Though they first appeared in the mid-1980s, run flat tires (RFT) are now more popular than ever. With some auto manufacturers making them standard in new vehicles, more consumers are asking about run flats, their advantages, and how using them impacts driving.
Run flat tires are tires on which you can continue driving after a puncture so you can take time get to an auto shop or find a safe, level area to change your tire.
You can’t drive on them indefinitely, though. Check the manufacturer’s specifications to find out how fast and how far you can drive on your run flat tires. Bridgestone run-flat tires will allow continued operation even after a loss of some or all inflation pressure for up to 50 miles (80 km) at a maximum speed up to 50 mph (80 km/h.)
There are two primary types of run flat tire systems: the self-supporting system and the support ring system.
In most self-supporting run flat tire systems, the tire features reinforced sidewall construction that will continue supporting the vehicle in the event of air loss. This construction allows continued operation after the loss of air pressure up to the speed and distance specified by the manufacturer.
Support ring run flat tire systems, on the other hand, employ a ring of hard rubber or another structure that can support the vehicle’s weight in an air loss condition.
Since they continue performing even though they’re “flat,” all run flat tires, regardless of the specific system type, may only be used on a vehicle equipped with a Tire Pressure Monitoring System (TPMS). The TPMS alerts you as soon as one of your tires loses pressure. Without it, you might not know you were driving on an underinflated tire.
You don’t have to change your tire in dangerous or uncomfortable conditions. This is perhaps the biggest benefit of run flat tires and is the one of the reasons why they were designed.
With conventional tires, you have to replace a flat on the spot or have your car towed.
In a puncture situation, run flats are more stable than conventional tires. Since they’re made to support your vehicle even when they contain no air, run flat tires will help you maintain better control in a complete air loss situation than conventional tires.
As consumers continue rating safety high on the list of features they look for in a vehicle, the popularity of run flat tires is expected to grow. Since run flat tires work reliably with interconnected technologies like TPMS, it may only be a matter of time before they become the norm rather than the exception in new vehicles.
There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.
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There’s never a good time for a flat.
That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.
A flat tire is never a welcome occurrence and often appears at the worst place or time. You may think your only options are to wait for roadside assistance or struggle through putting the spare on. However, struggling through a dirty tire change, discovering you have no spare tire, or waiting prolonged periods for aid can be extremely frustrating.
Fortunately, with some forethought, you have another option. Run-flat tires have been around since the 1930s and allow you to continue driving, even when the tire goes flat. In theory, they enable you to drive far enough to make it to a service station. The question is: just how long can you drive on a run flat tire?
How long can you drive on a run flat tire? You can actually drive a fair distance.
Most run-flat tires can make it 100 miles, but there are limits on how fast you can drive on one. Consult the owner’s manual for exact specifications on how fast and far you can make it.
These are tires made with a reinforced sidewall capable of supporting a vehicle’s weight even if the tire has a total loss of air pressure. This means you can get a flat tire but still continue driving, just not for much longer. This also means you do not have to stop on a busy highway, in inclement weather, or in other unsavory conditions to fix a flat.
Here are some other features and must-knows for these type of tires:
If your tire goes flat, you will have to reduce speed to 50 miles per hour in order to maximize the distance you can cover. To know the exact limits for your vehicle and tires, check your owner’s manual.
A blowout on the road can be terrifying and result in destabilization as the car reacts to the sudden change.
With run-flat tires, you can expect to drive with better stability. Since it is designed to support the vehicle’s weight for miles without air, the sudden deflation will cause less tread destabilization and weight transfer as the car adjusts. You can expect handling and steering to remain rather stable from blowout to repair.
Another feature of this type of tire is the lower vehicle weight. You will not carry tire repair tools or a spare wheel, so overall weight is reduced. However, the added sidewall reinforcement of run-flats means that the weight may not decrease as much as you expect.
There are two types of run-flat systems: support ring and self-supporting systems.
The support ring has a ring of hard rubber or another firm structure to support the vehicle’s weight if air loss occurs.
The self-supporting system has reinforced sidewall construction to continue supporting the vehicle in the case of a flat. It permits continued operation without sufficient air pressure for the specified distance and speed provided by the manufacturer.
An important note is that both types of systems require a Tire Pressure Monitoring System (TPMS) that is typically equipped in the vehicle. The TPMS is required to monitor air pressure and alert you of lost pressure. Without the system, you may not know if you are driving on an under inflated or flat tire. The good news is that every vehicle manufactured since 2008 has some sort of TPMS built-in thanks to the TREAD Act.
These days, run-flat tires are standard on roughly 14% of new vehicles. To find out if your car is equipped with this type of tire, consult the owner’s manual or the car dealer where you procured the vehicle.
There are two things to know if a run-flat tire goes flat: 1) slow down and 2) stop soon. You can theoretically make it up to 100 miles on a flat run-flat, but you certainly do not want to tempt fate. Instead, use that extra time to put air in car tires or get to the nearest service station for professional assistance.
