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Old 11-25-2021, 06:05 PM   #41
Tireman9
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Originally Posted by CWtheMan View Post
I'm very surprised that Keystone would use ST235/80R16 LRF ties on a 2020 model trailer; why? because when the RVIA recommended 10% load capacity reserves are applied the tires do not qualify for 7000# vehicle certified GAWRs. Even though the G614 RST has equal maximum load capacity as the ST LRF they are considered plus sized and usually DT will not take it upon themselves to use plus sized tires without some option or approval action by the vehicle manufacturer. Of course, DT is probably not a RVIA member and may have no knowledge of their recommendations (???).

Had I been in your shoes at replacement time I would have questioned Keystone about not meeting the RVIA minimum standard.

On the valve stems: DT was following USTMA recommendations to change valve stems when replacing tires. All valve stems have internal/external sealing gaskets. If DT didn't have them, they could have most likely been found at any large automotive parts store.

https://www.amazon.com/TecUnite-Meta...LCP2J?dchild=1

Doesn't USTMA differentiate between rubber "snap-in" stems and metal bolt in stems? Can you provide a link to the recommendation? I think USTMA is in error or has an oversight if they do not differentiate between metal and rubber stems. The change valves when changing tires is good info for 1999 Rubber stems but not today IMO.
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Old 11-27-2021, 07:23 AM   #42
CWtheMan
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Originally Posted by Tireman9 View Post
Doesn't USTMA differentiate between rubber "snap-in" stems and metal bolt in stems? Can you provide a link to the recommendation? I think USTMA is in error or has an oversight if they do not differentiate between metal and rubber stems. The change valves when changing tires is good info for 1999 Rubber stems but not today IMO.
The USTMA recommends replacing valve stems when replacing tires. They are not going to recommend replacement other than what was provided as OEM. To do so would be stepping on manufacturer's toes not to mention the vehicle manufacturers valve stem responsibilities.

Plus sizing is another matter and would require valve stems suitable for the replacement tires/wheels.

USTMA recommends using the valve stems provided with or recommended for TPMS equipment.
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Old 11-27-2021, 10:01 AM   #43
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The USTMA recommends replacing valve stems when replacing tires. They are not going to recommend replacement other than what was provided as OEM. To do so would be stepping on manufacturer's toes not to mention the vehicle manufacturers valve stem responsibilities.

Plus sizing is another matter and would require valve stems suitable for the replacement tires/wheels.

USTMA recommends using the valve stems provided with or recommended for TPMS equipment.

I know of a couple TPMS vendors that recommend bolt in metal stems. I am also aware that a number of internet retailers are not much more than "order takers" and have no working knowledge of TPMS. I can understand why some do not want to tell the prospective customer that they should replace rubber "snap-in" stems as they are afraid that might kill the sale.


USTMA seems to be more interested in keeping the lawyers away than offering good advice to consumers. I guess my video of a failed "Hi-Pressure" rubber stem is meaningless.
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Old 11-29-2021, 05:09 AM   #44
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I know of a couple TPMS vendors that recommend bolt in metal stems. I am also aware that a number of internet retailers are not much more than "order takers" and have no working knowledge of TPMS. I can understand why some do not want to tell the prospective customer that they should replace rubber "snap-in" stems as they are afraid that might kill the sale.


USTMA seems to be more interested in keeping the lawyers away than offering good advice to consumers. I guess my video of a failed "Hi-Pressure" rubber stem is meaningless.
Hundreds of millions of snap-in valve stems are used worldwide on a large verity of applications. They are inexpensive, reliable and easy to install. And they meet industry requirements.

There are advantages and disadvantages for any application. I always used metal valve stems on the wheels on my 6000# axles. For me the advantage was obvious, itís easier to check and service the tires with mobile compressors. And, like other designs the metal ones fail internally and I replace them whenever I replace a tire.

Let the situation dictate the use of metal valve stems. Youíll be a better friend with Schrader and others.
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Old 11-29-2021, 07:37 AM   #45
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Hundreds of millions of snap-in valve stems are used worldwide on a large verity of applications. They are inexpensive, reliable and easy to install. And they meet industry requirements.

There are advantages and disadvantages for any application. I always used metal valve stems on the wheels on my 6000# axles. For me the advantage was obvious, itís easier to check and service the tires with mobile compressors. And, like other designs the metal ones fail internally and I replace them whenever I replace a tire.

Let the situation dictate the use of metal valve stems. Youíll be a better friend with Schrader and others.

Yes "hundreds of millions of snap-in rubber stems" with few problems but the vast majority did not have a TPMS sensor hanging on the end of the stem. There are a number of variables such as the angle for the stem hole that can affect the level of movement when a TPM sensor is screwed on the end of the stem. There are a number of different stem lengths that will also affect the lever effect and the torque applied to the stem.


Based on my 40 years experience with tire valves and my 18 years experience with TPM systems I recommend that anyone running an external TPM sensor use bolt in metal stems when adding a TPMS to their trailer application. Just switching to the "Hi-Pressure" Snap-in stems will not eliminate the flexing problem.


Sometimes strict adherence to some 50 year old industry guideline is not always the best practice, especially considering the resistance to change seen from those organizations.


Too often political pressure inhibits changes for the better. Look at how long it took for RVIA to adopt the +10% reserve load capacity over the objection of some RV companies. DOT still has no Reserve Load requirement and still limits the TPMS requirement to vehicles with 10,000 GVWR or less as if a 10,100 GVWR vehicle can not suffer tire failure due to loss of air.


I am also curious with your observation "the metal stems fail internally". I have never seen a metal stem fail if not involved with some external accident. What "internal" part have you had fail? We can't be talking about the valve core as those parts are identical in cheap rubber snap-in stems or Hi-Pressure snap in stems and metal stems used in everything from wheel barrows to HD over the highway trucks. If you can provide data I will gladly change my position.
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