Valve Stem Extensions -- Use or Don't Use?

[fagnaml]

This past weekend (10/13/21) while driving home from LSU's win over Florida, my Tire Minder TPMS system went into alarm showing my inside right rear tire pressure was down to 90 psi.   I was in the middle of the 30 mile long Atchafalaya Swamp causeway  and luckily could pull of on an exit to add air to the tire.   I spent an unplanned Sunday evening with my son and his family in Lake Charles as no tire shops were open to provide help (Love's / Speedco said they will not provide tire service to RVs!!).   Monday morning I took the coach to Southern Tire Mart in Sulphur, LA who "diagnosed" the problem as a "cut grommet" on the bottom of the valve stem and they proceeded to change the valve stem.  The repair bill was $40.   Filled the tire to 120# and started the drive to my home in Katy, TX.   Throughout the Sulphur to Katy drive the tire pressure slowly dropped and was down to 100# when I arrived home.

This morning took the coach to Southern Tire Mart in Katy and they found the source of the leak at the bottom of the valve extension the previous owner used.  The rubber gasket at the bottom of the valve extension was "gone" when it was removed from valve stem (I don't know the manufacturer of the old extension).  I purchased a new Milton brand valve extension to attach to the inner wheel valve stem --> Milton 4-1/8in. Truck Valve Extension | Northern Tool   The valve extension is supported by a spring type "stabilizer" --> Wire Valve Stem Extension Stabilizers 4" - Always Shiny Wheels and RV (shinyrv.com)

Without the valve stem extension, for me it is a very painful knuckle scraping, back breaking, contortionist effort to reach the valve stem to check inner tire pressure, add air if needed, attach my Tire Minder TPMS transmitter valve stem cap, etc.  while reaching full arm length through small 3"x4" oval hand-holes in the wheels to reach the inner wheel valve stem.   It's likely the previous owners had similar painful experiences which is why they installed the valve extension.   

Do my fellow forum members use valve stem extensions for your inner wheels of your rear duallies?   If the answer is "no",  how do you reach the inner wheel valve stem to check tire pressure et al without getting bloody knuckles, bruised forearm, sore back, etc.?    If the answer is "yes", what do you do to prevent a leak from the extension?  

Thanks for your thoughts and suggestions!

Edited October 20, 2021 by fagnaml

[jleamont]

Mike, I use sold stainless steel extensions that clear the outer wheel from the inner. Then I have the rubber grommets the press into the wheel hole and hold the stem to keep it stable. I have never had a leak issue. When I pull them off I replace the o-ring inside to make sure it’s a fresh seal.

Edited October 20, 2021 by jleamont

[frank.bergamo]

Mike,

this is what I use,  https://yourtireshopsupply.com/category/796_945/motorhomesbusesclass-alumalum-wheels 
Great product. Hope this helps.

[jleamont]

9 hours ago, frank.bergamo said:

Mike,

this is what I use,  https://yourtireshopsupply.com/category/796_945/motorhomesbusesclass-alumalum-wheels 
Great product. Hope this helps.

Great recommendation! Especially on a vehicle that doesn’t get tire rotations. The rear inner will always be rear inners.

[richard5933]

To me any tire stem extension is adding an additional leak point, as you found out. They are often a weak leak and a cause of problems.

My first approach would be to go to a GOOD tire shop and explore better valve stems for the inner duals. They come in many lengths and. angles, and likely an experienced tire installer can find one which will make it possible to inflate and check pressure without nearly as much knuckle busting.

By having better valve stems installed you could quite likely get the results you need and avoid having to add a leak point.

[hermanmullins]

There are a number of places to get long valve stems for your inside dual tire. They can be positioned where they protrude through one of the holes in your outside wheel. One thing you want to do is get a valve stem stabilizer to help support the long valve stem. To find some goggle "Dually Rubber Valve Stem Stabilizers".

Herman 

[manholt]

Like Joe, never had a problem.

[rayin]

I have flow-through pressure monitors on all tires, the inner duals have a monitor then a valve cap extension on the monitor instead of an ordinary metal valve cap. I've never had a leak from either of those for the past 8 years.

I do carry a 6" extension JIC, but I never leave it installed, it's used, removed and returned to tool box.

Edited October 21, 2021 by rayin

[tireman9]

Valve stem extensions come in two "flavors". One being a longer metal stem the other is some sort of "extender" that screws onto the end of a standard stem.

If you chose the long metal stem route, you probably should have them installed by a tire shop that services Heavy trucks as they have the experience and should know how to install properly. The stem for the inner tire can be straight or almost straight but needs to be long enough to come through the outer wheel "hand hole".  The long stem may look like this one.

 

The outer stem can be a regular brass stem like this one.

 

it will help if you have a "dual foot" inflator tool. Like this.

If you have short metal stems as shown above and a "Dual-Foot" inflation adapter you should be able to get to both the inner and outer short stems.

The above doesn't answer the question for those that use TPMS or want easy access to allow measurement of tire pressure. You can use Hose extenders BUT you REALLY need to pay attention to the following:

1. Be sure to tighten the hose properly. That means no leaks (test with some soapy water) and not over-tighten.  I screw the hose on till the air stops leaking then tighten about 1 additional turn. I then check and confirm no air leak.

2. The outer end needs to be SOLIDLY attached.  I use pop-rivets and the small 'L" bracket that comes with the Wheel Master stainless steel hose kit #8001 or #8005 depending on wheel diameter. Like this. (shown with TPMS sensor)

3. When adding air you should hold the hose so you are not loosening the attachment point.

4. Do Not over-tighten the hose extenders. There are small rubber "O" ring gasket seals that can be torn resulting in a slow leak.

5 As with all rubber parts, I had one of my hose seals fail after 8 years.  The rubber in any seal can eventually fail due to "old-age". This applies to hoses, rubber valve stems and any other rubber part in your car, truck or RV. One advantage of my using a TPMS I was able to see the slow ( 2 - 3 psi per hour) and after a close inspection of the hose extender confirmed the "blowout" of the "O" ring

Edited December 29, 2021 by tireman9