Situations when it is necessary to artificially reduce tire pressure do not often arise for drivers, but they always require precision and accuracy. Most often this is due to preparing the SUV for driving on soft ground, sand or snow, where increase in contact patch critical for patency. Bleeding air may also be required during seasonal tire replacement for a tighter fit of the bead on the disc or during emergency repair of a puncture.
An incorrect procedure may result in damage. spool or even detachment of rubber from the cord if you overdo it with pressure. In this guide, we will look at three main methods of reducing pressure: using a specialized deflator cap, a standard tool cap, and improvised means. Each of them has its own nuances that must be taken into account.
Before you begin, make sure the vehicle is parked on a level, hard surface. It is critical to measure the initial pressure with a pressure gauge before starting the procedure, so that you know exactly how many atmospheres need to be removed and to what value the indicator should be brought. Improvisation in matters of tire pressure is unacceptable.
Why might you need to lower your blood pressure?
The main reason why car owners are looking for information on how to get a flat tire is off-road training. In sand, mud or deep snow, the standard factory pressure (usually 2.0–2.5 atm) makes the tire too hard. It cannot adhere to uneven terrain, which leads to slipping and digging of the car.
By reducing the pressure to 0.8–1.2 atm, we increase the area of contact of the tread with the surface. This works as a natural stabilization and traction system. However, it is important to understand that driving on “flat” tires on hard asphalt is prohibited: the sidewalls tires begin to overheat due to excessive bending, which leads to their destruction.
Another scenario is when the tire needs to be removed for repair or replacement. Sometimes, to make the bead come off the rim more easily, experienced professionals recommend reducing the pressure slightly to loosen the tension of the rubber. In rare cases, this is done to soften the ride when transporting particularly fragile cargo, although this violates the manufacturers’ recommendations.
⚠️ Attention: After driving off-road with reduced pressure, be sure to restore normal levels before heading out onto the highway. Ignoring this rule may result in the tire exploding at high speed.
Using a deflator cap
The most professional and safe way is to use a special deflator cap. This device replaces the standard cap and allows you to precisely regulate the flow of outgoing air. Such tools are often used by professional raiders and athletes.
The principle of operation is simple: you screw on the deflator instead of a regular cap. There is a spring-loaded valve inside it, which, when pressed on the center, opens the air from the chamber. The main advantage is the ability to set the target pressure: as soon as it reaches the desired value, the flow will automatically shut off.
The process looks like this:
- 🛠️ Unscrew the standard plastic cap and screw the deflator tightly onto the nipple.
- ⚙️ Using the adjusting screw (if the model allows) or simply pressing, set the desired pressure.
- 💨 Wait for a characteristic click or the sound of escaping air stops, which signals the completion of the process.
Usage deflator eliminates the human factor and the risk of flattening the tire too much. However, it is worth remembering that this is additional equipment that you need to carry with you and which has its own cost. For a one-time trip to the country, buying a set of four such caps may be redundant.
When screwing on the metal deflator, do not use excessive force to avoid stripping the threads on the brass nipple rod. Brass is a soft metal.
Method using a regular cap
If you don’t have a special tool at hand, you can use the back of the standard cap. On the inside of most plastic and metal caps there is a ridged protrusion designed just for twisting. spool.
This method requires greater caution and constant monitoring. You need to unscrew the spool itself (the internal valve), and not just push it. This will open a wide channel for air to escape quickly. You need to act carefully so as not to lose a small part.
Algorithm of actions:
- 🔩 Carefully insert the protrusion of the cap into the nipple hole and hook the edge of the spool.
- 🔄 Slowly rotate the cap counterclockwise until the spool begins to come out.
- 🌬️ Control the pressure with a pressure gauge, as the air will come out very quickly.
The main risk of this method is the possibility of dropping the unscrewed spool into mud or sand. If this happens, the nipple will become leaky and it will be impossible to inflate the tire without replacing the valve. Therefore, carry out the procedure only in a clean place or with a cloth underneath.
☑️ Checking readiness for descent
Bleeding air by pressing the spool
The most common “old-fashioned” method, which does not require any tools, except, perhaps, a thin object (key, nail, screwdriver handle). The essence of the method is to mechanically press the central spool rod.
