked in the sun, the sun's radiant heat will artificially and temporarily increase tire pressures.

Add all of these together, and you can understand why the conditions in which you set your vehicle's tire pressures are almost as important as the fact that you do set it.

It's important to remember that your trailers's recommended tire pressure is its "cold" tire inflation pressure. It should be checked in the morning before you drive more than a few miles, or rising ambient temperatures or sun's radiant heat affects it.

And by the way, if you live in the North and park in an attached or heated garage you will "lose" pressure when you leave its warmth and venture into the real world outside during winter. Add 1 psi "cold" pressure tire pressure to compensate for each 10° Fahrenheit temperature difference between the temperature in the garage and outside.

Repairing Punctures

One of the last sights drivers want to see when they are getting ready to pull their trailer is a flat tire. They realize that in addition to the immediate inconvenience of having to install their spare tire, they will have to get the punctured tire repaired.

While almost any sharp object left on the road can cause a puncture, most are caused by small nails and screws which keeps them within the general guidelines which allow the repair of punctures in a tire's tread area of up to 1/4" in diameter. Repair of larger tread punctures and of punctures to the tire's shoulder and sidewall areas are not recommended.

There are three primary considerations when repairing a punctured tire. You need to evaluate the damage the object caused as it punctured the tire, reestablish an airtight seal of the tire's innerliner, and completely fill the path the object took through the tire.

Any repair done without removing the tire from the wheel is improper. Without inspecting the inside of the tire for hidden damage comes the risk of returning a weakened tire to service. Punctures in the tread area that looked repairable have revealed upon further investigation that the object that punctured the tire had been long enough to cut the tire's sidewall from the inside. Without dismounting the tire, the hidden damage would have been missed. Simply "plugging" a tire from the outside without removing the tire from the wheel is improper. (If a tire is punctured while off-roading far away from civilization and a spare tire isn't available, a plug may serve as a temporary low speed solution which must be replaced with a proper repair as soon as possible upon returning to the road.)

There are many different rubber compounds used in a tire. The tire's inner liner uses a special rubber compound that has the ability to better retain air. Once punctured, the inner liner must be cleaned, buffed, cemented, patched and coated to assure its ability to retain air has been restored. Since this can only be done from inside the tire, it's another reason that a "plug" only repair is improper.

Continuing to drive on a tire with a "slow" leak may allow moisture to seep around the object and into the tire. This will reduce the probability that the tire can be repaired properly because the moisture will ultimately reach the internal steel and fabric cords used to reinforce the tire and possibly cause rust and loss of strength. To assure reestablishing a water tight seal the injury must be "cleaned" with a specially designed cutting "drill" that removes rust and sizes the injury properly to accept the rubber "stem" of the patch. Cemented in place, the stem will vulcanize with the tire to help prevent moisture from reaching the tire's reinforcing cords from the outside.

How do you know which procedures a tire dealer uses? Ask them! But be aware that if they say that they can repair a tire in 10 minutes for under $10 dollars without removing it from the wheel, they aren't following the Rubber Manufacturer's Association procedures. A correctly done flat repair that follows the multi-step repair procedures will take approximately 30 minutes and probably cost around $20. Driving on an improperly repaired tire is dangerous because it can further damage the tire and/or allow its strength to deteriorate over time. An improperly repaired tire driven at high speeds may suddenly fail, causing loss of vehicle control. Additionally, the use of an innertube as a substitute for a proper repair generates additional heat and should not be considered.

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