Gloom, despair and valve stems

[poihths]

My valve stems are driving me nuts. Let me try to present a sane presentation of this insanity.

It's a 2018 Leprechaun FSS-31 built on Ford E450 chassis with Hankook Dynapro tires. The rig is new to me as of January. I'm new to RV's. This rig has dual rear wheels.

The dealer, at our request, installed a TSTTruck tire pressure monitor that uses sensors screwed onto the valve stems such that you can add air through the sensor. Each of the six valve stems have one of the sensors screwed on.

On the front tires, the hubcaps cover the sensors & valve stems so that I can't get the connector from my compressor to screw on. Trying to maneuver the stem to get access causes air to come hissing out. I think it's coming from the connection between the sensor and the stem--too much strain on that joint. It would work if it weren't for the sensors but I can't get the sensors off because the hubcaps are in the way and won't let the sensors turn.

On the back tires, I can get at the outer stems but not the inner ones. The inner stems are visible through the holes in the hubcaps but I can't get at them. I might be able to do some good if I could get at whatever hardware is between the inner and outer wheel but I can't reach around in between the tires because I can't get my hand through the gap between them.

I stupidly let the batteries on the monitor system go dead over the winter. It seems to have completely lost the installation setup. Restoring the setup requires touching each sensor to the CPU. That seems to require removing the sensors. As described above, in four of the six cases I can't get the sensors out.

So, at present, I can't measure tire pressures and I can't add air. That's neither good nor sustainable.

The only way I can see to attack this is to take the hubcaps off. That looks very dangerous to me. I don't have a hoist and even if I did I don't think I could out-wrestle the wheel if it tried to come off. Those gigantic wheel nuts were surely put on with pneumatic tools. I haven't been hale, hearty and 20 in 48 years; there's a quadruple bypass in my chest. I don't think I'm going to win that battle.

It looks to me like the only strategy available is to throw money at the problem.

Am I missing something? I am perfectly willing to erect a ritual pyre and sacrifice a spotless young ewe.

[bubbles]

I think those gigantic wheel nuts are part of a wheel liner and only 2 or 3 come off to remove the liner. The gigantic nuts cover the actual lug nuts. The liners are thin stainless steel.

[wmtire]

Can you take some pics of all this. The front tires should have had the stems aligned with a hole in the hubcaps for the stems, that allows air to be added/checked. The person who put the TPMS on, may have not paid attention to this when reinstalling the hubcaps.

[poihths]

Here's a picture of the front wheel. Yes, that valve stem, actually the sensor, looks like you could just hook right up to it - but appearances deceive. But if I could get that wheel cover off....

[poihths]

And here's the back cover.

[bubbles]

There should be 2 covers with the indent as shown. Remove those and the cover will come off. Same with the back but may be 3 to remove.

[camper_Lucy]

use these to simplify your life on the duals,
https://www.amazon.com/Crossfire-Dua...0030414I&psc=1

on the fronts have them use 90 degree stems. similar to these
https://www.amazon.com/VPro-Brand-Gl...%2C134&sr=1-20

[dieselguy]

One of the advantages of dual tires is if one goes flat ... you have another to limp you on to a place to get it fixed. The equalization lines linked above seem to nix that advantage as when one tire goes flat ... both will. Or ... am I missing a reverse flow valve or something as I've never contemplated linking my two duals together as such.

[poihths]

Per Bubbles' tip I looked for nuts/covers with indents on them and found none. It seems like the whole hubcap is one unit. When I grab the rear one using the cylindrical shape in the center, it seems like I can make the whole hubcap wiggle and bend.

So am I looking at something that I pry off under the edges?

[DougW]

Looking at the picture of the front wheel, I see a scalloped section at about 1 o’clock of the wheel. If that were to be put at the valve stem your problem might be solved.

[fobagbob]

Originally Posted by poihths

Per Bubbles' tip I looked for nuts/covers with indents on them and found none. It seems like the whole hubcap is one unit. When I grab the rear one using the cylindrical shape in the center, it seems like I can make the whole hubcap wiggle and bend.

So am I looking at something that I pry off under the edges?

Some are held on with nuts as described above but some are not. If you are able to wiggle the hubcap, then yes, pry them off and then you can figure out a solution with extensions that will allow access without removing the hubcaps.

[poihths]

And it worked. Gentle, persistent persuasion with a mallet and a cold chisel got the wheel covers to pop off without any damage. I now know how to get access to the stems and sensors to do what I need to do. Thanks, everybody!

[Mikeytheb]

I have these - have not experienced it, but manufacturer states only one will go flat if that happens.

[ChrisParise]

Whom ever installed your TST TPMS was incompetent

Ideally, you should have metal (brass and chrome plated) bolt in valve stem extenders on all 6 tires.

