TPMS and Rubber Tire Stems

[jcanavera]

Interesting comments on the TPMS and metal stems. Neither my trailer or tow vehicle have a TPMS system but interestingly enough use the same size tires. In two different years on subsequent trips to the same area, I had a stem crack and fail on my tow vehicle and on the Classic. The tow vehicle tires were Cooper's and the valve that failed on the Classic was a Michelin tire. According to the tire dealers both in Michigan who replaced the valves on each tire, the valves were high pressure rated valves.

I had often heard about using metal valve stems back in the days where max inflation pressures of 65 psi on the trailers, rubber stems were used. When questioning my Airstream dealer about that fact, I was told that the stems on the trailers were heavy duty rated for higher pressure usage. Even my GMC tow vehicle which had inflation rates of 80 psi based on load, rubber stems were used.

I talked to the repair shops in Michigan who replaced the valves and they echoed that HD rubber stems were perfectly adequate. As it ended up the common factor has been that I buy tires from Discount Tire Direct or Tire Rack. The major advantage is that they cost less buying from the Internet and due to taxing laws here in Missouri, neither outlet charges sales tax. Obviously I've saved hundreds of dollars in the cost of tires and sales taxes on all my vehicles over the years. Since neither seller has any physical presence in Missouri, they have working agreements with various local tire dealerships to give me low-cost mounting and balancing services. Works great other than with my Airstream, where no dealership in the metro St. Louis area will mount LT tires on the Airstream. I get around that by pulling the wheels off and bringing them to the dealer to mount.

Bottom line that same dealership installed new valves on the tow vehicle and the Airstream (different years). He was instructed to use high pressure valves and upon failure the repair facilities have verified that the valves which cracked were high pressure. So other than blaming the mounting dealer's choice of their valve stock, is there something about tires running at 80 psi that puts more stress on rubber high pressure valves? I do plan on going with metal stems on the next tire change on both the trailer and the tow vehicle. I know we don't hear a lot from the folks here on the forum generally regarding valve failures, and I assume the factory is still putting rubber valve stems on the trailers with either the Michelin tires or Goodyear Endurance tires.

I also find it interesting that both tires failed in different years in Michigan after traveling I 80 and I 94 east bound east of Chicago. I've hated those two highways for years due the battering we take with bad pavement stretches and that terrible dip in I 94 just east of the Oasis McDonalds and gas stop on I 94. Although the failures came just across the boarder of Indiana and Michigan.

Jack

[gypsydad]

Originally Posted by gypsydad

OK; I understand the comments from earlier posts on the rubber valve stems not holding up to the TPMS screw on monitors vs the steal valve stems. Was wondering why I am not having issues like many have posted. I went to my AS yesterday and looked; mine are rubber on top of steal base. They are very stiff, infact, I can not easily move the screw on monitor caps. I then went to my friends new Winnebago 26' and he has 15" off road tires; he just received his TPMS system and wanted my help to install; his valve stems were rubber, but I could easily push them from side to side; no metal at the base of the rubber. I didn't realize they make 2 types of rubber valve stems?? Could explain why some folks have issues and others (including me) have not?

OK; I have the High-Pressure Valve Stem from Discount tire...these are metal/rubber rated for 65+ PSI for use with trucks/trailers. Thats why they are working with my TPMS without issues. As I mentioned they do not easily bend like the other rubber models designed for -65PSI. As I mention, second set of Endurance with these and the TST with screw cap monitors. No issues...yet!

[jcanavera]

Originally Posted by gypsydad

OK; I have the High-Pressure Valve Stem from Discount tire...these are metal/rubber rated for 65+ PSI for use with trucks/trailers. Thats why they are working with my TPMS without issues. As I mentioned they do not easily bend like the other rubber models designed for -65PSI. As I mention, second set of Endurance with these and the TST with screw cap monitors. No issues...yet!

The Discount Tire store in Holland Michigan replaced the stem on the tow vehicle tire. It was on the Cooper tire that had bought from them via the Internet site. Apparently the store has access to the Internet record side so they knew I was a customer. Wish we had those folks in St. Louis. As it ended up they took the bad tire right away and asked if I could come back the next morning. At that point they put the tire with the new valve stem back on the tow vehicle and moved the spare tire back to its storage location which is under the rear of the van behind the rear axle. When I went in to get the bill, they gave me a receipt for $0. Really nice folks there.