There is a spring-loaded valve inside the nipple. By pressing it, you open a hole for air to escape. The complexity of the method is that the air flow is very powerful and unregulated. It's hard to pinpoint exactly when to stop.
Safety precautions for this method:
- 👁️ Use a transparent ruler or simply watch the pressure gauge scale every 3-5 seconds.
- ✋ Do not use sharp objects that could damage the rubber seal inside the valve.
- ⏱️ Work with short presses, allowing the pressure to stabilize after each deflation.
The disadvantage is the unevenness of the result. While you are running from wheel to wheel with a pressure gauge, the pressure in one wheel has already dropped, but in the other it has not yet. In addition, when pressed for a long time, the metal shaft of the tool can cool down and freeze to the fingers in winter.
⚠️ Attention: Never leave a vehicle with flat tires unattended for long periods of time. The weight of the machine can cause the sidewalls to become irreversibly deformed.
Recommended pressure table for different conditions
Understanding to what level the air needs to be deflated comes with experience. However, there are general recommendations that should be followed to avoid damage. tire design. Below are average values for standard passenger cars and crossovers.
You need to start from them.
| Surface type | Recommended pressure (atm/Bar) | Reduction target | Maximum speed |
|---|---|---|---|
| Asphalt (standard) | 2.0 – 2.5 | Normal Operation | Up to 110 km/h |
| Soil/Gravel | 1.6 – 1.8 | Improved grip | Up to 60 km/h |
| Sand/Snow | 1.0 – 1.4 | Maximum contact patch | Up to 40 km/h |
| Deep mud | 0.8 – 1.2 | Self-cleaning tread | Up to 30 km/h |
As you can see from the table, the difference between normal driving and off-road preparation can be twofold. Sidewalls of modern low-profile tires Such experiments are less tolerated, so owners of sports cars should be especially careful.
Reducing the pressure below 0.8 atm on standard tires without reinforced sidewalls (RunFlat) can lead to wheel disassembly while driving.
Pressure restoration and safety measures
After overcoming a difficult section of the path, it is imperative to return the pressure to normal. You cannot drive hundreds of kilometers along the highway on “soft” wheels. To do this, you will need a car compressor or pump.
When pumping, it is important not to overheat the compressor. Let it cool down every 3-5 minutes of continuous operation. Also check the temperature of the tire itself: if it is hot, the pressure gauge readings will be higher than the real ones (air heating effect), so it is better to do the final check on cold wheels.
Post procedure checklist:
- ✅ Make sure all caps (standard or deflators) are screwed on tightly.
- ✅ Check the tightness of the nipple by spitting on it or applying soap foam (there should be no bubbles).
- ✅ Visually inspect the sides for hernias or swelling after exercise.
Regularly checking your blood pressure is the key to safety. Even if you don't plan any off-road adventures, it's worth checking your tires once a month. This will help save fuel and extend the service life chassis car.
What should I do if the spool releases air after pumping?
If you hear a hissing sound after pumping, dirt may have gotten into the threads or the rubber seal may be damaged. Try unscrewing the spool, wipe it and screw it back in. If the hissing remains, replace the spool; this is a consumable item that costs pennies.
Frequently asked questions (FAQ)
Is it possible to flatten a tire if there is no pressure gauge?
Highly not recommended. Without a pressure gauge, you are operating blindly. Too low a pressure will cause the wheel to break up when turning, and insufficient reduction will not give the effect of cross-country ability. As a last resort, use the “by eye” method, relying on the degree of compression of the tire by hand, but this is very inaccurate.
Is frequent pressure changes harmful to tires?
The change in pressure itself does not harm modern rubber if it is within acceptable limits. Driving at the wrong pressure (too low at speed or too high when off-road) causes harm. Sudden temperature changes inside the tire during inflation/deflation are also undesirable, but acceptable.
Do all tires need to be deflated equally?
Yes, to maintain directional stability and predictable behavior of the car, the pressure in all four wheels (or on the axle) must be the same. The difference can cause the vehicle to pull to the side and cause uneven tread wear.
What is the best tool to buy for an SUV?
The optimal choice would be a set of four mechanical deflators with a fixed pressure (for example, 1.0, 1.2, 1.5 atm). They are reliable, do not require batteries and allow you to quickly prepare the car for driving on the ground without running around with a pressure gauge.