What Tire Pressure is Too Low – How Low Is Unsafe to Drive

Robert Herrera-COR-Wheels

By Robert Herrera

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At this point, you probably have already heard far too many low-pressure tire accidents from radios and TVs; so yeah, we all know that underinflated tires are dangerous. The important question is what is considered low tire pressure. In which PSI range can we safely travel without worrying about road mishaps?

How Low Is Too Low Tire Pressure?

Most experts concur that tire pressure level between 32 and 35 PSI (PSI is short for Pound per Square Inch) is a MUST for every vehicle model. 

If you fail to have the tires inflated on time, the lowest tire pressure you can drive on is 20 PSI (but again, never let yourself fall to that point!). Any number below 20 is regarded as flat tires. 

Since most vehicles have incorporated the tire pressure monitor system (a compulsory feature in many regions), there’s no need to bend your head down to inspect its inflation every day. The sensors will send off alarms whenever significant drops are detected!

Long story short: 

  • 32 to 35 PSI: Compulsory
  • 20 to 28 PSI: Acceptable minimum
  • Below 20 PSI low: Refill your tire immediately 

What Factors Affect Your Tire Pressure? 

Besides alien objects that create holes in the tires, the most popular factors affecting tire pressure are air temperature and slow leaks. 

1. Slow Leaks

Locate A Tire Leak by soap

At first glance, they seem pretty similar to tire holes. However, unlike common punctures that result in flat tires at a startlingly fast speed, slow leaks are often drawn out. 

So where do they come from? A list of potential culprits includes: 

  • Improper seals between the tire and the wheel on new tire installation
  • Cracking tires
  • Damaged wheels
  • Broken air valves
  • Previous punctures with poor or undone repairs 

Thankfully, since the damage level is far more subdued than regular holes, tire replacements are not always necessary. Simple patches/ plugs sometimes will do, especially if you can detect the leaks early. 

2. Air Pressure

Why Does Pressure Change

Another common element is air temperature. In short: the tire expands in warm air and contracts in cool air. That’s why many drivers often find their TPMS systems displaying low-air signals in cold mornings – even when the car has not been in operation for weeks! 

As a result, most mechanics and manufacturers recommend tire inflation in chilly or cool weather, particularly if you have let the car sit idle for too long. 

What Are Some Common Signs of Too-Low Tire Pressure? 

1. Worn-Out Tires

Worn tires are among the first and most critical symptoms to keep an eye on if you think your car suffers from low pressure. 

Since the inflation is too low, the amount of rubber contact against the road will increase. It leads to a dramatic surge in temperature and faster wear than average.

Your failure to detect these wears on time may cause overheating problems. Don’t let us even start on all the catastrophes that might follow: the treads will separate, your steering will get totally broken, and driving malfunctions are only a matter of time. 

2. Worsened Gas Mileage

Look out for the deteriorated gas mileage, too. Most people do not often associate gas drops with low pressure, often assuming some technical issues are happening inside the car. However, these two issues are more related than one might think.

More specifically, once the tire pressure drops low, the car must use much more energy to move from one position to another (ex: when you stop the vehicle during traffic and get it moving again). This extra power waste causes the gas mileage to reduce significantly.  

3. Transparent Emission Increase

As previously mentioned, underinflation forces the car to work much harder than usual to get your vehicle to operate and perform properly. 

Not only is the gas mileage affected, but the emission levels also climb due to excessive stress on the engine. According to some recent studies, they will expel extra 21 pounds of CO2 into the air, polluting the environment. 

You might say, “Who cares about the environment?” But hey, don’t forget that certain locations have specific legal requirements about car emissions. Fix your tires right away, or your car might fail the emission tests!

4. Flapping Noises During Driving

Flapping, dull noise during the car’s operation is likely to be associated with underinflation. As we already stressed above, more rubber will contact the ground due to low pressure, causing the tire to slap incessantly on the road. That’s where the noises come from! 

These signals are much more serious than those introduced above, as they indicate the dangerous risks of flat tires below 20 PSI. Putting off the issue is not a choice; go to a gas station and fill your tires now! 

Is Low Pressure Dangerous? What Might Happen?

How low can a tire be before it is unsafe? As we already said, things are still within safe territories if the PSI falls between 20 to 28 PSI. Anything lower than that, and you have enrolled yourself on a roller-coaster trip! 

Some terrifying threats you have to brace yourself for in that case: 

  • Bad Fuel Economy: This issue is only expected. Your car requires much more power to drag itself across the street, after all! Experiments have concluded that every 5 PSI of underinflation equates to 2% fuel loss. 
  • Uneven and Premature Wear: Extra road and tire contacts cause poor traction and worn tread, requiring on-time repairs, maintenance, or even replacements. 
  • Compromised Car Control: The sidewalls of under-inflated tires will flex much more than usual – particularly during your steering/ cornering/ braking attempts. 

As the braking distance increases, your car will suffer from slower response rates – a huge disadvantage in emergency situations. One second of lackluster reactions can put anyone on the brink of life and death! 

  • Complete Tire Blowouts: Here comes the scariest consequence of all. It can happen anytime and anywhere without warnings, completely stripping you of your car control. Accidents are almost inevitable at this point. 

How to Avoid Low-Pressure Disasters

Low Tire Pressure

Cars that install Tire Pressure Monitor Systems can be quite convenient in these cases, as they will send warning messages in advance through the sensors. But what if your vehicle doesn’t have them? 

Then your best bet is to use tire gauges to check on the tire at least once a month. Put the device against the valve system, check its readings, and compare that number to the manufacturer’s recommended PSI

And if the results DO indicate low pressure, inflate the tires immediately. Do not tell yourself, “I will do it later,” because guess what? 99% of people who said so often forgot their tasks completely!

How Long Can Low-Pressure Tires Last On The Road?

Drivers can keep traveling for about 100 miles, though this number is just an estimation: who knows what other issues or obstacles you may encounter on the road? 

Let’s say you hit a nail on the highway right after the pressure drop; in that case, even 1 mile can be difficult for your car, let alone 100! 

Is Too-High Pressure As Dangerous As Too-Low?

Under-inflation

Yes; both overinflation and underinflation problems can be the death of your car, resulting in severe control malfunctions.

The maximum acceptable overinflating rate is 10% of the manufacturer’s required level. Go beyond that, and your driving experience will suffer.

FAQs

Is 25 PSI Too Low?

Yes, but still within an acceptable range. The lowest of the low should be 20 PSI. 

Is 50 PSI Too High?

50 PSI is normal for passenger cars or large 4WD vehicles, but probably too much for regular vehicles.

Conclusion

How low is dangerous tire pressure? This article has successfully addressed this question. The main takeaway of the day: always keep the PSI between 32 and 35, check your tire frequently, and never let it stoop below 20! 


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Robert Herrera

President & Automotive Expert at COR Wheels

Robert Herrera has been with COR Wheels for 17 years and has a great passion for the automotive industry. During his time at COR Wheels, he has driven and test-driven a variety of vehicles.


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