Tire Pressure Monitoring System TPMS

There are lots of aftermarket automotive TPMS systems available for cars, trailers, motorcycles etc but most I've read about have quality issues. Has anyone found a product that consistently works good on aircraft? Possible issues could be temperature (some have a temp limit of -20C), tire balance, causing a leak in an otherwise good tire. One system shuts down when after a while of no wheels turning. That's not gonna work.

I'm not so concerned about a tire going flat while airborne (although it's possible and I would like to know before touchdown), I'm curious about tire pressure changes with altitude, temperature and just with the aircraft weight off the tire. TPMS would also be a more convenient and hopefully accurate way of checking tire pressure without have to mess around with wheel pants.

By the way, I have learned not to top up a tire immediately prior to flight because if the shrader (sp?) valve doesn't seat properly, and you don't notice the faint sound, or check with soapy water (who does that?). the tire will leak down during flight. There's not much air in our tires so a leak doesn't take long to be critical.

Bevan

Tire Pressure Monitoring System

See Aircraft Spruce website for "TIRE PRESSURE MONITOR".

I haven't used it but did talk to the engineer who designed it for aircraft.

My 'monitor system' is the feel as I pull the RV out of the hangar. Any resistance and I know I have low pressure somewhere. I typically check pressure for 42 pounds about every month-6 weeks by pulling pants and having a look at tires also.

One flat away from home with no tools/spare is enough for a lifetime!!!!

valve cap

After filling the tire, I put a little spit on my finger tip (I'm an ol' farm boy) - then put my finger tip over the valve stem. No bubbles - then the schrader valve is probably not leaking. I also use 2525 valve caps for extra insurance.
http://www.aircraftspruce.com/catalog/lgpages/valvecap.php?clickkey=13021

I have a TPMS for sale if anyone wants it. IMHO it sucks. Very hard to remove to put air in tires. Not sure what you gain with it anyway.

options????

A fellow on our field had the TPMS and seemed to like it ok. He sold the RV so not sure how to get his opinion.
I was concerned that the big caps would hit something in the wheelpant....but I guess that was not a big concern.
I was leaning toward the little caps that just show a single pressure, say 38 for the mains, and 32 for the nose, or whatever you run...you'd only need to line up the stem with the hole, preflight, to verify the pressure.
...... if it's low, the sleeve turns yellow, but that might be hard to see?

at less than $10 each, might be worth a try.

....Bevan, I thought it was 18C there year round anyway, why would the pressure change?

A bit of drift, but I just got one of these to top off my tires and carry with me on flights or drives in my car. It works reasonably well and if you have the Ryobi system drills, it only cost $20. It is very light too.

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building a good system is no problem electronics wise. the problem is that we use very small tube tires. no way to put a sensor inside the tube. that leaves using a pressure sensor between the tube and the tire or the rim. not the best and most accurate way to sense tire pressure.

bob burns
RV-4 N82RB