Before you go to the scales identify the Gross Vehicle Weight Rating (GVWR), Gross Axle Weight Rating (GAWR) for each axle, and the information about the correct tire and rim sizes and recommended cold tire inflation pressures for all vehicles and / or trailers you are going to weigh. Get this information from the Federal Data plate and RVIA Data plates we discussed earlier. Take this guide on how to weigh your travel trailer or RV with you and simply follow the steps in the charts that pertain to your configuration and fill in the blanks.

If any overload condition exists it must be resolved immediately. In some cases it might be possible to redistribute the weight and then weigh it again. If the overload condition still exists you'll need to remove some weight from the RV.

Just like the axles your tires and wheels have load ratings too. The maximum ratings are molded into the side of the tires. Keep in mind these are maximum ratings. The sidewall of the tire shows the maximum load and the minimum inflation pressure for that load. Never set the inflation pressures below the recommendations you find on the vehicle manufacturers placard and do not exceed the maximum inflation pressure ratings found on the tires sidewall.

The actual permissible load for a tire depends on the tire size and load range. The maximum load amount is molded into the side wall of the tire. You could increase your load capacity by changing to a higher load rated tire of the same size at a higher pressure, but keep in mind you still must not exceed the gross axle weight rating of the vehicle and you can't exceed the maximum tire inflation for the wheels. It's also possible in some cases to increase tire load capacity by increasing the inflation pressure in your tires, but you cannot exceed the maximum pressure specified for that tire. Consult your tire dealer for load and inflation tables.

It's also important that you use the same inflation pressure on both ends of each axle. If you weigh the RV and axle end loads differ enough that the tables specify different inflation pressures for each axle end, the axle is out of balance and you need to redistribute the load. If for some reason you cannot redistribute the load you must inflate the tires on both ends to the pressure required for the axle end with the heavier load.

Never operate your vehicle with tires inflated to less pressure than required for the load. Never operate your vehicle with tires inflated to less pressure than specified on the vehicle placard, no matter what the load. Never inflate your tires above the maximum pressure shown on their sidewalls

This would be a good time to discuss some of the leading causes of premature tire failure?

• Overloading the tires
• Under inflated tires
• Ozone and UV rays
• Age of the tires
• Rotating tires

The tires on your RV are the most vulnerable component affected by overloading the RV. There are numerous reasons for this. First and foremost is when the tires are not inflated properly for the load. Failure to maintain correct tire pressure can result in fast tread wear, uneven wear, poor handling, and excessive heat build up, which can lead to tire failure. Another problem is when you weigh your RV the total weight of the axles may be within the axles weight rating but it may be overloaded on one side of the axle or the other. This is a common problem with RVs and many times the cause is poor weight distribution and / or improper loading of the RV. When this happens the tire or tires on the end of the axle that is overloaded are subject to tire failure. When a tire fails many RVers contribute it to a defect in the tire, but that is rarely the reason. The only way to avoid this is to weigh each axle end separately to determine if a tire overload condition exists. The maximum load on each axle end is half the GAWR for that axle. If an axle end has dual tires, the load on each tire is half the load on the axle end. Never exceed the maximum tire load rating that is molded into the tires sidewall (along with the inflation pressure for that load).

Another leading cause of tire failure is under inflated tires. The load rating for a tire is only accurate if the tire is properly inflated. Under inflated tires cause extreme heat build up that leads to tire failure. The appearance of the tire can look normal but the internal damage is not visible and the tire can fail at any time without warning. If you find any tire 20 percent or more below the correct inflation pressure have it removed, demounted and inspected. Driving on a tire that is 20 percent or more under inflated can cause serious, permanent damage to the tire that may not be visible. Tires with internal damage from under inflation can fail catastrophically without warning.

Tires can lose up to two pounds of air pressure per month. If you don't check your tires for three or four months they could be seriously under inflated. Ideally you should check tire inflation, and adjust it if required, everyday that you move or drive your RV. If you can't get into the habit of doing it on a daily basis you need to make it a point to check all tires weekly at a minimum when you're traveling. You always want to check the tires when they are cold, meaning that you don't drive or move the RV before checking inflation pressure.

The only way to correctly measure the inflation pressure in your tires is with a quality inflation pressure gauge. Using your boot, a billie club or a hammer is not a quality pressure gauge, and don't ever depend on your eyes to check tire inflation. There can be as much as 20 PSI difference between tires that look the same. You need to invest in an accurate inflation pressure gauge. You should get one with a double, angled foot. This makes it much easier to check the outer tire of a dual set.

