Every responsible motorist knows that the condition of the wheels directly affects driving safety, fuel consumption and suspension wear. However, just a visual inspection is not enough to maintain perfect condition; It is necessary to regularly monitor the air pressure inside the tire. Many drivers, especially beginners, wonder: what is the name of the device for measuring tire pressure and how do different models differ from each other? The answer is simple - this tool is called pressure gauge, but in the world of automotive service there are many modifications of it.
Using the right tool can help you avoid serious problems such as uneven tread wear or, worse, high-speed tire tearing. In this article we will analyze in detail the design of pressure gauges, their types, operating principles and learn how to correctly interpret scale readings. Understanding that What is the name of the device for measuring tire pressure? and how to use it is a basic skill that every vehicle owner should have.
The modern market offers a huge selection of diagnostic equipment, from simple mechanical models to high-precision digital devices. Understanding this diversity can be difficult without preparation. We'll go over the key features of each type so you can choose the right tool for your garage or glove compartment. The accuracy of the readings is not just numbers, it is your safety on the road.
Main types of pressure gauges for cars
Today, there are three main types of devices that are used to measure pressure in vehicle pneumatic systems. The most common and time-tested is mechanical (pointer) pressure gauge. Its design is simple and reliable: inside the case there is a springy metal tube that is deformed under the influence of air pressure. This deformation is transmitted through the gears to a hand indicating the value on the dial. The main advantage of such devices is their autonomy - they do not need batteries, and they work at any temperature.
The second popular type is digital pressure gauges. They are equipped with an electronic pressure sensor and a liquid crystal display. Such devices often have increased accuracy and allow you to switch between different units of measurement (BAR, PSI, kPa) with the touch of a button. However, digital electronics are more sensitive to severe frosts and require periodic replacement of batteries. Despite this, many professionals prefer them for the ease of reading data.
The third type is rack and pinion pressure gauges, which can often be found in the form of key chains or bundled with pumps. The principle of their operation is based on the movement of calibrated slats under spring pressure. They are compact and cheap, but less accurate compared to pointer and digital analogues. The choice of a specific type depends on your requirements for accuracy and operating conditions.
- 🔧 Mechanical pressure gauges are reliable classics that do not require power and are shock-resistant.
- 🔋 Digital devices - high accuracy, screen backlighting and the ability to change units of measurement.
- 📏 Rack and pinion models are compact and low cost, but have less durability of the spring mechanism.
Units: BAR, PSI and atmosphere
When purchasing or using a device, it is important to understand in what units it measures pressure, since standards vary depending on the region of manufacture of the car and the instrument itself. In Russia and Europe the de facto standard is Bar or technical atmosphere (atm), which are almost equal to each other (1 Bar ≈ 0.987 atm). These are the values that are indicated on the stickers located on the door pillars or gas tank flaps of most cars assembled for our market.
American and Japanese manufacturers often use the unit of measurement PSI (pound-force per square inch). If your pressure gauge shows values in PSI, and you need to inflate the tire to 2.2 Bar, you will have to recalculate. To simplify the task, you can remember that 1 Bar is approximately equal to 14.5 PSI. Some advanced digital models allow you to instantly switch scales, eliminating the need for a calculator.
⚠️ Attention: Never mix units of measurement when inflating wheels. If you are used to BAR and the pressure gauge shows PSI, an erroneous action could cause the tire to be overinflated by 14 times, which could result in a tire explosion. Always check the markings on the instrument scale before starting work.
Also in technical documentation you can sometimes find a value in kilopascals (kPa). This is the International System of Units (SI), where 1 Bar equals 100 kPa. Understanding the relationship between these quantities will help you feel confident with any instrument, be it an old Soviet pressure gauge or a modern gadget from China.
| Unit of measurement | Designation | Ratio to 1 Bar | Where is it used? |
|---|---|---|---|
| Bar | Bar | 1.0 | Europe, Russia, ISO standards |
| Pound per sq. inch | PSI | 14.50 | USA, UK, Japan |
| Kilopascal | kPa | 100.0 | Scientific literature, technical passports |
| Tech. atmosphere | at / kgf/cm² | 1.02 | Old Soviet technology |
If your pressure gauge does not have a unit switch, use a converter app on your smartphone or remember a simple rule: to convert PSI to Bar, divide the number by 14.5, and to convert back, multiply Bar by 14.5.
Design and principle of operation of a pointer device
To understand why the switch pressure gauge considered the standard of reliability, you need to look inside its body. The heart of the device is a tubular spring (Bourdon tube), shaped like an arc. When compressed air from the tire enters this tube, it tends to straighten. This microscopic movement is transmitted through a gear mechanism to the axis to which the pointer is attached.
The most important design element is the damper or flow restrictor. In high-quality models, a special jet is installed at the air inlet, which prevents sharp jumps in the needle when air is suddenly released. This protects the mechanism from shock loads and extends the service life of the device. Cheap analogues often lack such protection, which is why their needle begins to “walk” or sink after several months of active use.
