TST malfunctions???

Grey Ghost

Well-known member
I didn't know where to place this so thought I would try here and see what type of response I got. Anyhow, I air my tires up before each trip at Discount Tire and ck them during the trip before leaving each campground. The guy at Discount said he put 80psi in each tire, but when my monitoring system comes on line the pressure varies from tire to tire by anywhere from 2 to 8 psi, is that normal? How much off can these systems be and still be safe? If one says 80 psi and another shows 75 psi should I be concerned? I thought these systems were supposed to be pretty accurate.
 

danemayer

Well-known member
Hi Grey Ghost,

There are two possible explanations: 1) the sensors are inaccurate, or 2) the tire guy wasn't as precise as you want him to be.

You might buy a good tire pressure gauge and check the tire pressure independently of the TPMS sensors. Then you'll have a better idea of which explanation to go with.

Btw, my gauges don't agree with one another, or with the TST sensors. But they're all within 5 psi when I've inflated the tires to 110 psi. And all the gauges and sensors are pretty consistent from tire to tire.

On edit, it's also possible that some tires are in the sun and are reading higher than the others.
 

pegmikef

Well-known member
My money is probably on the tire guy. I use a viair 450p compressor and its gauge to fill my tires to 110 and then check each tire with a separate gauge to make sure they are at 110 psi. After I put the sensors back on my readings are within one or two pounds of each other and like Dan's, that delta stays constant. I have learned from experience that my fill gauge is two psi low so I account for that when I fill the tires.
 

porthole

Retired
Whose tire monitor?

Airing up at Discount tire - how far are you driving to air your tires?

My TST system typically reads from 0-2 pounds of what I put in compared to my Powertank pressure gauge.
https://powertank.com/products/sfID1/14/productID/368

Too many variables to consider - compressor volume tank full at the start, or just turned on for the morning and the compressor ran for 10 minutes (heating up the air even more). Many shops shut down the compressor at night because of leaks.

I doubt the guy at Discount is using a $100 1% gauge to check your tires.


If one says 80 psi and another shows 75 psi should I be concerned?

Simple answer - YES
 

SilverRhino

Well-known member
I use the same set up as Duane.....with the same results and would agree with everything he said about variables and when to be concerned.

My TST system typically reads from 0-2 pounds of what I put in compared to my Powertank pressure gauge.
 
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