Your front extenders need to be 2 1/4" long prebent at 20 degrees. They will support your sensors and easily allow you to add air.

Rear inners need to be straight and 8" long. Outers should be bent at 135 degrees

Look at your TST manual if the rear inner sensors can be mounted on braided steel extenders filled with air all the time, some have a wire which when the air chuck is on will press on the rubber valve stem to get pressures and these may not work with your sensors. You'll still need 135 degree valve stem extenders for your outers

Any truck tire shop should be able to install these, probably your rv chassis shop too

[BMullins46]

Simple solution, TAKE IT TO A TIRE SHOP. It may cost you a few bucks but you'll get your problem fixed.

[MevetS]

Per TST Flowthru sensors are to be used only on metal valve stems. That makes sense, IMO. You don't want a pendulum for a valve stem. They will cause a failure.

Same goes for valve stem extensions. Don't use them, they will also fail. Use only metal valve stems. Have a competent Tire shop, that deals with dual tire system on a frequent basis. Have them align the appropriate metal valve stems so that they are 180° across from each other, on the dual rear tires. Makes life less stressful and it's easier to change the batteries in the sensors.

[ChrisParise]

Originally Posted by MevetS

Per TST Flowthru sensors are to be used only on metal valve stems. That makes sense, IMO. You don't want a pendulum for a valve stem. They will cause a failure.

Same goes for valve stem extensions. Don't use them, they will also fail. Use only metal valve stems. Have a competent Tire shop, that deals with dual tire system on a frequent basis. Have them align the appropriate metal valve stems so that they are 180° across from each other, on the dual rear tires. Makes life less stressful and it's easier to change the batteries in the sensors.

[emoji106]

[MF5270]

Originally Posted by poihths

My valve stems are driving me nuts. Let me try to present a sane presentation of this insanity.

It's a 2018 Leprechaun FSS-31 built on Ford E450 chassis with Hankook Dynapro tires. The rig is new to me as of January. I'm new to RV's. This rig has dual rear wheels.

The dealer, at our request, installed a TSTTruck tire pressure monitor that uses sensors screwed onto the valve stems such that you can add air through the sensor. Each of the six valve stems have one of the sensors screwed on.

On the front tires, the hubcaps cover the sensors & valve stems so that I can't get the connector from my compressor to screw on. Trying to maneuver the stem to get access causes air to come hissing out. I think it's coming from the connection between the sensor and the stem--too much strain on that joint. It would work if it weren't for the sensors but I can't get the sensors off because the hubcaps are in the way and won't let the sensors turn.

On the back tires, I can get at the outer stems but not the inner ones. The inner stems are visible through the holes in the hubcaps but I can't get at them. I might be able to do some good if I could get at whatever hardware is between the inner and outer wheel but I can't reach around in between the tires because I can't get my hand through the gap between them.

I stupidly let the batteries on the monitor system go dead over the winter. It seems to have completely lost the installation setup. Restoring the setup requires touching each sensor to the CPU. That seems to require removing the sensors. As described above, in four of the six cases I can't get the sensors out.

So, at present, I can't measure tire pressures and I can't add air. That's neither good nor sustainable.

The only way I can see to attack this is to take the hubcaps off. That looks very dangerous to me. I don't have a hoist and even if I did I don't think I could out-wrestle the wheel if it tried to come off. Those gigantic wheel nuts were surely put on with pneumatic tools. I haven't been hale, hearty and 20 in 48 years; there's a quadruple bypass in my chest. I don't think I'm going to win that battle.

It looks to me like the only strategy available is to throw money at the problem.

Am I missing something? I am perfectly willing to erect a ritual pyre and sacrifice a spotless young ewe.

I'd go to a tire shop and have them install proper stems. Then go to Costco and have them converted to nitrogen.
Neither will be expensive.

[Tireman9]

Originally Posted by dieselguy

One of the advantages of dual tires is if one goes flat ... you have another to limp you on to a place to get it fixed. The equalization lines linked above seem to nix that advantage as when one tire goes flat ... both will. Or ... am I missing a reverse flow valve or something as I've never contemplated linking my two duals together as such.

The primary reason for dual tires is to support the load on that axle. One tire can not support the load. If one tire in a dual goes flat (leaks) or fails, you now have the "good" tire in a 100% overload situation so driving on it for more than a couple miles needed to get off the interstate you are doing serious permanent damage to that tire so it would need to be replaced also.


Best is to have a TPMS so you get an early warning of air loss on one of the duals.


People pushing (selling) the dual "equalization" system almost never point out the problem of one tire getting a puncture and loosing its air pressure. The UN-punctured tire sends 10% of it's air to the punctured tire so even before the punctured tire goes flat and transfers 100% of its load to the "good" tire you are running the "good" tire underinflated.

[Bramic71]

Dremel.