In both cases the valve stems cracked just below the area where the stem comes out of the wheel itself. Thankfully I noticed the latest failure when I stopped at the first rest stop in Michigan. As I was getting back from the restroom I did my usually walk around the trailer and the van checking things and noticed the rear tire looked a little low. I touched the valve stem to check the air pressure with my gauge and heard a hiss. I unhitched the trailer to get to the spare on my van and a truck driver pulled up and asked if he could help. I said sure, since I had never had to change a tire myself on the van in all the years I had owned it. He ended up said let me do this. And he did all they physical end. Once he gets the spare mounted he unrolled an air hose from his truck and made sure the pressure was right. I offered him some cash for the help and he turned it down. Wished me a good vacation and went on his way. He was a prince!

Jack

[OrangeCrush]

After close look and talking to Discount tire, they installed the HP rubber brass on mine. They said they are not aware of problems with this type valve and small TPMS sensors. I have had no sign of stem problems. TST website clearly states metal stems required for pass through sensors. It also states metal or rubber for non-pass through. EezRV basically states the same, metal recommended but HP rubber OK except on flow through. They also mention a goofy looking "rubber valve stem support" which looks like a good way to introduce a problem when there is not one to me. I will stick with fresh rubber brass stem HP valves with non-pass through sensors for now. That said, thank you OP for bringing up this issue so we can all investigate and stay safe.

[RMNummi]

Yep I was referring to the composite metal/rubber stems. Definitely rubber at the base/root with the “trunk” being metal. Apparently the centrifugal force and the “bulk” necessary to accommodate the battery is the culprit. Rubber naturally flexes…again w/o any science on my part, after this all started I recalled being flung around the centrifuge at AOCS in P’cola being tested for ability to handle G’s….Light came on. That little TST monitor and it’s battery (at speed) have got to be adding the same g-force to the stem rubber. Hence the metal composite “stiffener”. Again I plead ignorance. Just a Newtonian apple falling moment. I figured if the bored tire tech had seen “hundreds” of these incidents and the addition of a couple bucks each for composite stems….resolved my angst, well worth it IMO. Sorry for the confusion and the initial simplistic reference to “metal” stems (when I was referring to the available upgraded composite metal/rubber).

[Spaggs]

Originally Posted by SuperTrouper

I dutifully put steel stems on the trailer, forgetting about the TV. Heading toward Idaho Falls at 60MPH a few years ago (heading to Yellowstone) with a 40MPH quartering side wind in front of a closing thunderstorm I lost my RF pressure on the Excursion due to a split rubber stem. TPMS and Quick Lane tire in Idaho Falls saved our butts that day. Steel stems all around ever since. - Brad

The Dill VS-902W also is a good fit for Excursions. Made in USA.

[turk123]

There is an easy way to see if your rubber valves are strong enough. I have the screw on TMPS from truck systems that you have to remove with the special tool to add air.

Look at your rim right next to the sensor. If you have a black dot where the sensor is actually hitting the rim, you have a problem. The centrifugal force will actually bend the valve stem to the point where the sensor itself is hitting the rim. It will leave a telltale black mark on the rim. All four of my rims had this black mark.

My rubber valves were installed by the automotive service I use because they didn't have steel valves that would fit my alloy wheels. One year later I had a flat. Fortunately, it was in storage. The rubber valve had completely failed.

[gypsydad]

Originally Posted by turk123

There is an easy way to see if your rubber valves are strong enough. I have the screw on TMPS from truck systems that you have to remove with the special tool to add air.

Look at your rim right next to the sensor. If you have a black dot where the sensor is actually hitting the rim, you have a problem. The centrifugal force will actually bend the valve stem to the point where the sensor itself is hitting the rim. It will leave a telltale black mark on the rim. All four of my rims had this black mark.

My rubber valves were installed by the automotive service I use because they didn't have steel valves that would fit my alloy wheels. One year later I had a flat. Fortunately, it was in storage. The rubber valve had completely failed.

No black dots on my wheels...Also, I have the TST screw on caps...I used the little "installation tool" that they give you, only one time, and since I just reach around the transmitter cap with my finger tips and I am able to unscrew them with no issues. It is tight when I re install transmitter caps also, without need of that little tool they give you.

[Mikemdd]

Quick question.... Do the OEM Airstream 15" aluminum wheels have a 0.453" valve stem hole diameter or the larger diameter? Thanks!

[OrangeCrush]

No black marks on my rims, but stems are the high pressure rubber with brass stem and only about 2 years old.

