Tire Valve Stem Deterioration

I checked my TM tires and three of the five (dual axles) were low/about 20psi. All five valve stems were cracking and/or splitting where the stem comes out of the wheel. Two tires lost air when I wiggled the valve stem prior to checking the tire pressure. They were also cracking around the base of the stems; they would not hold air.

Good thing I checked several days prior to taking off, rather than the customary night before, as it took me a good part of a day to remove the tires, take them to an auto shop (two trips) have the stems replaced, then reinstall the tires.

I was told the original stems were "low quality", and most probably from offshore manufacturers. Such stems are made of inferior materials that don't stand up well over time to the sun, ozone, heat and cold temperatures. I learned that there is a huge difference in the long-term reliability of these cheaper no name valve stems.

When replacing valve stems ask if they meet the SAE 1205-1206 standards. Off shore products usually are no-name products. Stems meeting USA standards always have their manufacturer's logo or country of origin on the bottom of the stem (which cannot be seen when a stem is installed). When having stems replaced ask to see them before installed. If no logo or other identifying marks are on them, be very suspicious. Reputable manufacturers' valve stems are QS9000 or ISO9000 certified, which means they meet stringent quality control standards, procedures and recordkeeping.

So, words to the wise--often check your tire pressure as well as the condition of the valve stems. If the stems show signs of deterioration, cracking being hard or brittle, and the like, have the valves replaced. Taking tires off a TM is no fun, but it is down right dangerous if it has to be done on the road.

Did a quick check under the "Search" option, and found that five of us TrailManor Owner's Forum members with a 2004 TM have experienced multiple tire failures due to tire valve stem deterioration.

If you have a 2004 TM be especially vigilant in examining your tire valve stems.

I don't own a 2004 TM, but your advise on being vigilant should apply no matter what year you have. I make a vigilant check of both the tires and the stems before I make each trip... and make sure you have 50 lbs in those tires... You can never be too safe when it comes to towing...

Well stated, "You can never be too safe when it comes to towing..." Thanks. I would add to your post, though, the following:

Not all TM tires should have air pressure kept at 50 lbs. The TrailManor Owner's Manual states, "....Air pressure should be kept at 50 p.s.i. for 14" tires and at 65 p.s.i. for 15" tires...." The manual goes on to provide very basic information on tire care, including the proper torque specifications (90 to 95 foot pounds)--which I wish I had remembered when putting on my four tires. Had to go back and loosen the lug nuts and retighten them to specifications. This aging brain of mine sometimes misses a thing or two. I'm going to have to start re-reading my TM Owner's Manual at the start of each travel season.

In my original post I didn't mention that the auto shop young man that replaced my valve stems did so with "high pressure" stems (the tube around the valve core is metal). He said that he preferred these on trucks and trailers, although my particular application may not really need them.

Has anyone ever had high pressure (metal) valve stems installed? When are these really indicated and when are they just a matter of preference?

[Joe]

I think he did you a favor. The last time I bought a trailer tire I asked for a metal stem and thats what they put in. I wasn't aware of any pressure ratings. As a result of your posting, I did a search for 'high pressure valve stems' and got a lot of hits. Here are a couple : http://www.tirereview.com/?type=art&id=1851&, http://dillaircontrols.com/.
I think we should all be aware of the matter. My TM has 15 inch tires and calls for 65psi.

The metal stems will solve a problem that occurs if you purchase certain in-TV tire pressure monitors. Rocky Mountain Ray reported that at least some monitors include a sensor that mounts to the valve stem. This extra weight causes the stem to flex under centrifugal force that comes from increasing tire speed. The flexing could certainly be expected to induce wear and possibly failure of the stems. If you're thinking of ordering this type monitor, as we are, metal stems seem like a great idea. Thanks, Ray, for passing this on.

(I'm not sure exactly where his discussion resides. Try a search under Tires, Tires, Tires.)

[rickst29]

slightly OT: Dixilou and Joe, our TM manual is wrong about tire pressure. (Maybe they didn't want to go into a full page of details about tire loading, so they just tossed out the biggest number the tire can handle.)

First, if you want to drive FAST on freeways/Interstates, Goodyear now approves running the Marathons at up to 10 PSI *above* the marked sidewall pressure. Read:
http://www.goodyear.com/rv/pdf/marat...nfo_032806.pdf

But, perhaps even more important, Goodyear recommends that you tune your tire pressure downwards when the tires are NOT fully loaded. Full document here:
http://www.goodyear.com/rv/pdf/rv_inflation.pdf

Following is copy/paste from an earlier Thread here:
http://www.trailmanorowners.com/foru...ead.php?t=3357
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Here are the recommendations for the Marathon ST225/75R15, the tire I'm talking about:

max load <> recommended
per tire: <> cold PSI:

1060 lbs <> 15 PSI
1260 lbs <> 20 PSI
1430 lbs <> 25 PSI
1600 lbs <> 30 PSI
1760 lbs <> 35 PSI
1880 lbs <> 40 PSI
2020 lbs <> 45 PSI
2150 lbs <> 50 PSI (max load and PSI for class 'C' load rated)
2270 lbs <> 55 PSI
2380 lbs <> 60 PSI
2540 lbs <> 65 PSI (max load and PSI for class 'D' load rated)

Now... let's think about a 3023 (the most extreme example, because it has the biggest payload). Dry weight is only 2915 lbs, and TM indicates a load capacity of 1928 lbs. Under maximum load, the axle is at about 4770 lbs (with 13% of the payload moved forwards onto the tongue, but 4% of that pushed back to the TM axle by a WDH). That's less than 2400 lbs per tire, even when the TM is loaded to the absolute max.

Unloaded (less loaded to begin with, or coming back home, water tank empty, gray and black water dumped, etc.) you're probably around 3600-3800 lbs on the axle (remember, TM doesn't count options such as AC in dry weight, that's still there). Maybe 1900 lbs per tire, maybe even less. For CORRECT tire performance (the right amount of "give" is needed to make the contact patch large enough) Goodyear recommends only 40 PSI. Run it at 65 lbs, and your trailer is getting shaken to death on the rock-hard tires, and your "contact patch" with the roadway is way too small.

I don't run MY tires all the way down at 40 PSI, even though Goodyear says that I should. But 65 is way to much for a road surface which has typical bumps, it's definitely WRONG to run that way except on the very smoothest of roads.
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BTW, my own 15" Marathons and "bigger" axle are supporting a nonstandard 2619: I have even MORE load capacity than the standard 3023 (if I center it), and even LESS weight when empty-- on the same axle, wheels, and tires. Except when adding 10 PSI to cruise FAST on freeways, 65 PSI would be completely nuts for me. I'm usually running 45-55 PSI, depending on the load and road conditions, and even this is 5-10 PSI more than Goodyear recommends for operating at normal speeds on "normal" roads.

are there LT tires for a 3124KB ????
family is very concered about marathon blowouts!!!!!
thanks bill s

[kempert]

Light truck tires are not for use on trailers. They are made under specifications for different purposes. I suggest you read more on this discussion thread ("Tires, tires, tires") and check out some of the links.

BTW - It appears that GY marathons are just as good, if not better, than the other brands of tires. Many people take tires for granted and do not properly take care of them.