* Tire Codes & Tire Care *
TIRE AGE - Knowing the manufacture date of the tires on your RV is very important. Some manufacturers are beginning to lengthen their tire warranty in terms of years, but any RV tire over 5 years old needs to be closely inspected for "checking," sidewall cracks, or other evidence of aging. Any RV tire over 7 years old likely should be replaced, regardless of how much tread it has left. An old tire can fail from the inside out, and any blowout on an RV can at the very least cause considerable damage to the RV. It may also cause loss of control, a serious accident, or a fire.
The picture above shows the code numbers you need to be aware of on your tire sidewall. This code is required to be on every tire sold in the United States, and will normally be found on only one of the two sidewalls near the edge by the wheel rim. The number will begin with the letters "DOT," and end with a 4-digit code indicating the week and year of manufacture. The example in the picture indicates the tire photographed was manufactured in the third week of 2004. Note that if the tire was manufactured prior to the year 2000, the date code will be only 3 digits. The first two indicate the week, and the third digit is the year. For example, 039 would indicate a manufacture date in the third week of 1999. If your tires have a three digit date code, replace them immediately!!
TIRE CARE - There are a few things you can do with your tires to help them age better, and be safe longer. One is to use them! Tires that are regularly "exercised" keep the oils, etc in the tires moving around, which tends to make the tires last longer. Tires that sit and are not used will rot and crack faster than tires that are regularly used.
When your RV is parked, covering your tires can help to prevent deterioration from UV radiation and Ozone. Anything that keeps direct sunlight off the tires will do the trick, from commercially available covers to a simple piece of plywood. We always cover our tires with parked in an RV park for more than 24 hours, and always when the RV is stored. You also should avoid parking your RV next to an electrical transformer, an electric welder, or large electric motors or generators as these items produce large quantities of ozone, which will speed aging & deterioration of rubber, including tires.
Parking your tires on concrete or asphalt is also bad for them. Concrete suposedly leaches moisture/oils from the tires, and asphalt is made from petroleum products which deteriorate rubber. This is true of your car tires in your garage or driveway, but normally you will be using the car enough to wear the tires out before you need to worry about the effects of parking them on concrete or asphalt. Just about anything will work as a vapor barrier between your tires and the concrete. A thin sheet of plywood, thick plastic bag, plastic sheets, rubber mat, etc. will work. We have used "landing strips" from www.rangerdesign.com, but may figure something else out then the landing strips are no longer usable. We have not been particularly pleased with the durability of the "durable, space age plastic" the landing strips are made of. Since they were a little less than 18 months old, they have become brittle with pieces chipping and breaking off the edges. To the right is a picture of a covered tire parked on a "landing strip" vapor barrier.
Parking your tires in standing water is not good, as the water can seep into the tires and rust the steel belts, causing pre-mature failure. When storing your RV, try to ensure the tires are parked on ground slightly higher than the surrounding area. One way to do that would be to haul in a little dirt to place in the wheel positions, or to use wood or other type of blocks under the tires to ensure the wheel positions are not lower than the surrounding area.
If you use blocks to level your RV, or to elevate your tires when storing the RV, be sure (as mentioned above), that your blocks are wide enough and long enough to support the entire foot print of the tire equally, or both tires equally in the case of dual tire positions. Blocking just half a tire, or just one tire in the case of duals, will case internal damage to the abused tire and which can lead to belt separation and catastrophic tire failure. Below are examples of the wrong way to park your RV tires on blocks.
PROPER TIRE INFLATION - Another critical aspect of tire care is to ensure each tire is properly inflated for the load it is carrying. You tires have a "recommended pressure" stamped on the sidewall, but since that pressure is the maximum rated pressure for a tire carrying its maximum rated load, using that pressure will likely give you over-inflated tires, bad tire wear and poor handling. Your RV probably has a placard somewhere that indicates manufacturer recommended tire pressure. The pressure on that card is likely the recommended pressure for the tires that came on your RV when it is loaded to the GVWR of the vehicle. Since your RV manufacturer has no idea what tires are presently on your RV, or how heavily it is loaded, the recommended pressures on that sticker might be good for your tires, or they might be way off. To ensure your tires are properly inflated, you need to have your RV weighed when it is loaded as you normally travel. At a minimum, you need a separate weight for each axle. It would be even better if you could get the weight of each wheel position ...a "four corner" weight in the case of a motor home. With four-corner weights, you can find out how out of balance you might be loaded and whether or not you need to re-distribute some of your load to avoid having one wheel position being overweight for the tires there. Then you can calculate the total axle weights and check those actual axle weights against the maximum axle weights for your RV to ensure no axle is overloaded, and you can calculate the weight each tire is carrying. Then you can refer to the charts published by your tire manufacturer for the tires you have on your RV to find out what the recommended pressure is for that tire at that load. Tire pressure charts are available from tire dealers, or from the tire mfg's web site. If an axle or one end of an axle is over the axle weight rating, you need to remove cargo, fresh water, passengers, etc until the axle is at or below the weight rating. Once you are sure no axle is loaded over its weight rating, and you have shifted cargo from one cornet to another in order to equalize weight as much as possible from side to side, the correct pressure for all tires on that axle is the recommended pressure for the tire carrying the most weight.
