Monday, October 22, 2012

Tire Difficulties

Recently there have been several blogs written about mishaps with RV tires.  Generally the bloggers have indicated that the tire "blew out" while driving and sometimes caused significant damage to their RV.  While a manufacturer defect is always a possibility there are several other reasons that a tire might blow out.

Curbing the tire occurs when you pull up to a curb to park and you unintentionally scuff the sidewall against the curb.  Depending on the speed and angle , you can damage a tire enough to cause overheating and separation within the plys of the tire.  Later down the road bulges may appear on the sidewall indicating an internal issue leading to a "blow out".

Road hazards or running over something or backing into something.  Significant damage can be done to the infrastructure of a tire if this occurs and it can lead to a "blow out".  After hitting something, even a pothole, tires should be throughly inspected and may even require being removed from the wheel to ensure there is no damage.

Speed most RV tires are not designed with speed in mind, they are designed for speeds of 65 mph or less.   Tires run at higher speeds have significant heat build up which can cause sidewall separation and a nasty "blow out".

Alignment is the relationship of the tire to the frame as you roll down the road and yes, the alignment can be off on a trailer.  One example would be a single wheel that has been curbed at a relatively low speed but causing the axle holding the wheel to bend slightly.  Another example, would be the frame shifting on the leaf springs causing a sideways pull as you ride down the road.  Both of these conditions and several others can cause tires to overheat and (wait for it)  "blow out".

Extreme climate or temperature can cause conditions within the tire to cause a "blow out".

Underinflation is likely one of the biggest causes of the "blow out".  When was the last time you had your rig weighed, fully loaded with water, propane, vegetables and the like?  Empty trailers require less air pressure that fully loaded trailers.  How do you know how much air to put in the tires unless your weigh your rig in travel condition?  You don't know.  Manufacturers supply tons of information regarding the amount of air pressure required for different size tires under different load conditions.  You need to be fully aware of these so you can make safe decisions before you hit the road.  Michelin has a chart that I have found to be very helpful over the years.  Notice that the weight bearing down on the tire is very important.  As you load the vehicle you must compensate with more air in each load bearing tire.  You can download a copy of the chart or look up your tire size at

I recommend strongly that you begin at the beginning and if your trailer is more than a couple of years old, have the alignment checked.  Once you are sure of the alignment, load the trailer with all the stuff you plan to take with you and go weigh it.  Determine from Michelin's chart what your required air pressure is based on the tire size and load.  Then inspect your tires daily.  Once in the morning when you leave for a trip and often at each stop on your trip.  Feel the wheel and tire.  There should not be any extreme heat build up.  If there is look for the cause.  Even a dragging brake can cause heat build up in the wheel and lead to a "blow out" if you don't catch it.  Watch the sidewalls for bulges or cracks of more than 2/32".  Replace tires with these issues.  If you have a flat, pull over and seek help changing it.  Never drive any distance without all of your tires in good working order and on the ground.  Driving with one tire damaged requires the other tires to take up the load and can cause them to overheat, leading to ply separation and "blow out".

Don't forget the tow vehicle.  As you load it down the rear tires require more air just like the RV.

And enjoy your trip.

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