What Are the Dangers of Running on Flat Tires?

As a car owner, you might know how hard it is to maintain tires. Flat tires are the most common problem with cars and can be caused by low pressure or something as simple as debris in the tire treads. The good news is that there are some easy ways to avoid flat tires and keep your car running smoothly! 

Keep your tires properly inflated to prevent them from running flat. If you are experiencing problems with your tires, you need to take care of the issue as soon as possible. 

This blog post will give you some tips on what to do if your tire goes flat and how to avoid blowing out another tire in the future. It also includes a list of things that can cause a tire to go flat so that you know what signs to look for. So keep reading if this sounds like something you want information about!

A run flat tire is a type of tire that can be driven on after it has lost pressure. To know more about how far can you drive on a run flat tire, check out here.

How Does Run-Flat Technology Work?

It is important to consider how a tyre loses air pressure and how the run-flat tyre manages to ensure safety and continuous driving. A tyre loses air either through penetration or a cut to the tread or sidewall area, usually causing loss of control of the vehicle or forcing the driver to stop and change the tyre.

Run-flat tyres work like conventional tyres. They still contain air; to reduce the load that the run-flat system has to bear, spread the weight of the vehicle evenly on the road surface, and maximize the contact patch between the car and the road. Once run-flat tyres detect the first signs of deflation (usually caused by punctures), it automatically applies several counter-effects to ensure safety and continuous driving.

A run-flat tyre offers a very high standard of driving comfort; the driver will barely notice any pressure loss in the tyre. For this reason, these tyres are used on vehicles equipped with a tyre pressure monitoring system, which will display the drop in tyre pressure on the dashboard instrument panel.

There are many different types of run-flat tyres from a variety of tyre manufacturers. We can, however, identify 3 basic technologies:

Self-Supporting

The tyre is built with stiffer sidewalls (sometimes 50% thicker) that can bear the vehicle’s weight even when the pressure within the tyre is greatly reduced. The sidewalls are typically constructed of layers of rubber and a heat-resistant cord that prevent the sidewalls from folding or creasing. The bead around the edge of the tyre is also specialized to grip the wheel rim to avoid becoming detached from the rim. In addition, the tyre’s sidewalls are usually made of an extra layer supported by a heat-resistant cord to keep the tyre in the original position even under the weight or road bumps.

Self-Sealing

These tyres contain an extra lining within the tyre that self-seals in the event of a small hole due to a nail or screw. In this way, the loss of air is prevented from the outset so that that the tyre is either permanently self-repairing or at least loses air very slowly. However, this type is usually less efficient as it still allows the air to get out of the tyre – until the seal comes into effect. Additionally, it could fail to stop the deflation completely, but still, it could allow the driver to reach the first service centre.

Auxiliary-Supported

In this system, there is an additional support ring attached to the wheel that can support the vehicle’s weight in the event of a loss of pressure. While these systems generally offer better ride quality because their sidewall’s stiffness can be equivalent to a standard tyre, the requirement to have both special wheels and special tyres increase cost and limit these systems from widespread use.

Self-Supporting Tire

The most common type of run-flat technology in use today is the self-supporting tire. The tire’s sidewalls are heavily reinforced to support the vehicle when the air pressure is low or even when the tire has lost all its pressure.

Pros:

You can drive on a flat tire: The primary benefit of a self-supporting tire is that it allows you to keep driving on a flat about 100 miles after all the air has gone. So you don’t have to get out of the car in the cold, or the rain, or onto a busy highway or on the street in a sketchy part of town. Drivers will usually have to reduce speed to about 50 mph to get the maximum range. The owner’s manual will have exact figures for each tire/vehicle application.

Better stability after a blowout: Because this tire can support the vehicle for miles without air, a sudden deflation results in less weight transfer and tread destabilization. Steering and handling will remain near normal.

Lower vehicle weight: Vehicle weight should theoretically go down with the spare wheel and tire repair tools eliminated. But it won’t be as much as you might expect since run-flats weigh more than regular tires due to the added sidewall reinforcement.

