TPMS on rubber or metal valve stems?

dsttexas · 07-21-2019, 04:58 PM

I bought a set of 4 TireMinder Smart tire pressure monitors and before I mount them I'm curious if other owners have installed them on standard rubber valve stems without issues or needed metal ones. I also believe rubber stems are only rated up to 60lbs psi but I've been running 80 for 4 years without problems. The rims should be good up to 100 I believe. I need 80 for my tires.

Each valve unit only weighs 0.5oz including battery so doubt any issue with centrifugal force causing problems. I looked into steel valve stems but local tire dealer can't find any outer mount ones that fit the hole in my rims because rim hole is somewhat buried within shoulders and can't get tool around it. So far I have found one set of Inner Mount solid brass valve stems that only come in 0.453" stem hole size and not the larger 0.625". I'm not sure what my rims have for hole size yet.

TireMinder Owners manual only states possible issues with rubber valves if using valve extenders and suggests steel ones in that case.

Canonman · 07-21-2019, 05:09 PM

I had metal valve stems installed when I upgraded the Cougar to Carlisle LR-E tires and installed our TPMS. As for psi rating for rubber valve stems the LR-E tires on the Ram are rubber and have 40k miles al at 80 psi. New tires for the Ram planned soon and these will have metal valve stems. I did have a valve stem break on our Chrysler and do not want to deal with that while traveling with the RV.

LHaven · 07-21-2019, 05:10 PM

I ran my Smart caps twice cross-country (AZ/FL RT). Last year on my old rig, which had three rubber valves and one metal (no idea why). This year on my new Cougar, all rubber valves. I had no stem-related issues (just a cracked plastic cap from overtightening that let rain in and ruined one unit).

On the Cougar, I see that the wheel design actually cradles the rubber stem out to where the metal starts, so that makes me feel even better.

**sourdough** · 07-21-2019, 05:20 PM

I believe rubber valve stems can go to about 100psi if I recall depending on hole size and construction of the stem.

That said, virtually everyone will recommend a metal stem. I am in the minority I know but I have rubber stems. When I had the new tires installed at the RV dealership the SM advised me that steel stems on the aluminum wheels to just carry the TPMS heads caused them more trouble than rubber and recommended against it. I went with that. The tires are now 3 years old and the TPMS has been on them all the way (I run 80 psi). I have had no issues whatsoever and I do keep a close eye on them. I had read of issues of the TPMS transmitter damaging the wheel because the rubber stem let the head "flop" around. I have had none of that. I do have a little black mark on one wheel behind the transmitter from "something" but I know not what.
I also have pretty short stems. If they were long stems I suspect they would move a lot more.

I will replace the tires one of these days but I'm loving the Carlisles I put on there so may wait another year or so. At that time I will probably go with the steel stems because the rubber under the little transmitter may cause problems the older they get. JMO

Hblick48 · 07-21-2019, 06:46 PM

I installed TPMS onto rubber valve stems. About 1,000 miles into the 9,000 trip, I noticed circular black marks on all 4 rims. Exactly the pattern from valve stem bending enough for TPMS touch rim due to centrifugal force of spinning wheel. Pulled the TPMS and replaced with standard caps until I was able to install steel valve stems.

Strongly suggest steel valve stems, guaranteed that rubber stems will eventually fail with TPMS attached.

Murdock · 07-21-2019, 07:04 PM

I have been told by multiple tire dealers that rubber stems are not rated for load range E tires, running at 80 psi. They are the experts, I go with what they say.

**sourdough** · 07-21-2019, 07:11 PM

Quote:

Originally Posted by Murdock

I have been told by multiple tire dealers that rubber stems are not rated for load range E tires, running at 80 psi. They are the experts, I go with what they say.

I have been told differently multiple times and in fact LRE tires commonly come with rubber stems. Go with your "experts" but....(note the chart for tubeless high pressure tires about 1/2 way down) -

https://www.tirerack.com/tires/tiret...jsp?techid=208

mwemaxxowner · 07-22-2019, 02:54 AM

I hate to be that guy, but we've had several super duties go deep into the 3 and 400,000s between myself and my dad with only rubber valve stems on E rated tires for the entire duration of our personal ownership of them. I know the fella who still drives my old SD, and it still has rubber valve stems. I'm not sure I'd trust an "expert" who says you can only run all metal valve stems with 80psi.

FlyingAroundRV · 07-22-2019, 03:06 AM

Like the OP, our rims can't accomodate metal valve stems. We did 11,000 miles last year with pass thru sensors on rubber stems and no problems at all. Our tires are rated for 65PSI, so I can't comment about the pressure limits.
This year, I had new GY Endurance tires fitted and asked for metal stems. The tire shop couldn't fit them because of the rim design. So we're on rubber stems again this year and so far have done 1400 miles.

Ken / Claudia · 07-22-2019, 09:59 AM

CW posted information with photos several years ago on valve stems and each styles psi limit. I believe it showed the rubber with brass shaft inside of it was made for 80psi. There are some rated much lower. I found out the tire shop put rubber rated at 65 psi in my 80 psi tires. During 100 plus degree temps and travel with a loaded truck I blew 2 tires from the rubber stems splitting and flying out of the wheel. Remember those style rubber are held in place by a rubber ring inside the wheel. I then got steel/chrome stems on last f350 and this TT. They are held in place with steel and a nut inside the wheel. On the current f350, it has factory TPMS on the stem. It is rubber and brass unknown how it is attached inside the wheel. I suspect it is screwed together, but that is just a guess on my part.

CWtheMan · 07-22-2019, 12:51 PM

The U.S. Tire Manufacturing Association (USTMA) recommends metal valve stems and caps with rubber seals for all RV applications.

When purchasing aftermarket TPMS equipment, does the equipment manuals address valve stems?

**sourdough** · 07-22-2019, 01:58 PM

Quote:

Originally Posted by CWtheMan

The U.S. Tire Manufacturing Association (USTMA) recommends metal valve stems and caps with rubber seals for all RV applications.

When purchasing aftermarket TPMS equipment, does the equipment manuals address valve stems?

Here is what CW is referring to (thanks). Page 41 starts for RVs and the portion CW mentions is on page 43 in the section "Valves".

https://www.ustires.org/sites/defaul...TruckTires.pdf

I'm wondering why this isn't included in RVIA rules? As a previous post said, I've seen LOTS of trailer tires without metal valve stems and they are coming off the line every day. I'm also wondering what USTMA considers "high pressure" and at what level they think this recommendation should kick in. I certainly understand the thought with tires running 100+ psi but to just stipulate "rv's" is extremely vague and probably misleading IMO.

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