CHECK YOUR TIRES REGULARLY - Assuming you have a handle on how old your tires are, how much weight they are carrying, and what PSI they require, all that remains is to do regular pressure checks to ensure they are always properly inflated when you are traveling! You may have to add 5 psi or so to tires when the weather cools off in the Fall, and/or let out 5 psi or so when hot Summer weather hits. Always check your tire pressures when the tires are "cool," ...basically, before you drive on them. Some RVs come from the factory with wheel setups that make it difficult or impossible to check tire pressures. Whatever it takes, you need to ensure that you can easily check the pressure in all your tires. My motorhome came with metal valve stems, and with long metal stems plus 3 1/4" solid metal extensions that stick through the wheel holes on the outside rear duals. All my valve caps are easy to get to. Metal valve stems are your most stable choice. If you have to use extensions, use metal extensions rather than rubber, and ensure they are stabilized to prevent them from moving from the centrifugal force of the rotating wheel while driving. Even one piece metal valve stems can crack from the centrifugal force. My long metal valve stems plus extensions from the inner dual tires are stabilized by a rubber grommet where they pass through the hole in the outer wheel. The grommet is made by Alcoa specifically to fit Alcoa wheels, but they perfectly fit my Accuride wheels also. (I later got some Accuride inserts and found they are MUCH more difficult to insert into the wheels). Another thing I did to make it very easy to check tire pressures daily when traveling was to replace all my valve caps with "Alligator" caps. Alligator caps are metal, dual-seal caps that allow you to check the pressure and add air if necessary "through the cap." This means I do not have to remove and replace the valve caps to check the tire pressures. The dual seal makes it very unlikely the Alligator cap will leak, and they are designed for use on high pressure truck tires. You should be able to find them at a truck tire service location, normally for about $1.00 each. That is also where I got the Alcoa rubber grommets for my rear wheels, after having a cracked valve stem replaced on an inner dual a month after I bought the motorhome. Since adding the rubber grommets, I have driven over 60,000 miles with no further valve stem problems. With the Alligator caps in place, I can check all tire pressures in just a few minutes. The picture on the right is of a rear wheel with Alligator cap & rubber grommet in place on the long metal valve stem from the inner dual.
TIRE TEMPERATURE RELATED TO PSI - The "correct" pressure from tire manufacturer pressure charts assumes "cold" pressure, meaning in the morning before any driving is done. I always check all tire pressures before driving the motorhome ...either the day before just in case something needs to be repaired, or just before hitting the road. Once you have driven even a few miles, any pressure reading will be skewed by the tires being warmer from driving. So rather than checking pressures at every stop during the day, I check the temperature of each tire with a simple infrared thermometer from Radio Shack. The actual temperature of the tires is not all that important to me. What WOULD BE important is a tire that is significantly hotter than a comparable tire (ie. left front vs right front, left inner dual vs right inner dual, etc). Tires on the sunny side will always be a little warmer than tires on the shady side. Inner duals will normally be a little warmer than outer duals. But any tire that is say 15 degrees or more warmer than its comparable tire would be of concern to me. An under-inflated tire would be significantly hotter than other tires, and would indicate possible failure soon. Under normal driving conditions, particularly on a hot summer day, your tires may be as much as 60 degrees warmer than the ambient temperature!
TIRE PRESSURE MONITORING SYSTEMS - After having some flat tire problems on my toad, with a tire once going completely flat very quickly right after pulling off the highway into an RV park, I decided a tire pressure monitoring system would be a good idea to help me avoid dragging the car while unaware it has a flat tire. I know other RVers who have sustained hundreds of dollars damage and even fire from such occurences. Another danger is damage to fiberglass panels on the motorhome if a tire were to overheat for some reason and blow out. So, in addition to junking the Uniroyals I had on the car in favor of Michelins, I decided we needed a TPMS system to monitor a total of 10 tires (6 on the motorhome and 4 on the towed car). There are several manufacturers who make add-on TPMS systems suitable for RV use. Most use sensors that screw onto the tire valve stem, while others have a sensor attached to the wheel inside the tire. Each also has a monitor inside for the driver to observe. The sensors broadcast periodic RF signals to the monitor about the tire pressure, slow or rapid air leak, and on some models the air temperature inside the tire.
