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Doug G.

Tire Pressure Monitor

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Hi everyone. I am wondering if anyone had used an electronic tire pressure monitoring system on a CT. We have talked about how it is possible to roll a tire on the rim if pressures get low. It seems this would help that situation.

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I have installed them Doug.  Extremely convenient. I can now check tire pressure on all three wheels with the remote reader.  Recommended to me by current owner of Adam's former plane.  They are not inexpensive though. 

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Also, if you use leakguard tubes, it is very likely that the sensors are incompatible. Leakguards are AMAZING tubes anyways, so I would prefer those over a TPMS.

 

EDIT: Doug has verified that there is no liquid tire sealant inside the leakguard tubes, which was my concern that the substance would not be compatible with TPMS systems.

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I said they are likely incompatible. I pointed that out because you should verify it.

 

My theory is that the leakguard substance in the tube (they come with a little bit of that nasty green stuff right?) would not mix very well with the sensor cap (I imagine this is the little screw on valve cap type). I know that TPMS sensors in cars do not like that green stuff, so I wanted to make sure you don't end up ruining an expensive TPMS system for your plane.

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If we are talking about the Desser tubes, I think they are just heavier tubes. I never saw anything about any substance inside on the Desser sight, or any warning in the package.

With looking into though, but I am being someone here knows. :-)

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Dropped a note to Desser to ask about the Leakguard tubes and liquid sealant. Here is the reply.

 

Hi Douglas,

 

That is not true.  The Leakguard tubes are butyl compound like Goodyear and Michelin’s.  There is no liquid of any type.

 

Best regards

 

Steve

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Awesome!

 

Better to have checked and verified compatibility, than to find out the hard way if it wasn't compatible! :)

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I have been using the motorcycle for two years. It has really helped. With multiple people using the airplane we had been getting flats because of low air pressure. Now the can see the pressure on pre flight and no more flats.

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I have read that in some iterations, tire pressure monitor sensors like the type we're discussing can be prone to sudden failure.

 

Since that can have drastic consequences, I think that is the concern.

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How hard is it to look at your tires during preflight to verify they are properly inflated?  If they look low, check the pressure and put some air in.

You have not been around CT's much. The small tires always look low, and they are a bear to check with the wheel pants on.

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I can't see how changing valve caps would require a MRA. That is basically what is happening here.

Because it's still changing an airframe part, or altering one if you look at it from the inner tube perspective. I highly doubt anyone would care though unless it failed.

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One hint from the Cirrus world...

 

Inflate the tire properly, then trim a piece of wood or plastic so it exactly fits between the wheel fairing and the ground.

 

If it fits, you're good to go. If not, you have some vague indication of how low it is.

 

Oh, and one more...

 

Move the plane so the valve stem is where you want it, and put a bright spot or line on the tire at that point. I just used yellow paint. Then it's easy to push or pull the plane until the valve is in the right place.

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Because it's still changing an airframe part, or altering one if you look at it from the inner tube perspective. I highly doubt anyone would care though unless it failed.

You don't need a MRA to change airframe parts, and I wouldn't consider that altering the tube.

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One hint from the Cirrus world...

 

Inflate the tire properly, then trim a piece of wood or plastic so it exactly fits between the wheel fairing and the ground.

 

If it fits, you're good to go. If not, you have some vague indication of how low it is.

 

Oh, and one more...

 

Move the plane so the valve stem is where you want it, and put a bright spot or line on the tire at that point. I just used yellow paint. Then it's easy to push or pull the plane until the valve is in the right place.

Unless you modify the wheel pant it needs to be loosened or removed to check pressure. Trimming the piece of wood might work if you have a nice smooth hangar floor, and the tires don't wear. There is almost 3/16" difference between a new tire and one that needs replaced.

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Fine.

 

But don't let the perfect be the enemy of the good.

 

Works well enough for most purposes, especially since gauges are not perfect either.

 

Nor are tire pressure monitors.

 

Checking pressures on the Cirrus was a pain as well, but doable with a properly angled chuck - checking mine was on my monthly checklist and just not that big a deal.

 

Not to say the CT might not be worse.

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As long as we are on the subject of tire pressure, what pressure do you like to use? The book says 28 but that is way too low and easy to get flats. I went to 36psi

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You don't need a MRA to change airframe parts, and I wouldn't consider that altering the tube.

You do need an MRA to change airplane part if they didn't come with the airplane, or are not standard equipment. Hell, FD has to approve the tires if it's a brand they have not used or approved yet (PMA doesn't apply to LSA).

 

Tube caps are pretty important for the tube's integrity. They are thread-on because they help act as a backup for the schrader valve, and keep dirt out.

 

If you were replacing the cap with the same cap part, you wouldn't need an MRA, but you are replacing it entirely with a functionally amended model that you are also relying on to read out tire pressure.

 

Also, how does it read said tire pressure through the schrader valve? It would need to open the valve, and hold it open, in order to take readings. That's a pretty MAJOR change to the intented operation of an inner tube.

 

That said, I doubt you are going to get stopped on a ramp check and get violated if they saw the TPMS sensors, but of course the FAA will cover their ass if someone gets hurt with those on.

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What about the valve within the stem, can you change that without an LOA?

I know for certain that you cannot suction cup a camera to the outside of your plane, and to use a permanent stud definitely takes manufacturer (and/or FAA) approval. (Check out page 29 of the Jan./Feb. FAA Safety Briefing magazine.)

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