Intended Use

One key difference we need to think about though is the intended use.  An automotive tire (if you listen to the vehicle manufacturers) is there to give you a soft comfortable ride.  To do this they have lower air pressure and softer side walls which flex a lot.  How many of us learned to keep 32 psi in the tires?

Trailer tires on the other hand are meant to carry a load, your pop-up.  If we follow the 32 psi rule, the trailer tires side wall will flex too much and quickly overheat, possibility leading to a tire failure. More on tire pressure is a little further on.

Tire Construction

A big difference however lies in construction of the tires. There is a huge difference in the plies and belting of automotive tires versus many trailer tires. There is also a huge difference in trailer tire between manufacturer's and some are just down right garbage! In trailer tire world, Duro is like Michelin is to automotive tires... For example, Duros bias-construction tires are actually designed to meet light truck standards and exceed trailer manufacturer's requirements by far! They are even constructed with 4-6 plies for strength and puncture resistance! Most other trailer tire manufacturer's can't claim this.

Tire Pressure

The weight carrying capacity of your tires is computed with the tire inflated to the max pressure.  Look on the sidewall of the tire and you will see something like "Capacity 1068 Lbs at 50 PSI". This should be measured COLD (before you tow the trailer) and you should always use a quality pressure gauge to check tire pressure.  If you do check the pressure while the tire is hot understand that the pressure will rise, so 50 psi cold may be 60 psi after a few hours on a Texas highway.  DO NOT bleed air pressure out in this situation.  The tire is designed for this to happen.

For some interesting information on how the load carrying capacity can change when under inflated, check out the Goodyear Load and Inflation Information Chart for RV Tires.  Note that this chart is intended for use with Goodyear tires, but will give you an idea of the drop in load carrying capacity with under inflated tires.

Check the pressure every day before you tow. It's cheep insurance.  While you are bending down why not check the lug nuts at the same time.  It is recommended that you use a torque wrench to tighten the nuts to the correct setting. 
Then recheck after driving 50 miles, 250 miles, 500 miles, or before every trip as they tend to loosen up as they seat with the rim.

Tire Maintenance

Rot, UV damage, flat spots are of equal concern for any tire regardless of application - difference is in usage/application, construction, and care.

Say you have a vintage roadster or classic car stored exactly like a pop up outdoors exposed to the elements (who would, but this is hypothetical) and stationary for long periods of time, what do you think the tires would look like? A very key difference is exposure time to the sun and intensity of the suns rays. A automobile is used often and therefore you're always moving it about so the tires aren't exposed at the same times, intensities, etc. Now picture your trailer in the same place for months on end getting daily doses of UV. Great examples of this are the trailers where one side facing the sun all the time and the other is in the shadows. The tire on the sun sides is browned and cracked while the shaded side looks new. Follow me?

Another factor is how we care for the tires. Those that are neglected will show it, and those cared for with the wrong products are just as bad as neglected tires! For example, tires should never be cleaned with Spray Nine, 409, Fantastic, and most other household cleaners, nor should they be cleaned with 2/3rds of the products on automotive store shelves!!! Many of those cleaners are tough on the plasticizers in the tire compounds and break them down at an accelerated pace shortening tire life. This holds equally true for tire dressings! Most popular brands are BAD NEWS unfortunately to the ignorance of the public. Anything petroleum-based is BAD. 

Tire manufacturers also use waxes (both synthetic and petrochemical-based) to protect the tire polymer compounds against ozone. Regular usage of tires keeps the protective waxes at the tire surface where they form a physical barrier between the air (which has concentrations of ozone) and the tire polymer. When tires are not regularly used (a parked trailer, “garage queen”, even a lawn tractor), the wax subsides into the polymer matrix – i.e., it no longer stays at the near surface. So, ozone begins eating away any thin residual of the protective wax quickly, and before long, reaches the tire polymer and begin to break it down (this is why even tires that have been dismounted and stored in a garage or basement will still rot, although more slowly). Now at the same time, carbon black, which is the UV protectant for tire polymers, has lost its ability to protect against
UV radiation at the tire surface. So, with both ozone and UV radiations acting on the tire compounds at the same time, severe levels of degradation initiate. Thus, the tire “dry rots” and exhibits the telltale signs in the form of sidewall cracking.