[RMNummi]

Yep, little black marks on the two that failed. Other ones had little micro-abrasions. Apparently I dodged a bullet on those two. New 2014 AS owner, five year old tires… recipe for a bad outcome. I wonder how many other new owners of used AS’s are in same boat. As an aside, the tire tech said I still had well over half the “useable tread life” remaining on the old GYE’s prior to me changing them all out for new and installing the composite metal/rubbber stems. I learned a lesson that’s for sure.

[RMNummi]

Update: swapped out 5 14” Sendel S20’s for new Sendel T-03’s… asked for metal stems. No more composite…now have Metal stems with rubber gaskets. Total cost for stem swap 15 bucks.

[PB_NB]

I have this on my list of things to do before the next camping season.

I have the TST units and the documentation does not say that metal stems are needed but if you run the flow through sensors that TST makes, they are heavier and TST says that metal stems are required for those caps.

[steilkurve]

Just made the move. Despite having used my TireMinder sensors on rubber stems successfully on my previous AS, I just had metal stems installed on my new AS. My rubber valves seemed in good shape still but I did notice marks left by the sensors hitting on my RIMs.

Did it at a local tire store (part of a chain) recoed by other RVers. Can't tell you the brand of the valve they put in but it is sturdy. See attached photo. Excuse the dirty wheel. Drove back from the store in bad weather!

[hikingcamera]

Just to be clear, are folks here saying that the non-flow through, "capped" sensors that TST advertises as being designed for and compatible with rubber stems are in reality not?

[OrangeCrush]

Originally Posted by hikingcamera

Just to be clear, are folks here saying that the non-flow through, "capped" sensors that TST advertises as being designed for and compatible with rubber stems are in reality not?

I believe that is correct and my local Discount Tire concurs after fixing my valve stem leak. They were the high pressure metal tube rubber base valve stems and my sensors were the small non flow thru EEZTire sensors. Slow leak started at the valve stem base about 1 year and 10,000 miles after new tire and stem install. Prior to that I had 4 years of no issue with the same sensors on the OEM all metal stems. My local Discount Tire replaced the stems with Dill VS-902W at no charge and decided to stock them for future RV tire installations. I called EEZTire and they said metal stems are not necessary with non flow thru sensors and my problem was probably a defective valve stem. They were clear that the high pressure rubber base metal tube valve stems are still considered "rubber". Clear as mud but those are the facts as I know them and I will only use all metal bolt on stems going forward.

[steilkurve]

Originally Posted by hikingcamera

Just to be clear, are folks here saying that the non-flow through, "capped" sensors that TST advertises as being designed for and compatible with rubber stems are in reality not?

I use the TireMinder cap sensor. While the company says it works on both rubber and metal stems, they recommend metal stems. I believe TST says the same thing.

So, rubber will work but due to the risk of failure over time because the valve flexes more, it will require more frequent inspections and a valve replacement at some point.

[Silvr_Bullet]

Originally Posted by steilkurve

I use the TireMinder cap sensor. While the company says it works on both rubber and metal stems, they recommend metal stems. I believe TST says the same thing.



So, rubber will work but due to the risk of failure over time because the valve flexes more, it will require more frequent inspections and a valve replacement at some point.

That’s correct what the TireMinder Manual reads. Some people are not aware that there are two types of metal stems ( a morphed term ) there are stems that are bolted to the rim and stems that have a metal stem and a rubber bulb that makes the connection to the rim ( not metal ). It’s recommended to use the type with a rubber bulb that attaches with a metal stem to the fill valve. See excerpt from TireMinder. This doesn’t apply to dually setups.

https://support.tireminder.com/hc/en...-Transmitters-

[gypsydad]

I posted this earlier; 5+ years now with my "cap" style TST TPMS with the repeater mounted to the A frame, adjacent to the battery box. I also have used metal/rubber valve stems, with "no" issues.

I found out this year while looking at my friends new Winnebago "rubber" stems when he was installing his "new" TST system, there are "different" rubber/metal styles; his were very plyable...you can easily push the stem's and they bend over...the cap style repeaters like I use, would not work IMHO, due to the flexibility of his type stems.

My stems, are metal coming out with a little rubber below the screw and they have worked for me without issue. They do "not" easily move when I push on them, without a lot of pressure; they are very stiff. This pair of GYE's (second set now with these stems) now have 20K miles with these...Next time I change tires, I may ask for steel, but these have been working fine. YMMV

[hikingcamera]

So it turns out our tires do have metal stems with the rubber connection point. So, given that news, is it safe to get the pass through sensors, or is it still safer to stick with the cap style?