The body of the device is usually made of impact-resistant plastic or metal. Metal cases better protect the insides from external influences, but can be heavier. The dial scale should be easy to read, with clear divisions. Some models are equipped with an additional pointer arrow, which can be manually set to the desired pressure value in order to visually control the inflation process.
- 🎯 Tubular spring is the main sensitive element that converts pressure into mechanical movement.
- ⚙️ Transmission mechanism - a system of gears that increases the stroke of the arrow for ease of reading.
- 🛡️ Protective case - protects the mechanism from dust, moisture and mechanical damage.
Why does the pressure gauge needle tremble?
If the needle vibrates strongly during measurement, this may indicate pressure pulsation (for example, during operation of a compressor) or a malfunction of the damper itself inside the device. In high-quality pressure gauges, vibration is damped by oil filling the housing or special valves.
How to use a pressure gauge correctly: step-by-step instructions
The process of measuring pressure seems elementary, but this is where many errors lie that affect the final result. To obtain correct data, you must follow a certain sequence of actions. First, make sure that the tires have cooled down - measuring the pressure on “hot” wheels immediately after a long trip will show inflated values due to thermal expansion of the air.
Remove the protective cap from the nipple and press the pressure gauge head firmly against the valve. At this moment, you will hear a characteristic hissing sound of escaping air - this is normal, since air is being bleed from the pump line or hose, but the measurement process itself should occur after the hissing has stopped. Press the head of the device with a sharp movement to release air from the tire into the measuring chamber.
☑️ Algorithm for checking pressure
Record the readings of the arrow or digital display. If you are using a mechanical device, hold it level so that your gaze falls on the scale perpendicularly - this will eliminate the error from parallax. After measuring, be sure to check the tightness of the nipple by lightly pressing on its center; if you hear a hissing sound, it means the spool needs to be replaced or tightened.
⚠️ Attention: When using rack and pinion pressure gauges, remember that after each measurement the rack remains in the extended position. Don't forget to reset the readings (press the bar back) before the next use, otherwise you will not measure the tire pressure, but the residual value in the device.
Measurement accuracy and instrument calibration
Any measuring instrument begins to “lie” over time, and a pressure gauge is no exception. Mechanical springs can fatigue and electronic sensors can drift. For an ordinary driver, the permissible error is about 0.1 Bar, but for sports tuning or commercial vehicles the requirements are much stricter. Regularly checking the accuracy of your meter is key to proper vehicle maintenance.
The easiest way to check pressure gauge at home - compare its readings with a reference device on a proven compressor or at a good gas station. If the difference in the readings of your home device and the stationary pump exceeds 0.2 Bar, it is better to replace the device or send it for adjustment. Digital models sometimes have a calibration function that allows you to correct factory settings.
Storage of the instrument also affects its accuracy. Do not leave the pressure gauge in the glove compartment with a heavy tool where it may be subject to vibration and shock. Mechanical pressure gauges do not like prolonged static loads, so do not leave them connected to a pressure source for long periods of time unless necessary.
The accuracy of the measurement directly depends on the condition of the wheel valve. A dirty or damaged spool may give false readings, so always keep the valves clean and replace the caps if they are damaged.
Common operating errors and their consequences
One of the most common mistakes is ignoring the temperature coefficient. As already mentioned, tire pressure changes depending on the ambient temperature and the heating of the rubber. A measurement taken immediately after arriving at the garage will show a value higher than the actual “cold” pressure. If you deflate the air to normal according to “hot” readings, then in the morning, when it’s cold, the tires will be underinflated.
Another mistake is using damaged or dirty pressure gauge attachments. Dust and small stones that get inside the measuring channel can jam the mechanism or break the tightness of the connection with the nipple. This leads to air leakage at the time of measurement and, as a result, to incorrect data. Regularly blow out the inlet of the device with compressed air.
You should also not save on buying a quality tool. Cheap pressure gauges from 1001-piece sets often have an error of up to 0.5 Bar or more, making them useless for precise adjustments. Better buy one good one digital or a high-quality pointer device from a well-known brand than guessing with the readings of an unreliable toy.
- 🌡️ Ignoring temperature - measurements only at “cold” temperatures guarantee accuracy.
- 🧹 Dirt in the channel - the cleanliness of the measuring channel is critical for the durability of the mechanism.
- 💸 Saving on tools - cheap instruments often have unacceptable scale errors.
How often should you check your tire pressure?
The optimal frequency of checking is once every two weeks or before each long trip. Rubber has the property of natural diffusion, losing up to 0.1 Bar per month even without visible damage. In winter, it is worth checking more frequently, since temperature changes significantly affect the volume of air inside the tire.
Can a tire pressure gauge be used for other purposes?
Theoretically, it is possible to measure pressure in any pneumatic systems with a similar range (for example, in a compressor receiver or inflatable boats), if the thread or adapter is suitable. However, it is not recommended to use a car pressure gauge for corrosive gases or liquids, as this may damage the internal seals.
Why do the pressure gauge readings on the pump and a separate device differ?
Standard pressure gauges on gas station compressors often have a large error due to intensive use and vibration. In addition, the length of the pump hose may make its own adjustments. Always trust the readings of your personal, proven device, and use the pump only to adjust the air volume.