TPMS systems: I need education

[HowieE]

I attempted to post a response last night from my I Phone but it was not accepted. Seeing that my experience has come into such question I will take photos of my trailer later today and demonstrate the stem deflection that caused the problem that prompted my original comment.

To continue the discussion on TPMS I will add an additional comment. The units have a limited transmission range. With that in mind I suggest that once installed you uncouple the trailer and drive forward about 10 ft. At point test each sensor on the trailer by unscrewing it till you hear air leak. That should cause it to send a signal forward to the receiver. If you do not get a signal consider buying the remote antenna that the better systems offer to extend he range. My Excursion and 34 ft. trailer required the antenna.

You should also be aware that about 3 years back the Chinese shipped some 6,000,000 rubber stems here that failed to the touch of the air hose. They would brake off at the base with some failing just from the centrifugal forces presented at higher road speeds. Oh yes I did have experience with 2 of these failing on my daughters trailer.

Last nights attempted post.

I removed the 10 sensors on my rig because of marks on my aluminum wheels on my trailer and the steel wheels on my truck. Another member in my unit marked his new aluminum wheels in just 150 miles. He converted to metal stems. I will install metal stems on my next tire purchase.

If you still have the sensors on your trailer try the test I mentioned.

I have no vested interest in my post here other than to aid those that ask a question I have experience with. If there are others that have differing experiences than we may open a discussion.

[dznf0g]

All I know is when I had rubber/metal high pressure stems, I had marks on all four wheels and 3 of the four split right at the sealing surface with the wheel. I have external sensors. Here's what Doran has to say about it:


"Tires and valve stems should be inspected thoroughly prior to installation of the system to
ensure they are in good condition and inflated properly. It is not uncommon to find valve stems
that need replacing when installing the 360RV system. Doran recommends that rubber valve
stems be replaced with metal stems. Some rubber stems have been found to be inferior and
could fail prematurely."


Page 1 here:
http://www.doranmfg.com/PDF/Doran360RVmanual.pdf

[cory_can]

Good input Howie. What TPM system are you referring to? I've seen some pretty chunky/heavy transmitters and with some I would also be worried about the mass bending rubber stems. The point of my post (and likely Ken's) is that there are different systems so a blanket statement of having to use metal stems is not completely accurate.....depends on the particular system.

[dkottum]

We bought a TPMS a few years ago and found it gimmicky and another distraction in the cockpit. So when we put 16" Michelin tires on our Airstream that gave us great reliability I decided not to use a TPMS.

There is a good chance a sudden blowout may cause trailer damage even with a TPMS. I always check the tires at each fuel stop anyway. And we have insurance in the highly unlikely event a Michelin 16" LT might blow out and damage the Airstream.

The upgrade to Sendel 16" wheels and Michelin LT tires cost us $1500 after selling the originals. A new TPMS is around $300, and many need new sensors at about $50 each every few years. I don't think TPMS adds any safety, and little to reliability.

Not a recommendation and I don't care to argue the point, just another way of looking at it.

[ghaynes755]

From the TST website.

Do I need special valve stems?
No, you do not need special valve stems, but you do need commonly available metal valve stems.

The added weight of the sensor on a rubber valve stem could cause problems that will be avoided by using metal valve stems.

Most motorhomes and commercial transport vehicles come equipped with metal valve stems. If you do need metal valve stems, they are not expensive; a recent customer had 6 valve stems replaced on a 30’ gooseneck racing trailer for $36. They are available and can be quickly installed by any tire dealer.

[cory_can]

So, what have we learned? It depends on the system....some are lighter/heavier than others. Read the particular instructions and make a decision.

[HowieE]

The first picture shows the gap between the sensor and the wheel. The second shows the point at which the sensor will contact the wheel. This repeated contact and hammering will crack the clear coat on the wheel and cause that clear coat to start to fail about that point. The third picture is the extended antenna I mentioned that may be necessary with larger rigs.

[Ag&Au]

Originally Posted by HowieE

The first picture shows the gap between the sensor and the wheel. The second shows the point at which the sensor will contact the wheel. This repeated contact and hammering will crack the clear coat on the wheel and cause that clear coat to start to fail about that point. The third picture is the extended antenna I mentioned that may be necessary with larger rigs.

That also shows a sensor at least twice as bulky and heavy looking as Hawkshead or Tireminder.

Obviously there is no one answer for all situations and no blanket statement that can be made that you always or never need metal stems.

THerefor I would recommend doing as I did, and follow the instructions from the TPMS manufacturer.

I would be interested in knowing which brands have the large bulky sensors.

It would also be nice if the term "metal stems" were defined. According to DTC I have metal stems, with rubber coating. What I get from reading Howie's posts is that he says "they are not metal stems unless they are the chrome plated bolt in type".

Ken

[HowieE]

By your description I feel safe in saying you do not have metal stems.
Metal stems are "Bolted" in place against a flat rubber gasket on the wheel face. The following link will illustrate the range of metal stems available.

https://www.google.com/search?q=meta...w=1280&bih=640

Chrome is not the defining feature of a metal stem. But rather the mechanical stability they provides.

I watched the Tire Minder video on their site. While I am not recommending their product the video does mention it does make a good case for the points one should consider when selecting a system.

The OFFICIAL WEBSITE of Minder Research, Inc. - Home of the TireMinder TPMS, TempMinder and NightMinder Systems.

And yes there is a considerable difference in the weight of the sensors in my system, purchased 4 years ago, and the newer systems. Mine weighed .7 oz. as apposed to .3 oz. that is now available