Tire Pressure Measurement Problem

[kaneohe]

Anybody ever had this problem. Replaced 4 tires a few wks ago. After replacement at Costco, set and measured tire psi myself.
Those little things on the valve stem that work with the car's tire monitor systems were also replaced. Measured tire psi a couple wks later.....they were slightly lower than expected but the more troubling thing was that there was a 2.5 psi variation from high to low.

Thinking that there might have been a small leak from installation on a rainy day and hoping it might have fixed itself, I refilled again and remeasured immediately after refill.
Today a week or so later, the first 2 tires read 25 psi, a bit of a shocker since I was expecting 35 or so. The next 2 tires read 34 psi. I went back and re-read the first 2 tires and now they read 34. Is that a tire measurement gauge going bad, or a one-time intermittent problem caused by what?

 

[braumeister]

The TPMS sensors are irrelevant in this case.
Appears to be simply a case of your not always having a good attachment of your gauge. Be cautious to always apply it straight on the stem, not canted even a little. That should solve the consistency problem. You might also consider buying a better quality gauge. That can also help.

 

[Jerry1]

Agree, if you're going to measure something, make sure you have a good gauge and are doing it correctly. Also, don't forget that as it gets cold, the tire pressure will drop. Always check your tires after the car has sit for awhile and the tires have cooled down - first thing in the morning. As I drive to work on a cold day, my tires can change (increase) in pressure by 3-5 psi.

 

[kaneohe]

The TPMS sensors are irrelevant in this case.
Appears to be simply a case of your not always having a good attachment of your gauge. Be cautious to always apply it straight on the stem, not canted even a little. That should solve the consistency problem. You might also consider buying a better quality gauge. That can also help.

Never had this problem in many yrs w/ this same gauge.Usually the problem
(same as what you're describing, I believe) is that air hisses out of the tire w/ a bad alignment of the gauge. The gauge is a 2" round type of reasonable quality tho possibility age is showing? Good to know the TPMS sensors are not relevant. Thanks for info.

Edit to add: before I changed tires, I could go months w/o refilling tires as decrease in psi was "reasonable" over time
and variation between tires, while always present, was "small" and part of the measurement noise.

 

[Walt34]

If I saw variation like that I think the first thing I'd do is buy a new gauge. They don't cost that much. Come to think of it the one I have I bought when I bought the new pickup truck. They're both 15 years old now so it probably would be a good idea to get a new gauge.

 

[aja8888]

TPMS sensors are relevant as DW had them rebuilt on her 2013 Santa Fe and the dork that rebuilt them (cup style synthetic sealing ring replacement) put two of the four sealing rings on upside down causing slow leaks in those tires. The tire shop had to unmount the tires and take apart the sensors and reverse the sealing rings.

 

[kaneohe]

If I saw variation like that I think the first thing I'd do is buy a new gauge. They don't cost that much. Come to think of it the one I have I bought when I bought the new pickup truck. They're both 15 years old now so it probably would be a good idea to get a new gauge.

Was just looking on Amazon......and noticed all the gauges seem to have an angle built in at the end......both the gun type digital types and the round analog gauges. Maybe it's just a mental block but I used to have lots of trouble sealing those pencil gauges w/ that sort of angle. Things got much better when I got the round analog w/ no angle at the end so ever since I've been gun-shy about angles there. Do they still make the analog types with no angle at the seal end?

 

[Walt34]

Do they still make the analog types with no angle at the seal end?

Probably, but you might have to look for it. I had one for the motorcycle that I bought in 2009 but when I sold the bike I gave it to the guy who bought it.

 

[Sunset]

I had a round one, and it was old, found out it was reading 4 lbs lower than it should.

I bought a new round analog one without the angle end.

I totally avoid the stick ones where the little stick pops out, as it seems to me dirt will get in and interfere with the stick.

Mine looks like this, with the pressure release button, but a different brand.

 

[kaneohe]

Thanks for that pic.......was really looking for a link but putting that nice brand name in Amazon produced one that looks very similar.

 

[easysurfer]

Yes, get a good gauge. Sometimes old fashioned is the best way to go.

The one I have doesn't lose any air when placing on the stem. Otherwise, defeats the purpose of measuring. The one I have is pretty large (I also got the protective cover for the gauge too), but very reliable when called upon .

https://www.amazon.com/Moroso-89560-Tire-Pressure-Gauge/dp/B000COS8FI

 

[Clone]

I used to have a picture for one that was advertised as a 'Radial Tire Pressure Guage.' In small letters near the bottom it said 'also works on bias tires.' That would probably not mean anything to many younger folks, but back in the day having radial tires was a big deal!

Over the years, we have gone through many of the cheap stick type gauges. Part of the challenge comes with trying to read 12 psi on tractor tires, and 110 psi on the front tires of a semi. The little low pressure gauges get really upset when you honk 100 psi at them!

I have always thought about making up a four tire air line with the schrader valve fittings like an Amflow 556. And then a decent air pressure guage plumbed into the line.

 

[Bamaman]

I have two cars with ultra low profile high-performance tires. I cannot keep air in them very along. They leak in pairs, and I finally bought a portable small compressor as my big compressor weighs 100 lbs. This week, both cars were sitting on the rims.

My new Camry Hybrid has normal tires as does my pickup truck, and air pressure remains stable in them.

 

[Mr._Graybeard]

TPMS sensors are relevant as DW had them rebuilt on her 2013 Santa Fe and the dork that rebuilt them (cup style synthetic sealing ring replacement) put two of the four sealing rings on upside down causing slow leaks in those tires. The tire shop had to unmount the tires and take apart the sensors and reverse the sealing rings.

Yes. The TPMS seals can also get old and hard, resulting in slow leaks.