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Are Your Tires Tired?

June 2, 2011 by · 1 Comment 


There are few events with a towable RV that can compare with the feeling of despair and helplessness that one has when sitting on the side of the road with a tire torn to shreds.

This event can ruin vacation plans, cause considerable damage to an RV, create unwanted endangerment to you and the RV from traffic, and be an extremely costly event when a new tire must be purchased on the spot.

You can improve the odds against having catastrophic tire failure on your towable by following some simple but often neglected tire care steps.

I do not profess to be an expert on tires.  But, after thirty something years of RV experience and tire research I can tell you what I have come to believe is the best information related to your RV tires.  The short version is, “Been there, done that”.

PLEASE, I do not want anyone to become offended by the following statement:

I have  noticed an increase in a seemingly lackadaisical attitude toward a towable’s tires by many campers – especially those of the younger generation.

Perhaps this is due to improved tire designs and a lower incident of tire failure on passenger vehicles? In any event, tires on a towable are different than a passenger vehicle  and require  extra special attention. They carry a heavier load and  receive more abuse – especially on the curb side.  Their cold pressures are higher and trouble on the road often goes unnoticed until it is too late to stop tire destruction.  You can pull a trailer with a low or even flat tire for miles and never know it – that is until it catches on fire and starts sending out smoke signals.

If you choose to follow the advice below I can assure you that your tire life and safety will be maximized. Of course, no one can predict road hazards that can shorten your tire’s life.  But, proper care and maintenance can surely reduce your chances of being stranded on the side of the road.

The number one cause of RV tire failure is improper inflation pressure.

Typical Tire Sidewall Script.

Inflation Pressure – Look at the sidewall of your tires.  The information molded into the rubber is gospel.  You might need a magnifying glass to read everything on the sidewall.  There you will find the maximum inflation pressure and maximum weight along with the statement COLD.  There is some confusion as to what is cold.  Cold is the air pressure in your tires after they have been sitting at least three hours out of the sun.  The best time to check cold pressure is in the morning.  Inflate your tires to the maximum pressure on the sidewall.  DO NOT run a lower pressure.  Tire pressure will raise as you drive and the daytime temperature increases.  The rise in pressure is OK and expected.  DO NOT let air out of your tires to adjust pressure unless they are cold as described above.

We once thought of air as free.  Unfortunately, this is no longer true.  Unlike inflating a passenger car tire to 32 psi, trailer tires – depending on their load range, can require up to 110 psi.  Finding clean, water free compressed air to handle high pressures can be a problem.  Besides, if you need to adjust COLD air pressure in the morning before pulling out, driving to an air station will heat the tires and make the inflation inaccurate.

High Volume - High Pressure 12 VDC Compressor

Compressed CO2 Tank and Kit from Lowe's

One solution is to invest in a GOOD 12 volt air compressor capable of reaching at least 150 psi.  A good one will cost you upwards of $100.  The cheap compressors overheat quickly and are prone to early failure.

An alternative to an air compressor is a pressurized cylinder of carbon dioxide.  Once you have purchased a cylinder as shown, you simply exchange an empty cylinder for another full one at a cost of about $8.00.  There is more than enough CO2 in the cylinder to increase the pressure on low tires multiple times.

Lastly, you can carry a portable air tank.  Fill it at a station or from a home air compressor.  The down side is they take up a lot of valuable space and are not of much value if you have tires that run over 60 psi.

150 PSI Gauge with flexible hose.

Purchase a quality air pressure gauge.  The little pencil gauges as used on cars are not adequate.  Gauges at air stations can be inaccurate.  A truck stop is a good place to purchase a quality gauge.

Cold air pressures lower than the maximum listed on the sidewall reduce the load carrying capacity of your tire.  Lower pressures will increase tire temperatures.  High tire temperatures can quickly destroy a tire.  Lower pressures also introduce more friction and reduce fuel economy.  Tire life may be drastically reduced by under inflation.

Tire System Technoligies TPS Monitor in our TV. Note pressure and temperature for right front tire.

What About Tire Pressure Monitoring Systems? – I use a TPMS from Truck System Technologies.  I cannot say that it is the best system since it is the only one that I have ever owned.  What I can say is I am extremely happy with my TPMS system and TST is a company that stands behind their products with excellent service and warranty replacements.  The monitor I have gives readouts of both pressure and temperature.  It will sound a warning alarm if tire pressure falls and can save a tire and even prevent an accident by allowing quick driver intervention.  I run sensors that simply screw on the valve stems on the truck tires as well as the four trailer tires (yes, that is 12 sensors).  The TST tire pressure monitoring system has become one of those things I won’t leave home without.  IMHO, it is a sensible investment in your safety on the road.  Give TST a call.  I believe you will find them extremely knowledgeable and helpful.

Exceeding a tire’s load rating ranks as the second most common cause for tire failure.

Tire Load Rating – You will find a load rating on the side of your tire.  Something like C, D, E or G.  While the load rating is important in selecting the proper tires for your RV, the actual weight rating for inflation pressure is what you want to look at.  Load ratings in pounds (or Kg) can vary considerably for a specific letter load range.  You should know what your trailer weighs and select tires that exceed your actual loaded weight.  Whenever possible, I select tires with the highest possible load range and weight rating that will fit my wheels.  Wheel/Tire fitment must consider the maximum pressure rating for the tire’s wheel.  Yes, wheels have pressure ratings too.  It is not a good idea to put a tire that is inflated to 110 psi on a wheel rated for 80 psi.

