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Thanks for the information and sorry to open an old thread, but I think this is still relevant. I finally pulled the trigger and swapped out the Continentals (terrible in the winter) for Toyo M655’s. I also went up in size from 225 to 245 to get the extra 1000# weight rating. Of course, there were unintended consequences. I run Centramatics and TST TPMS (cap style). With the old tires, I could just get my hand between the tires to remove the TPMS cap. Then my Milton 553 would work fine to check/adjust tire pressure. Now I can’t get my hand in there and it is a little cumbersome to have to remove the outer wheels just to check the inner tire pressure. So, I’m (along with everyone else) looking for a solution.
My first thought was using a 23mm wobbly socket that will fit over the TPMS firmly enough to take it off. Not a great solution and it is difficult to line up the threads when putting it back on.
So, now I’m looking at extensions for the inner wheels. The Air Flexx looks good and I think it should handle the TPMS cap ok. A reviewer on Amazon had that set up and no complaints. However, am I not defeating the safety factor of a non-pressurized extension by using the TPMS cap? I guess if completely severed, the pressure would hold. Also, several have reported trouble getting air chucks to work with the Air Flexx.
The other option I thought about was a rigid extension, but I’m not sure the angle of the OEM valve stem (metal) and wheel hole line up (or not lining up) would permit this. Rigid Extensions on NAPA
I'd agree you're mostly defeating the point by using TPMS valve caps. Can you not have TPMS valves installed?
I'm more concerned about defeating the point of the unpressurized extension. Ford does not install TPMS on F-450's with 19.5" wheels. Might be possible, but that's another rabbit hole to go down.
I'm more concerned about defeating the point of the unpressurized extension. Ford does not install TPMS on F-450's with 19.5" wheels. Might be possible, but that's another rabbit hole to go down.
Yes that's what I mean, depending on TPMS valve caps requiring pressurizing the extension is defeating the point.
Ford installs TPMS on 22" passenger wheels though so it's not like the 19.5"s are too big or TPMS causes too much imbalance at that radius or something. I've got $20 that says these commercial wheels and tires Ford receives as mounted sets and because they're commercial coming from a commercial source there's no TPMS and it's not worth the money for Ford to rip them apart install them and reassemble. I very seriously doubt there's a technical limitation.
Yes that's what I mean, depending on TPMS valve caps requiring pressurizing the extension is defeating the point.
Ford installs TPMS on 22" passenger wheels though so it's not like the 19.5"s are too big or TPMS causes too much imbalance at that radius or something. I've got $20 that says these commercial wheels and tires Ford receives as mounted sets and because they're commercial coming from a commercial source there's no TPMS and it's not worth the money for Ford to rip them apart install them and reassemble. I very seriously doubt there's a technical limitation.
Yes that's what I mean, depending on TPMS valve caps requiring pressurizing the extension is defeating the point.
Ford installs TPMS on 22" passenger wheels though so it's not like the 19.5"s are too big or TPMS causes too much imbalance at that radius or something. I've got $20 that says these commercial wheels and tires Ford receives as mounted sets and because they're commercial coming from a commercial source there's no TPMS and it's not worth the money for Ford to rip them apart install them and reassemble. I very seriously doubt there's a technical limitation.
Commercial tires are too thick for most internal valve stem TPMS like the ones on the F350 DRW. I have 16-ply J-rated Continental trailer tires and I cannot get a good enough signal with internal TPMS. I can run valve cap TPMS no problem though.
Commercial tires are too thick for most internal valve stem TPMS like the ones on the F350 DRW. I have 16-ply J-rated Continental trailer tires and I cannot get a good enough signal with internal TPMS. I can run valve cap TPMS no problem though.
Sounds reasonable. The tire shop's machine could not mount them; they used bars. This is not one of those national chain shops; these guys service all kinds of big trucks and buses. The manager told me that big truck tires were much easier to mount than 19.5's.
Commercial tires are too thick for most internal valve stem TPMS like the ones on the F350 DRW. I have 16-ply J-rated Continental trailer tires and I cannot get a good enough signal with internal TPMS. I can run valve cap TPMS no problem though.
Interesting. I would not have thought the tire could attenuate the signal that much, today I learned!
I found a set of good ones, from Germany. Unique, ultra lightweight materials. Non pressurized. Quite stiff, for less susceptibility to centrifugal whipping. Yet flexible enough to resolve any angular difference between the projection angle of the factory valve stem on the inside dual rim, and the inner axial perimeter of the hand hole opening on the outside dually rim. In fact, the modulus of elasticity of the unique material can tolerate severe manual bending, but left alone, the material is stiff enough (and light enough, reducing the influence of its own mass) to be used without any stabilizer brackets or wires.
I want to thank you for your post, well written insight, solid images snd the time you took on what may seem like a small subject but critical when you have to actually add air!!!
I was able to locate everything I needed for my dually and sourced everything from Amazon and have in house in two days.
