TPMS on Brass or Aluminum Stems

[partsrod]

I am looking to buy a TPMS for my motorhome and in looking on the 'net one of the brands said it will only work on brass or aluminum stems. Is this true on all brands or is it just something to do with the temp sensor part only? I cant see that it would affect the pressure. Thanks for your expertise.

[JOHNDONNA]

Aluminum valve stems and brass TPMS Senders don't play well together. Many cars with factory TPMS valve stems from about 2007 are aluminum. Dissimilar metals cause corrosion issues if left in contact with each other for extended periods of time. In my case I had to replace the TPMS valves on my car (toad) and the Pressure Pro senders because I left them on my car too long.

It's best to remove the brass senders from your toad when not needed, or make sure that your toad valve stems and TPMS senders for the RV are compatible.

John

[kaypsmith]

If dissimilar metals is the only problem, wonder if Noalox would be helpful.

Kay

[kaypsmith]

Did a little further research, and here is an interesting article. http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=152 Tireman probably can add some good comments to this.

Kay

[tireman9]

The use of the "silver" valve cores is a MUST if you have aluminum stems as seen on a lot of OE TPM sensors and a few aftermarket ones. I have seen corrosion when brass cores were used in aluminum stems.

RE TPM sensors on brass or aluminum stems. I have heard that some TPM systems offer different material in their sensors but i have not investigated this by trying to contact numerous sensor companies. I think most are probably brass threads in the sensors.

I am using a set of internal sensors from Hella. These are actually passenger sensors and have a 75 psi max. They are aluminum. I have had no problems with the brass external sensors I use, but I give the stems a shot of WD-40 each season and have never driven in snow or salt so I am keeping the potential for corrosion between the sensor and stem to a minimum.

I am also extending the battery life by removing the batteries from the sensors when no travel is expected for 3 months or more so with relatively frequent sensor removal and fresh lubrication I have seen no signs of corrosion.

If you have brass stems and brass sensor you should have no problems with metal compatibility.

I expect to have to remove the Hella sensors when their batteries die in a year or so. At that time I will be installing bolt in chrome or nickle plated brass stems.

Hope this helps.

[desertdeals69]

On Tire Minder if you have aluminum stems you have to use transmitters with aluminum threads.

[tireman9]

A dab of Neverseize will also slow corrosion of Aluminum when in contact with Brass.

You can also get "dielectric grease" at most autoparts stores. This is the stuff used in light bulb fittings to prevent the corrosion of the brass bulb base with the steel socket. Good stuff to use in any electrical connection in RVs as I have seen few water tight connectors used in the RV industry as is used in most electrical connections in vehicles from "Detroit". It would probably be good to have in tool box to help with exposed ground connections too.

[Tandava]

The pressure monitors on rubber stems weigh enough to throw the tire out balance to the point where it can't be balanced because they "sling" around and vary greatly with speed. Metal stems avoids the problem.

[tireman9]

The pressure monitors on rubber stems weigh enough to throw the tire out balance to the point where it can't be balanced because they "sling" around and vary greatly with speed. Metal stems avoids the problem.

You are correct.

I think it is possible the original information may have been misinterpreted. To my knowledge most "Metal" valve stems are made of Brass. Some are plain Brass color and others are Chrome or Nickel plated.

Most bolt-in TPM sensors are Aluminum and as posted above a small dab of never-seize or Di-electric grease is needed to lessen the chance of corrosion. Since you will probably be needing to add air every month or so you can keep an eye out for corrosion.

I have been running external sensors, with Brass threads on Aluminum TPM stems (yea I run two TPM systems as part of a long term test). I do remove the external sensors when no camping is scheduled for a few weeks and I make sure the threads are lubed when I re-apply the sensors. You don't need a lot just enough to coat the threads.

I would recommend against using anything like RTV or Silicone as you don't need a pressure seal and a small piece of cured Silicone could get in the valve core and cause a slow leak.