Now to expand a little more on how so-called “cleaners and protectants” can actually act as degradants to PROMOTE more rapid deterioration of the tire… Many household cleaners (those mentioned and more) and so-called “tire cleaners” available in quantity at the auto parts store actually contain grease-fighting chemicals as well as very caustic chemicals (to remove brake dust residuals). These very chemicals WILL remove the protective waxes from the tires and also negatively impact the polymer plasticizers, which
results in more rapid promotion of deterioration!  Also, most popular tire dressings are petroleum or silicone-based (base stock) for the glossy or “wet” look and to provide an easy and even application. Basically, these base stocks are BOTH solvents for the
protective waxes and plasticizers and increase the rate of degradation too!!! In addition, most of the popular parts store “protectants” and “tire dressings” more often than not DO NOT contain UV stabilizers, which act as sun-screen for your tires! 

I actually find it amusing how the companies that manufacturer the cleaners, protectants, and dressings know this all very well, but instead supply products based on the demand of aesthetics and not the science…   Also, another thing that might get your attention is
how tire manufacturers often view this… In cases of so-called warranty sidewall failure, one of the first things tire manufacturers look for is evidence of the use of these types of products. In fact, there is a very simple test to determine their presence and EVERY
tire manufacturers has the test apparatus in the quality assurance/quality control laboratory. Anyway, if evidence of these products is found, this is often basis for not honoring the warranty because if you ever read the fine-print of a tire’s warranty you will
find this very clause where they will either tell you no products whatsoever or explicitly describe products that are useable….    If you think I’m wrong, do a little research on the web and look at the tire manufacturer’s websites and conditions of their warrantees!

Safe cleaners are quality car wash soaps (Meguiars or Mothers) or Eihman Fabrik High-Intensity Cleaner and dressings such as 303 Aerospace Protectant and Eihman Fabrik Black Opal Dressing. Every RV store I've ever walked into carries Meguiars and Mothers car washes and 303. Dressing tires that are stored for long periods is an absolute must! 

Storage

When storing your pop-up for long periods of time (like over the winter) try to move it on a regular basis to avoid getting "flat spots" where the tire contacts the ground.  If possible, set the trailer on blocks (follow your manufacturers recommendations for jacking/blocking) and reduce the air pressure in the tires.  Some people even remove the tires and bring them indoors for the winter.  If you do leave them out side, try to cover them to reduce damage from the UV rays of the sun.

Tire Replacement

Remember, a trailer tire may need to be replaced long before the tread wears out.  Generally rot or UV damage will be the death of the tire long before the tread wears out.  Maintain them properly and keep a good eye on them for signs of dry rot like side wall cracking. While I had originally planned to replace mine around age 4 - (long before I thought they would become a problem) I actually had to replace them after the second season.  Upon close inspection mine started to develop severe cracking/splitting in the bottom of the treads.

Trailer tires are available as just a tire or in a tire-rim sets.  If your current rims are rusted, go for the sets.  When you replace them make sure you get at least the same load rating or higher.  If you do buy a higher rated tire don't automatically assume you can pack more stuff in your camper.  The tires are only one part of the system which determines the capacity of the trailer.

Another idea when purchasing new tires is to get tire-rims sets the first time you replace, no matter what the condition of the rims.  This then gives you a second (older) set of tires & rims that you can put on the pop up for winter storage, keeping the good tires for travel only.

When you replace your tires remember the spare!

Basic Rules

• Always inflate the tires to the pressure indicated on the sidewall, check it every day of towing.
• Tow the trailer level when both the tow vehicle and trailer are loaded for camping.
•  Don't overload the trailer axle. This requires knowing the axle rating and weighing the trailer.

For an explanation on changing a flat tire, click here 

My thanks to  Bob Scott, P.E. - Geotechnical Engineer, as well as other members of the Pop Up Times Message Board for information on this page.

Recreational Vehicle Tire Care and Safety Guide