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myredracer's avatar
myredracer
Explorer II
Aug 21, 2014

Correct way to install metal valve stems?

I finally got around to installing a new Hawkshead TPMS a few weeks ago just days before we left for a 17 day 800 mile camping trip. We are using Hawkhead T-valves which allow air to be added without removing the sensors. Our rims are alloy.

I had the valve stems installed by a large well-known nnational tire company. They said they could not install the rubber grommets that came with the valve stems on the outside so they installed them on the inside of the rim. They said they do this sometimes if it won't fit on the outside. I wasn't sure about this so I called the Hawkshead distributor who said they are meant to go on the outside.

Then doing some reading on the internet, it seems like it is better to have the grommets installed on the inside because the internal air pressure forces a seal against the metal rim.

Is there a right and wrong way to install the grommets or does it matter? After 800 miles, the TT tires held the air just fine. Hawkshead said that their T-valve grommets should fit on the outside of most RV rims. Maybe the tire shop didn't take enough time and care to fit them correctly?

Another question is that the inside surface of the rim has a round surface but the valve stems came with a flat washer. Should a convex washer be used? Where would I find them?
  • Harvard wrote:
    Short term, I would bubble test. If they go low in pressure over long term you will know why.


    They dunked them all in a tank at the tire shop and were good. I don't know if they can start to leak over time if not done quite right?
  • j-d wrote:
    Perhaps indirectly related, the custom brass stems for motorhome wheels (the ones form TireMan and Borg, there may be others) install with the nut on the inside. They want Blue Loctite on the nut threads. I don't think it's for sealing, but because once the tire is mounted no way to tighten the nut. Were it to work loose, that is. Can be done when nut is on the outside. My take on the Loctite is that it prevents the nut working loose (as opposed to sealing the threads against an air leak).


    I read about using Loctite on one website (red I assume?). The tire shop simply tightened the 2nd nut with a socket wrench. I would have used a thin spanner to hold the first one from rotating.

    The more I think about all this, I think I will get the tire shop to take one tire off a rim so I can look at it closely myself and decide what to do. They said there'd be no charge anyway. The T-valves are supposed to fit standard 0.625" & 0.453" holes. Maybe the tire shop didn't take the time and care to try and get the grommet in place.
  • I wonder what diameter the valve stems would be for an aluminum wheel rated @ 110 lbs. would be?

    I'm getting ready to change the tires on my new Grand Design over to Bridgestone Duravis R250 ribbed tires. And rubber valve stems often cause problems on RV's--need changed to metal valve stems.

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