You should know what service your towable tires are rated for.

Tire Type – Passenger car P-Metric tires are NEVER suitable for any RV over 3,500 pounds fully loaded.  While towables may use LT (Light Truck) designated tires you are much better off purchasing tires with the ST rating.  ST is Special Trailer.  These tires have less tread for lower rolling resistance and heat build up, stiffer sidewalls and an additional UV and ozone protection compound in the sidewalls.  ST tires are only for trailer use and should not be used on trucks or motor homes.

First two numbers are the week, last two are the year the tire was built.

Old tires are not safe tires – even if they still have good tread depth.

Tire Age – The accepted lifespan of a RV tire is seven years.  This holds true even if you have good tread and barely visible sidewall cracking.  Deterioration has been taking place in the cord body of the tire and the adhesive holding individual plies together has eroded.  You can check the age of your tires by looking for the date stamp at the end of the DOT line.  If it is not visible on the outer sidewall, you will need to crawl under the RV to look at the inside sidewall.  It may read something like 2110 – this indicates the tire was manufactured during the 21st week of 2010.  If your RV tires do not have the date code, they are over seven years old and should be replaced.

Tire Inspection – Always inspect each tire before every trip.  Look for nails in the tread, cuts, bubbles in the sidewall and abrasions on the inner sidewall from the RV frame or shocks rubbing.  If you find a nail in the tread, understand that removing it may cause the tire to go flat.  Or, if the nail has not penetrated the inner casing of the tire, some cord plies may be damaged.  Best bet if you find a nail is drive to a tire store qualified to fix RV tires for inspection and possible repair.

Towable RV tires are NOT high speed rated tires.

Speed – RV tires are NOT speed rated like passenger car tires.  While your car can have tires rated for over 100 mph, your RV tires actually have a MAXIMUM speed rating of 65 mph.  Hopefully, no one will be pulling a towable RV over 65 mph – But if you are you are asking for trouble in more ways than one.  Slow Down!

Answers to some more common tire care questions.

To Cover or Not? – The answer is YES.  Whenever possible cover your RV tires to avoid damage from the sun.  I recently looked at a RV that had been parked so that the curbside faced the sun.  The street side had been shaded.  The tires on the sunny side had cracks in the sidewalls rendering them unsafe for highway towing.  The shady side tires still looked like new.

What About Tire Shine Chemicals? – If the tire shine contains any petroleum product the answer is NO.  If you do use a tire shine select one with a UV sunscreen (just like lotion for your skin).

Should I Balance and Rotate my Towable Tires? – Yes.  Balancing will increase tire life as will rotation every 5,000 miles max.

Do I Need a Spare Tire? – Definitely yes.  Buying a replacement tire on the side of the road can be super expensive.  The spare should be the same type and size as your road tires.  Don’t forget to check inflation pressure on the spare too.  A flat spare is not very useful.

Tire Twist in tight turn.

Can I Damage Tandem Trailer Tires in Tight Turns? – It is always best to avoid tight turns as they can cause undue sidewall stress.  This stress can break inner tire cords and cause unseen damage.  ST rated tires have stronger sidewalls for this very reason.

What About Emergency Road Service? – I have carried emergency road service for my RV since the early 90’s.  I can honestly say that none have made a profit off of my annual premiums.  Coverage from Good Sam or Coach Net has proven invaluable.  They will come and change a tire for your spare, repair a tire or tow you to a facility that can repair or replace a tire if you are disabled.  Annual coverage is normally about $10 a month – or the cost of two small combo meals at McDonalds.  Be sure your ERS will cover your particular RV – most automobile policies will not provide RV coverage.

What About Lug Nut Tightening or Torque? – Your wheels get hot from using your brakes.  The heat expands the wheel and will actually stretch the lug nut studs.  When they cool off, the lugs nuts can become loose.  Always re-torque wheels to proper specifications when remounting a wheel and again after about 100 miles of use.  If you descend a mountain grade and generate a lot of brake heat check your lug nut torque soon after the wheels cool.     A torque wrench to do this job can be purchased inexpensively from Harbor Freight Tools.  Don’t forget the right size deep well socket to fit your lug nuts.

What About Storage of a RV – What do I do with the tires? -  Clean them with soap and water.  Inflate them to the  proper pressure.  Park on a smooth, dry surface or use 2 x 8  pressure treated boards under the tires if parked  in a dirt or gravel area.  Cover the tires to protect them from sunlight.  With modern radial tires fear of “flat” spots from sitting is no longer a concern.

Tire prices are increasing (again!) as oil prices rise.  The tires on our fifth wheel trailer list for over $300 each – plus mounting, balancing and a disposal fee for an old tire.  It really pays to take car of your towable’s tires!



One Response to “Are Your Tires Tired?”
  1. butterbean carpenter says:

    Thank you, for a very informative article..

    Smooth roads & balmy breezes !!!!!!!!!

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