So, you are wondering how to calibrate a tire pressure gauge. The instrument has become terrible from wonderful in just a few days by offering incorrect PSIs or bars.
A Tire pressure gauge is a useful instrument for detecting the air pressure of different tires. It can do wonders with its accuracy but can be equally disgusting with its misreading if it hasn’t been calibrated for a long time.
Many of us wish to possess a tire pressure gauge for the benefits it offers while driving. At the same time, every pressure gauge needs calibration at a certain point and it’s kind of surprising to learn that the information on the calibration process is very limited and confusing.
This is why I am writing this post to help you know and understand the calibration process and methods to test the accuracy of a tire pressure gauge.
How to calibrate the tire pressure gauge?
A tire pressure gauge can be efficiently calibrated or re-calibrated by the manufacturer or official service partners of the instrument. This is the best and most reliable way to calibrate a tire pressure gauge once in a year.
For some reason, if you do not want to comply with the calibration process from the manufacturer the best alternative is a replacement.
To know if your tire pressure gauge requires calibration there are a few ways that can be performed onsite with the help of some instruments. This includes using a manual pressure hand pump, a tire pressure monitoring system, and a hose pipe.
Pre-requisites while purchasing a tire pressure gauge
Purchasing a new tire pressure gauge should be done with proper research and the best knowledge. Follow the guidelines and tips from someone who is already using such products or from the information you get online.
Keeping the buyer’s guide factor aside, one of the important pre-requisite which I personally recommend doing is pre-checking or measuring the existing tire pressure before purchasing a product.
This can be done by taking your vehicle to your regular garage or a service station just to get an idea of the tire pressure.
Note the PSI numbers so that they can be compared with the new product you want to buy. Once you have finalized a gauge, test its accuracy by checking the air pressure on your vehicle tires.
A marginal difference between 1 to 2 psi should not be a concern. If anything more than this, it is better to reconsider your buying decision.
Having said that, most tire pressure gauges (of any type) are pretty accurate when they are brand new.
The problem arises when these products are frequently used or have crossed the deadline for re-calibration recommended by the manufacturer.
It won’t be long to find discrepancies in the pressure reading and wrong estimates provided by such units.
So, what do you do?
Official re-calibration
As I said earlier, the best way to calibrate/re-calibrate a tire pressure gauge is to get it re-calibrated by the manufacturer itself. Every manufacturer recommends performing re-calibration once every year.
To do this, they have specified equipments such as a calibration machine and a dedicated process that re-linearizes the whole equipment according to the calibration regulations.
The advantage of re-calibrating through the manufacturer or a recognized calibrating partner is the achievement of traceable calibration certification which is a token of accuracy assurance.
On the flip side, the re-calibrating services may not be always free unless covered under warranty by the manufacturer.
Ways to test the accuracy of a tire pressure gauge
Manual air pressure pump
One of the effective ways to test the accuracy of a tire pressure gauge is by using a manual air pressure pump.
To use this method, you will need an extra set of digital pressure gauges (already calibrated or new ones) to measure and compare the readings.
The testing cannot take place without its major player i.e. a hand air pressure pump. It should basically have two open ends to fix the pressure gauges.
Here is the step-by-step method:
- Connect the digital pressure gauge to one end and the pressure gauge that needs testing to the other end of the pressure pump.
- Close the air escape valve (if any) of the pressure pump to ensure no air can be leaked while filling the pump.
- Turn on both pressure gauges for testing the accuracy and set a specific PSI in the digital pressure gauge.
- Once everything is set and connected, start adding pressure slowly by pressing the levers of the pressure pump manually.
- As you continue to add pressure, it will start capturing the psi/bars in both pressure gauges. Once the pressure reaches the targeted PSI on the digital pressure gauge compare the psi units appearing in the testing gauge as well.
- If the reading is the same or very close to each other that means the testing pressure gauge is working fine. But, if there is too much difference or variations (more than 2 psi) between the two it is time to calibrate the pressure gauge.
Here’s a small video on using a pump tool to test the pressure gauge:
TPMS comparison
Using a Tire Pressure Monitoring System (TPMS) is another solid way to test the accuracy. Here, you will need a working and accurate TPMS and your tire pressure gauge.
First, replace the valve stems of the tire with TPMS sensors
Next, set the PSI on the TPMS and turn on the gadget to check the tire pressure.
Now, replace the TPMS with the tire pressure gauge. Insert the air chuck into the tire and take the reading.
If you find the reading to be accurate between a margin of 1 psi to 3 psi with the TPMS the difference is not a big deal. A major discrepancy in readings is an indication that your pressure gauge needs re-calibration.
Related Read: Do tire inflators drain battery?
Hose pipe
The hose pipe method is one of the unorthodox ways to measure and test the accuracy of a pressure gauge. The method is result-oriented however I am not a big fan of it as it requires lots of effort, material, and space.
With a hose pipe lengthing 25 meters and an equal number of floors in a building, you have to keep adding water in the hose pipe and measure the accuracy of a pressure gauge.
If you are interested in knowing complete details about the hose pipe method then here is the link.
Final thoughts
Accuracy of tire pressure is equally important to keeping a tire pressure gauge as a device. It is senseless to use a tire pressure gauge that is inaccurate and needs calibration.
Gauges providing wrong readings on tire pressure lead to the risk of driving on underinflated or overinflated tires. Both scenarios are responsible for tire blowouts and lead to accidental consequences.
To avoid the dangers of running on unbalanced tires it is well recommended to carry a tire pressure gauge that is correctly calibrated and displays accurate air pressure.
It is important to re-calibrate the tire pressure gauges once a year or as recommended by the manufacturer. There are methods to detect the inefficiencies and inaccuracy symptoms of tire pressure gauge that you can find in this post.
Follow the guidelines and information to keep the pressure gauge well-maintained and follow the calibration regulations to calibrate them according to the manufacturer’s instructions to remain protected from tire abnormalities.