OUR TST TPMS EXPERIENCE - In 2009, we bought the TST TPMS from Truck Systems Technologies. It included a small LCD monitor, and 10 valve stem sensors that track PSI and temperature. TST sensors install with a small wrench to deter theft, and weigh 58g each. They measure both tire air PSI and temperature. In order to ensure the inner dual wheel long valve stems w/extensions would not be flexed due to centrifugal pressure while driving, I altered the rubber grommet stabilizers as you see here to accommodate the size of the sensors. After the first trip with the TST system in place, I had to also buy the optional signal booster as the monitor was dropping signals from the car while it was being towed behind the motor home. After running the TST TPMS system for 8 months and apx 6,000 miles, we returned it for full refund. According to TST, they have about a 1% return rate. The TST people were great to work with for customer service, but after 8 months we had replaced 8 sensors under warranty and had 3 more that were giving false readings. In addition, we had experienced 2 flat tires on the Honda due to leaking sensors. Each time, the tire went flat while the car was parked, apparently after a sensor worked loose while the car was being towed or driven. At that point, we did not trust the system and I was afraid to let my wife drive the car without me ...we're looking for more peace of mind while RVing ...not something else to worry about!! We went back to the original setup with the Alligator caps pictured above, coupled with manual pressure checks with a good gauge and temp checks with the infrared thermometer during stops while underway. After extensive searching online, since I cut the centers out of the original stabilizers to accommodate the TST sensors, we also bought new valve stem stabilizers from www.realwheels.com, this time made by Accuride. As noted above, the Accuride stabilizers are WAY more difficult to insert into the wheel holes.
OUR TIRE_TRAKER TPMS EXPERIENCE - In Fall 2010, we bought a TireTraker TPMS after examining it at a SMART National Muster and doing subsequent research on the system. The TireTraker (also sold under the Hawkshead brand) is similar to TST in terms of tracking tire PSI and air temperature. The TireTraker monitor pictured here is small pocket-sized and is very easy to move from motorhome to car depending on which we are driving at the time. A bracket is provide to hold the monitor if desired, and the excellent suction cup base will securely grip glass of a smooth dash surface, or can be attached with provided velcro tabs. Note the display is showing 95 degrees on the right front tire of the toad. The sensors are much smaller and lighter than the TST sensors, at 9g each compared to 23g (.3 oz compared to .85 oz). One big advantage is that these sensors have replaceable batteries, using a common CR-1632 watch battery. On systems without replaceable batteries, sensors have to be returned to the company for either battery replacement, or total replacement, at apx $20-$50 each when the batteries die (every 5 yr or so??).
The picture on the left is of the Tire Traker sensor on a motor home rear outer dual, and on the right on an inner dual. The TireTraker sensors come with optional lock rings, each to be secured on the valve stem on the inner side of the sensor with three very tiny set screws tightened by a provided very small allen wrench, AFTER the sensor is screwed on. The lock rings would be quite difficult to put on at best (and impossible on some wheel positions), and we don't feel the need for them at this point, so we have not used them. After some experimenting with the rear inner duals with the modified stabilizers pictured above, I got some 4" solid metal extensions to replace the original 3", and new stabilizers. The picture here on the right is what they look like now ...perfect length of the extension makes them easy to remove/replace, and the stabilizer holds them in place. Although we have Accuride aluminum wheels, I found that the Accuride stabilizers did not work well as they are much harder to get in place and the thin inner rubber is distorted by the extension. So I got a new set of the Alcoa stabilizers you see in the pitures. They are much easier to work with, and are not distorted by the sidward pressure of the extension if it does not perfectly hit the center of the wheel hole.
We have had the TireTracker system in operaton for a over two years and and several thousand miles. The system has performed very well. We do have a few "false alarms" after stopping for fuel, but I had read of that possibility. It seems as tires cool quickly in some circumstances that can trip the "leaking" alarm. But when the monitor indicates the pressure is not dropping, it is pretty obvious there is no problem. ...and we have had no loose or leaking sensors! The only irritant is when using the monitor in the toad when the motorhome is parked somewhere, we will get an "alarm" when the monitor looses signals form the motorhome tires which are several miles away. To get around that irritant when we were parked for an extended periond while visiting kids/g-kids, we totally removed the motorhome sensors. That was simple to do, and re-installing the 6 motorhome sensors was quite easy. All in all, the TireTracker system is working great for us.
PRETTY TIRES & TIRE TREATMENTS - One other thing to be aware of ... all those tire treatments that leave your tires looking all wet and shiny are "must-have" for show car owners, but most of those products are bad for your tires! Most such products are petroleum based, and while they are making the tires look pretty they are also pulling moisture out of the rubber and causing premature aging. If you check with your tire manufacturer, you will likely find that they recommend cleaning your tires with mild soap and water only, and then rinsing thoroughly to ensure the soap is removed. If you insist on using something on your tires to "make them look pretty," make sure you something that contains no petroleum products. One such product, which does provide some protection from UV deterioration, is 303 Protectorant.
TIRE CARE WRAP-UP - So,
- Know the date of manufacture on your RV tires,
- protect your tires from deterioration from UV rays and Ozone,
- use a vapor barrier under your tires when parked on concrete,
- if you use blocks under your tires for leveling, use large enough blocks, and use the blocks properly,
- keep your tires inflated to the correct pressure for the weight they are carrying, and monitor your tire pressures and condition frequently,
- do not use any petroleum based "tire treatment" that in reality damages your tires,
AND, be sure to use your tires often enough to keep them "exercised" ...that's what you got the RV for anyway, right? ...so USE it and ENJOY it!
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