TPMS Accuracy question

[JSolo]

So tl;dr, after tire rotation, system will automatically learn new sensor positions after driving the car over 15mph for upto 20 minutes (per kgis). Of course it goes without saying that front/rear pressures need to be adjusted accordingly. Is the auto learn expectation correct?

I use a husky gauge connected to the compressor - Husky Digital Tire Inflator and LED Gauge-HDDTI90 - The Home Depot . It reads in .1 psi increments. What I have found is after making adjustments (add/remove air), it takes a little time for the display to stabilize/settle the reading.

Appears to no longer be available. An updated mode Freeman Digital Tire Inflator with LCD Pressure Gauge-FATDTI - The Home Depot looks to have identical specs.

For long trips I take with a rope type plug repair kit and this compressor. It runs off the battery and is quite potent.

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[Wilzer]

Do the TPMS provide the pressure values accurately or is there a difference of +/- 2-3 psi?
I though i was filling 36 and 38 psi respectively, on pretty much cold tires (gas station is 500 m from my place), and the TPMS was showing 41-42 psi all around.

If possible, avoid gas station and other ambient air filling. The reason for nitrogen is the "gas" is dried before compression, SCUBA air works great too if you have access (not nitrox).. The moisture in the tire creates corrosion at the tire bead and starts to leak air slowly, wasn't problem for our forefathers when they used innertubes in tires, but we inherited a problem. The gas stations like it, it keeps you coming back. Went to a high end tire place with my last car when I had slowly leaking tires and they explained it to me, unmounted the tires and cleaned the beads and used dry gas to fill, and that was the end of the problem. I'm a diver, so I have 80% dry nitrogen (the normal air we breathe) to fill my tires, top them off about once a year.

 

[RM7]

Yes, TPMS is notoriously inaccurate. It's good for an "idea", but not accurate within more than a few PSI usually.

Really, there's a lot of variance in pressure gauges. Most are reasonably precise. Few are precise AND accurate.

 

[RogueIV]

Mine like to continuosly bitch about the pressure being low in a tire even when it's inflated right so my faith in the system isn't exactly glowing. I'm too lazy to overinflate my tires just to reset the system.

 

[RogueIV]

So tl;dr, after tire rotation, system will automatically learn new sensor positions after driving the car over 15mph for upto 20 minutes (per kgis). Of course it goes without saying that front/rear pressures need to be adjusted accordingly. Is the auto learn expectation correct?

Yes, the TPMS will autolearn new sensors, as long as they are the proper kind.

 

[JSolo]

New sensors? They reused mine after attaching new valve stems. Why? Don't know.. Told the kid the car is brand new. He insisted, said it was policy. Oh well. I did get 1 mismatched valve cap out of it. Pressure were somewhat uneven so I topped it all off to 39 psi. Will adjust tomorrow morning after it's cooled down.

 

[RogueIV]

New sensors? They reused mine after attaching new valve stems. Why? Don't know.. Told the kid the car is brand new. He insisted, said it was policy. Oh well. I did get 1 mismatched valve cap out of it. Pressure were somewhat uneven so I topped it all off to 39 psi. Will adjust tomorrow morning after it's cooled down.

Yes, even aftermarket ones pair fine.