Cons:

No spare: Vehicles equipped with run-flats do not carry a spare wheel and tire, which means they don’t have a jack or tools either. Eliminating the spare tire and reallocating that space to some other purpose (styling, a third-row seat, interior room, etc.) is a big reason why carmakers offer run-flats.

Reduced tread wear: A 2013 study by J.D. Power found that people replaced their run-flat tires an average of 6,000 miles sooner than owners using conventional tires. Opinions differ on the reason, but one theory is that tiremakers put a soft tread compound on a run-flat tire to counter the hard ride. A side effect of the softer compound is shorter tread life. Actual data on the longevity of run-flat tires have been hard to find. But according to a 2018 J.D. Power owner survey, owners reported higher overall satisfaction with run-flat tires. In addition, they did not lag behind conventional tires in the survey.

Blowouts are still possible: If a driver fails to heed or notice the warnings and drives beyond the zero-pressure range or above the speed limitation, the tire can begin to disintegrate, with the same destabilizing effects. Additionally, if the puncture occurs on the sidewall or the tire hits a large object, the driver will have to call a tow truck. The J.D. Power study found that “customers with vehicles equipped with run-flat tires are nearly twice as likely as those with vehicles equipped with conventional tires to have to replace a tire due to a flat or blowout.”

Hard to tell if it is low on air: A side effect of the stiffer construction is that the sidewalls do not bulge if the air pressure is low. Therefore, it is critical to have a tire pressure monitoring system and check your tire pressure frequently. Otherwise, you’ll never know when you have a flat.

Harsher ride: The stiff sidewalls that make a run-flat work also result in a harsher ride. The automaker usually tunes the suspension to offset the rougher ride if the vehicle came with run-flat tires from the factory.

Cost: Run-flat tires are more expensive to replace. Prices will vary by tire type and purchase location, but it’s not uncommon to pay a $40-$65 premium for a run-flat-tire. Also, many run-flats cannot be repaired and often need to be replaced in pairs.

Less on-shelf availability: Because run-flats aren’t a big-selling tire, drivers shouldn’t expect to roll into just any tire shop and buy them. It may be easier to do so in larger cities, but if you’re a run-flat user on a road trip and get a flat near a small town, you’ll probably have to make a detour to find a suitable new tire. Or worse, you may have to stay overnight, waiting for the tire to be shipped.

Why You Really Shouldn’t Drive on a Flat Tire

Pull Over Immediately

We’ve all seen it before; some of you may have even done it. A vehicle has had a tire go flat, and the driver is slowly driving on the shoulder of the road. Instead of waiting on a tow truck or installing the spare tire, drivers sometimes try to ‘limp’ their cars to a nearby service centre. This is not the right response to a flat tire.

A Flat Doesn’t Always Mean a New Tire.

This all may sound a bit extreme, but it’s true. Let’s start with why driving on a flat tire is not a good idea for the tire itself. A lot of flats occur because the tire gets punctured. Most things that create the puncture are small, like nails and screws. As John Carpenter, field service manager for Toyo Tire Canada, states, “Industry guidelines allow repair of punctures of up to 1/4″ in diameter in a tire’s tread area.”

Not Just the Tire Is at Risk

And if a tire degrades enough when being driven while flat, it can start to break apart and cause damage to several important components on a car. Brake lines, rotors, callipers, suspension components, wheels and fenders can get serious damage from a flat tire that begins to flail around in the tire well. What starts as a simple $30 tire patch can end up costing thousands of dollars if a flat tire is driven on for an extended period.

Regularly inspect the tyres, paying attention to:

• Inflation pressure – Over and under-inflated tyres result in uneven tread wear and affect vehicle handling, cornering and braking. When overinflated, there is less contact area with the road, and the tyre is more prone to damage from road hazards like potholes. Under-inflated tyres increase fuel consumption and are prone to heating up, causing the tyre to fail prematurely and possibly causing a blowout, which can be dangerous at highway speeds. Check the pressure at least once a month when the tyres are cold.

