TPMS vs Gauge

I have had two different TPMS systems and have found the pressure they read out to be within 2 psi of my pressure gauge.


While traveling I watch for a tire pressure that is much different from the others. After about 10 miles of towing I find all four of my trailer tires are usually within 2-3 psi if they were all the same before the trip.

I had one that was about 5 psi lower than the other 4 on my trailer. I pulled over at the next gas station and found a 3/8 x 2 inch machine bolt in the tire that was indicating low. The TPMS saved me from having a total tire failure which surely would have damaged the trailer.

The TPMS may not agree with a high quality pressure gauge but what is important is the TPMS is usually consistent and will let you know if a tire is losing pressure while under way.

Also more convenient to check pressures early in the morning before each trip.

If the question is which do I think is more accurate I go with my digital. When I have the exact same pressure in two tires using the digital and the TMPS shows a couple of lbs difference I believe the digital.

However, I do not sweat 5 lbs one way or the other and tend to add 5 lbs to the door sticker when filling cold tires. I noticed over the years that my tires tend to wear on the edges and not evenly if I only put in the door sticker PSI. When I add the extra 5 lbs the tires wear evenly across the tread.

I have 4 digital and they will all read within .5 lbs of each other.

Yes I have been anal enough to see if they all read the same and I think the .5 lbs was the little air that leaks when you put on and take off the gauge.

I also have several analog gauges and those I do not trust except to be within 3-4 lbs of accurate.

If you really want to be dead nuts build A water column gauge! It only needs to be 2500" tall!

The gauge is an analog unit. Tomorrow I'll dig out my digital and see how it matches up.

Thanks for all the comments.

Ron

"Now, as far as the accuracy of the tire pressure monitoring system (TPMS) is concerned, the internal tire pressure sensors are relatively accurate compared to your typical $2 gas station tire gauge (+ or - 1psi according to Johnson Controls, which makes millions of OEM TPMS sensors)."

From google.

I use my TPMS over any gauge which seem to be off as much as 5 psi from the TPMS

The whole issue of accuracy of ALL TP gauges is unacceptable. Time for a trustworthy TP gauge for the masses.

You can use 5 different gauges and probably no two will completely agree on every tire.

Using a TPMS to check the tires before driving sure beats eye-balling or mechanical gauge.

I go 5 over what my weights require as I'll still drive with a good cross wind that shifts a lot of weight to the down wind side. You will see a 10 percent increase in the pressure even on a cool day once you've gone 15 miles. On a hot day it could be 15 percent.