Wipe off the valve stem before you remove cap. The valve stem caps should be metal with an inner rubber gasket. A good cap will provide a seal even when the valve doesn't. Plastic caps may not provide a good seal at higher inflation pressures used on RV tires. Check all of your tires and adjust the pressure according to the manufacturer's recommendation. Never set the inflation pressures below the recommendations you find on the vehicle manufacturers placard and do not exceed the maximum inflation pressure ratings found on the tires sidewall. Over inflated tires are more likely to be cut, punctured or broken by sudden impact if they hit an obstacle, like a pothole, at high speeds.

Never check inflation pressure when the tires are hot. You'll get a higher-pressure reading and if you let some air out they'll be under inflated when they are cold. If you have dual wheels you'll want to add extension hoses to the valve stems to make the job of checking tire inflation easier. It can be nearly impossible to check the inner dual without extension hoses. The best extension hoses will have stainless steel reinforcement and external braiding for long trouble-free life. Make sure the ends of the hoses are securely attached to the wheels. If you add extension hoses you need to replace the rubber valve stems with all steel valve stems. The added weight of the extension hoses can cause rubber stems to leak air resulting in under inflation.

Ozone in the air and UV rays from the sun shorten the life of your tires. It's not uncommon to see RV tires with low mileage and plenty of tread that are ruined by the damaging effects of ozone and UV rays. Ozone in the air causes tires to dry rot and deteriorate. UV rays from the sun make it happen quicker. This is especially true of the tires sidewall. Inspect your tires for checking or cracks in the sidewalls. If you notice any damage have the tires inspected by a professional. There are basically two ways to protect your tires from these elements. Keep the tires covered with covers that will block out the sunlight when not in use. For long-term storage remove the tires and store them in a cool dry place away from the sunlight, and away from grease, oil, and fuel. I also recommend that you place something like a piece of wood between the ground and the tires. Be sure that whatever you use is larger then the footprint of the tire. No portion of the tire should hang over the edge of the tire block. This can cause internal damage to the tire.

The age of your tires is another factor that contributes to tire failure. I learned this lesson the hard way. I bought an early model Jeep CJ7 to tow behind our motor home. After completely restoring it we were ready to try it out. The tires on the Jeep looked new. There were no visible signs of damage from the sun and the tread looked as though they were used very little. We towed the Jeep from North Carolina to Florida and from there to Colorado and back to North Carolina with no problems. Shortly after that we towed it to Pennsylvania. Two hundred miles into the trip a front tire blew out, damaging the inner fender, shock absorber and an area below the door. I replaced the tire with the spare and within another 100 miles the spare blew out resulting in more damage. After getting a new tire and going back to pick the Jeep up along side the Interstate we took it to a tire store to have the remainder of the tires replaced. The technician came in and explained that the tires were nine years old and even though they looked to be in good shape they could not handle the stress put on them. He also explained that all tires manufactured in the United States have a DOT number. The DOT number on my tires was on the inside sidewalls. The last three or four digits in the DOT number identify how old the tire is. Older tires used three digits. The first two identify the week of the year that the tire was built and the third identifies the year. Newer tires use four digits. Again the first two digits are the week of the year and the last two identify the year. For example 3204 is the 32^nd week of the year and 04 is the year 2004. If you question the age of your tires, especially on a used RV, and you can't find the DOT number have them inspected by a qualified tire center.

Have you ever owned a vehicle and neglected to have the tires rotated and one day you suddenly notice that the front tires are wore out but the rear tires look fine? I'm sure that this has happened to most of us until we learned the valuable and expensive lesson of not rotating our tires. If one tire shows signs of wear faster than another tire it may be a signal that something other than normal tire wear is happening and you should have it checked. But if it's just normal tire wear you can even out the wear and extend the life of your tires by having the tires rotated on a regular basis. Talk to your tire dealer about proper tire rotation intervals.

Occasionally washing your tires with soap and water is OK, but anything beyond that can actually shorten the life of your tires. Sidewall rubber contains antioxidants and anti-ozones that are designed to work their way to the surface of the rubber to protect it. Washing tires excessively removes these protective compounds and can age tire prematurely. The same is true of most tire dressing designed to make your tires shine.

Always keep in mind that weighing your RV is a snapshot in time. Weights can and do change according to how you load and distribute the weight in your RV and on many other factors. You should get in the practice of weighing your RV periodically to stay within all weight ratings, and remember, whenever an overload condition exists resolve the problem before using your RV.

Tire failure can be extremely dangerous and can cause extensive damage to your RV. There are no guarantees, but by practicing good tire maintenance and weighing your RV you can feel much safer and secure that the weakest link on your RV will do its job while you're out exploring this wonderful country we live in.

Happy Camping,

Mark J. Polk

Copyright by Mark J. Polk owner of RV Education 101

16 RV Single DVD Titles in our Library

Money Saving DVD Sets Available

Travel Trailer / 5th Wheel Training DVD Sets
Class A Training DVD Sets
Class C Training DVD Sets

14 RV Instant Download E-Book Titles in our Library