• Tread depth – New tyres have a tread depth of 8 to 9mm. As the tyres are used, the tread will wear down. Any tyre with a tread depth of 1.6mm or less must be replaced. For easy indication, if the tread level is flush with the tread wear indicators in the grooves of the tyre tread, then the tyre must be replaced. Do not drive on a tyre where the steel belts are showing through the tread.

• Treadwear – Uneven tread wear is a sign that something is wrong. Overinflated tyres will wear the centre tread more than the outer edges, and the opposite will happen with underinflated tyres. If only one of the edges is worn, there are patches of wear, or one side of the vehicle shows greater wear. This is an indication that the wheels need to be balanced or aligned. Wheel balancing and alignment is important because, like tyre pressure, it affects steering, braking and fuel consumption. Bald spotting indicates worn shock absorbers or suspension. Front tyres wear quicker due to the engine’s load. Therefore consider tyre rotation after 10 000km.

• Defects – Check for any bulges, cuts or cracks, and if found, replace the tyre. Also, check for and remove anything that has become stuck in the tread. However, if something has gone through the rubber, such as a nail, and the tyre is still inflated, leave it in until you can get to a fuel station or tyre repair centre, as removing the item could cause the tyre to deflate.

• Age-Old tyres, regardless of tread depth, aren’t safe. It is recommended that tyres are replaced six years from the date of manufacture. You can determine the age of tyres by looking at the DOT code on the side of the tyre. The last four digits indicate the week and year that the tyre was manufactured. For example, a DOT code ending in 0514 indicates that the tyre was manufactured in the fifth week of 2014.

Advice for the Driver With Run Flat Tyres

Whether you are the vehicle owner or the driver of a vehicle with run-flat tyres, it would be worthwhile to consider a few safety aspects before going on the road.

  • When properly used, run-flat tyres meet the highest standards in terms of safety and handling characteristics. 
  • It is best to always check with the guidance provided by your vehicle manufacturer/tyre supplier on how to use these tyres.
  • Before you start your journey, make sure whether you have run-flat tyres or conventional tyres – confirm that it is a run-flat tyre by checking the sidewall for the mark of identification. 
  • Run-flat tyres should only be fitted on vehicles equipped with a tyre pressure monitoring system and preferably where the tyre was fitted as original equipment by the vehicle manufacturer.
  • Vehicle manufacturers recommend the fitment of approved wheel and tyre combinations, as non-approved wheels or tyres may contact the vehicle body due to impermissible tolerances, even though they are the same size. 
  • It is not recommended to change the fitted run-flat tyres to conventional ones because of a constructional difference that may influence handling and performance. 
  • In the case of an emergency, it is possible to fit a standard tyre to the car – if the vehicle has a spare tyre. This can only be a temporary solution for a limited time. The standard tyre must also comply with recommended speed and load recommendations from the vehicle manufacturer.
  • Vehicles fitted with run-flat tyres, in most cases, do not have a spare tyre. If you wish to change to conventional tyres, it is recommended that you consult with your local vehicle dealer to obtain written confirmation. The Dealer must also include which tread pattern and sizes to fit if a conventional tyre is allowed. 
  • Run-flat tyres can be repaired as with other tyres. If the hole is in the belt or crown area, a mushroom plug repair can be done for temporary emergency measures, but the tyre should be replaced at the earliest possible convenience. 
  • Repairs cannot be carried out in the shoulder or sidewall areas like with conventional tyres. 
  • Manufacturers, however, recommend run-flat tyres are replaced and not repaired, as it is difficult to know exactly what damage has been caused to the tyre once deflated. 
  • Special care is needed when mounting or de-mounting a tyre to a rim where a pressure sensor is used – rather, use professionals to change these tyres.