I ended up removing the extender and it is indeed a 7.5" Air-Flexx extension. I tried the inflate through cap on my pickup and it works just fine. However, I don't see how the Air-Flexx extension can even work correctly. When I shake the extension, I can feel the innards sliding from end to end, all as one piece. Think of it like I had a closed cigar tube with a metal bar in the closed tube and it would slide from end to end when shaken. The 'innards' of the extension have right around 5/8" of travel, which seems too much. I'll attach two photos which illustrate my point. When I use a paper clip to push the valve side all the way in, the cable supposed to push the Schrader valve at the other end just barely is long enough to extend maybe 1/32" past the end of the extension. At this point, the paper clip on the other end is about 5/8" into the extension. It appears that screwing the extension onto the wheel valve stem does not push the 'innards' far enough back up the pipe, so to speak, to let the air gauge touch it. The Schrader valve on the end looks like it's still recessed a good 1/4" from the tip. There's no way the gauge or air chuck can reach the Shcrader valve to push it in. To me this appears to be faulty construction. I should be able to simply screw this extension onto a tire valve and then use an air gauge right as it sits, with or without a flow through valve at the end. I would leave the wheel as is now but cannot get an air chuck on the inner rim. The wheel simulator holes appear to cut off about 1" of travel vs the regular wheel and make it just impossible to get the air chuck on straight. sigh...
I finally today got around to installing mine. Indeed out of the box they would not work because the internal wire was not quite long enough. However another way of looking at it is that the base that screws on to the valve stem is too long for the factory valve stem. They are indeed very deep. If you look at TAC2022's first photo which is of the base, you can see that there is a small circle imprinted on the side. I trimmed the base down such that the bottom was just kissing the edge of the circle, so between 2-3mm. With this trimmed off the base would still snug up firmly to the valve stem but it also took up all the necessary slack so they work when putting on the air chuck. I also use fill-through valve caps and it all works with those as well. Importantly trimming these does not take away any thread engagement at all. The interior of the base has something like 8mm of bore before the thread starts.
I don't think there's anything wrong with the product per-se, I think it's the design of the solid bolt-in valve stems that Ford installs which are a little bit shorter than typical and have a hard shoulder that these will bottom out on first before actually threading as far as they're designed to. With a longer valve stem that these can thread all the way down on I expect they would work fine OOTB.
I finally today got around to installing mine. Indeed out of the box they would not work because the internal wire was not quite long enough. However another way of looking at it is that the base that screws on to the valve stem is too long for the factory valve stem. They are indeed very deep. If you look at TAC2022's first photo which is of the base, you can see that there is a small circle imprinted on the side. I trimmed the base down such that the bottom was just kissing the edge of the circle, so between 2-3mm. With this trimmed off the base would still snug up firmly to the valve stem but it also took up all the necessary slack so they work when putting on the air chuck. I also use fill-through valve caps and it all works with those as well. Importantly trimming these does not take away any thread engagement at all. The interior of the base has something like 8mm of bore before the thread starts.
I don't think there's anything wrong with the product per-se, I think it's the design of the solid bolt-in valve stems that Ford installs which are a little bit shorter than typical and have a hard shoulder that these will bottom out on first before actually threading as far as they're designed to. With a longer valve stem that these can thread all the way down on I expect they would work fine OOTB.
Are you guys ( @TAC2022@seijirou ) first removing the OEM brass inflate through valve caps before attempting to thread on the Air Flexx extensions?
The inflate through valve caps have threaded ends that make them appear as if the end of an uncovered valve stem, but they are actually double sealing valve stem caps that are inflate through, and the threads on the end are so that remote inflators have something to grip onto.
They are also the same color and material (brass) as the valve stem itself, which also makes them appear as if they are the original stem. But they are actually removeable without disturbing the stem, and would have to be removed in order to access the valve core, should that ever become necessary.
Because these metal inflate through valve caps have a knurled body that the fingers grip when screwing them on and off, and because the inside diameter of this knurled body exceeds the outside diameter of the threads of the actual valve stem upon which it is threaded on as a valve cap... then by definition, the outside diameter of the valve cap may be larger than the inside diameter of the Air Flexx extension orifice, which is designed to thread over a valve stem, not a valve cap.
Some industry trade names / part numbers for all metal double sealing inflate through valve caps are:
- "V2B"
- "DS1"
A search for either of the two part numbers immediately above will show photos of what I am talking about.
Ford issues these as standard equipment on F-450 tire valve stems.
If the Air Flex is being screwed over these double sealing caps, the body of the Air-Flexx may encounter the body of the V2B before the Bowden cable in the Air-Flexx is able to engage the transfer mechanism within the double sealing valve cap (which in turn, engages the valve core stem).
Simply removing the double sealing valve cap from the valve stem will likely enable the Air-Flexx extension to work without any cutting or modification.
I was able to screw my set of Air-Flexx extensions directly on to the short metal valve stems that are the same trade number as what Ford currently installs on new F-450 / 550 trucks with 19.5" wheels.
As you can see in my photo below, I re-utilized the V2B double sealing inflate through valve cap on the outboard end of the Air-Flexx.
Good question. I use the "DS1" valve caps so I can for sure confirm I am not installing the Air Flexx onto the inflate through caps, they're directly on the valve stem.
The valve stems themselves aren't very tall though, and the Air Flexx was bottoming out on the nut that's used to secure the stem onto the wheel, before it could be set far enough down for the bowden cable to work with an air chuck.
I observed that the nipple in the Schrader valve of the valve stem stands nearly flush with the end of the valve, but with th Air Flexx installed the cable was recessed about 3mm, too deep to be engaged by the air chuck. Taking 2-3mm off the bottom of the Air Flexx brought the cable just a hair below flush and now it works with a chuck. I have since put the DS1 on the Air Flexx and it also works so I'm satisfied. I'll take a picture of one of my plain valve stems in the morning.
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