Safe tyres are very important safety components in every vehicle. They are important for steering and proper vehicle control and speedy and effective response in emergency and accident avoidance. However, we have the added danger of questionable road conditions off the main roads – and criminals preying on drivers and passengers in distress. If it is possible to avoid stopping next to the road to change tyres – this could only benefit the safety of drivers and passengers.

We can expect that run-flat tyres will increase in popularity and be an important addition to many newer vehicles on our roads!

Running Flat Tires FAQs

Should I Drive on a Flat Tire? 

No. Do not drive on a flat tire.

However, it may be necessary to travel a short distance on a flat tire when pulling over to the side of the road. But driving on a flat tire is a surefire way to put your passengers at risk and seriously damage your vehicle. If your vehicle is equipped with Bridgestone Run-Flat tires, you can typically drive 50 miles at up to 50mph on a punctured tire*.

Not only does driving on a flat tire dangerously decrease your vehicle’s handling, but it may also cause structural damage to the wheel, brakes, alignment, and potentially other components like your suspension and steering system. It may be tempting to “limp” your car to the nearest repair shop, but by driving on a flat, you’ll likely end up paying to repair much more than just the tire.

So if you’re not supposed to drive on a flat, what should you do instead? The first thing to do is safely maneuver to the side of the road to address the problem properly. From there, you’ve got a few options. 

First, you can either replace the flat with your spare tire or use an emergency sealant to fill any punctures. It’s worth noting, however, that emergency sealants typically only seal tires with punctures that are ¼ inch or smaller. Therefore, they will not help if your tire is shredded, blown out, or has a large puncture. 

Why Did My Tire Go Flat Overnight?

BAD ROAD CONDITIONS

The worse the condition of the road, the greater your risk of getting a flat tire. Uneven paving, potholes, and debris are enemies to your tires–sometimes causing an immediate problem and other times causing a slow leak.

HEAT

Not-so-fun fact: your tire is most likely to go flat during the hottest months of the year. High temperatures cause the air in your tires to expand, which in turn increases the tire’s internal pressure. When the pressure rises, so does your chance for a leak or total blowout. Most Tire Pressure Monitoring Systems (TPMS) measure your tires when they become underinflated–not overinflated–so don’t wait for your dashboard light to pop on like it tends to do on cold winter mornings.

VALVE STEM LEAK

A hole in the rubber doesn’t always cause flat tires. Instead, a malfunction or leak in the valve stem can be the culprit. The valve stem is the part of the tire that you unscrew when adding air. Any damage or dirt on this small piece could cause your tire to lose air until it’s completely flat.

NORMAL WEAR & TEAR

Sometimes there isn’t a major incident that causes a flat tire. Normal wear and tear can get the best of your tire! As you drive, the tread on your tires gradually wears down. This can make your tires more vulnerable to the typical hazards of daily driving–in other words, more likely to go flat!

When Should You Use a Tire Sealant?

In an Emergency

One of the most obvious times to use a tire sealant is during an emergency. For example, if you step out your front door one morning and discover a flat tire because of a slow leak, that’s not as pressing as developing a flat tire on the road. However, if you are on the road and suddenly have a flat, that’s when a can of sealant can be helpful. It’s an especially good solution if you only have a small puncture and need to patch it long enough to get to a mechanic for a tire replacement.

When You Can’t Safely Change a Tire

Flat tires can happen at any time, but if you experience one in an area where you can’t safely change the tire, the sealant may provide a good alternative.

When a Tow Isn’t Available

Picture this: You’re making a late-night trip and suddenly spring a flat tire. Unfortunately, you don’t have a spare available and are stuck on the side of the road in utter darkness. You try to call a tow truck, and it’s going to be literal hours before someone can get to you. So you can either camp in your car until it’s light out and the tow arrives, or you can opt to use your can of sealant.

When Time Is of the Essence

Changing a tire can sometimes take more time than patching a hole with sealant. So in some cases, you might be better off opting for that can of Fix-a-Flat, rather than trying to rush through swapping a flat for a spare. If you don’t have the time to throw on a spare, reach for that can of sealant to be on 

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