Be sure to keep the speed at around 50 mph or less as increased speed will increase the chances of injury.
Consider checking: How To Pump Tires At Gas Station
When it comes to how long you can drive on a run flat tire, the answer is far enough to get you to safety. The typical answer is 100 miles if you follow the 50 miles per hour rule of thumb. Generally, you will only want to drive long enough to get to the aid you require.
Did you find our guide interesting? Then feel free to check out:
How To Fix A Flat Tire
How Far Can I Drive With A Flat Tire
How Long Can You Drive On A Run Flat Tire
How To Tell If Tires Are Run Flat
How To Put Air In Dually Tires
How To Use An Air Compressor To Fill A Tire
Oleg Rastegaev
Photo: Dmitry Pitersky
Expert group: Andrey Mokhov | Oleg Rastegaev | Yaroslav Tsyplenkov
How bad is the comfort of Run Flat tires with reinforced sidewalls, on which, after a puncture, you can reach the tire shop? Why are they used today not only by BMW and Mini, but also by Mercedes-Benz, Infiniti, Lexus? We took a Bavarian "three-ruble note" with two sets of tires, "safe" and regular, and went to the landfill.
Struggling with punctures in pneumatic tires, already at the beginning of the 20th century, tire manufacturers tried to use porous rubber and bandage rings - but these unpractical solutions took root only in motorsport and in military equipment. It was not until 1973 that Dunlop offered to reinforce the sidewalls with an additional layer of rubber, which, in the event of a puncture, acted as a cushion between the rim and the road and allowed the movement to continue even at zero pressure. The technology was called Dunlop Denovo, reinforced tires were installed as an option for Fiat Panda, Rover P6B cars. Later, the name Run Flat was assigned to these tires - driving on a flat tire, that is, on a deflated tire. And they began to be truly mass-produced only at the end of the nineties of the last century, when the technology was adopted by BMW: Bavarian cars began to be designed without niches for a spare tire at all.
Run Flat tires are not only an additional layer of rubber on the inside of the sidewall, but also a different design of the carcass, bead ring and bead cord adjacent to it spare-document.
Moreover, it will not just be thrown into the trunk, but placed in a specially equipped niche under the raised floor, which, unfortunately, will significantly reduce the usable volume of the cargo compartment. So is it worth sacrificing the trunk for the sake of driving comfort? And by the way, how safe are run flat tires to drive when flat? I remember very well how, 14 years ago, at the Paul Ricard track, journalists sorted out a flat Pirelli Run Flat tire on a “one” BMW.
Pirelli uses the “Run Flat” label, while other manufacturers use more sophisticated abbreviations: RSC (Michelin), RFT (Bridgestone) or SSR (Continental)
Take me, too, Pirelli - a modern model of the Cinturato P7 in dimension 225 /55 R17. Two sets. The one that Run Flat, with reinforced sidewalls, is also marked with asterisks: the tires are homologated for BMW and Mini cars. And the function of the aggregate carrier will be performed by the BMW 320d. His native tires are slightly lower, dimensions 225/50 R17, but may the tire gods forgive us for a five percent difference in profile height.
Due to the stiffer sidewalls and developed humps, it is more difficult to mount Run Flat tires. Beading Run Flat tires is, of course, more difficult: not only is the sidewall much stiffer, but also the humps are higher (these are the tides that prevent the tire bead from sliding into the inner rim stream). The wheel designed for regular tires has a hump height of 5 mm, while the one designed for Run Flat tires has a hump height of 6.2 mm. But even our ten-year-old tire changer coped with the task.
The wheel of the Krasnoyarsk company K&K (left) with dimensions 7.5x17 h3 is designed for a conventional tire. And the one on the right is marked 7.5x17 Eh3 + - the abbreviation Eh3 + means Extended Hump, extended humps of increased height (shown by arrows) for Run Flat tires
Let's go!
Is there a difference on the go? At the same pressure of 2.2 bar, Run Flat tires give more vibrations on a relatively flat surface - the body trembles more noticeably in a short wave.
But on large bumps there is no significant difference: on both tires, the BMW 320d rides through the pits harshly.
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Tire puncture is a common problem that often occurs on Russian roads. For many drivers, its solution is not very difficult: it is enough to install a spare tire and drive to the nearest workshop. However, there are situations when it is quite problematic to do this. For example, not every girl is capable of installing a car spare tire. In addition, two tires are often damaged at once. It was to solve such situations that the RunFlat technology was created. It allows you to continue driving even if the tire is flat or there is a loss of pressure due to a puncture.
Like any development, RunFlat has its own features, advantages and disadvantages. You will learn about all the important nuances of technology from this article.
Translated into Russian, Run-Flat literally means "flat ride". This technology allows you to go further even in the event of a rubber puncture. RunFlat tires differ from conventional tires in the following details.
Wide side ring with additional reinforcement.
Rubber resistant to high temperatures.
Sturdy sidewall.
The presence of amplifiers in the frame.
Thanks to these features, run-flat tires do not sag under the weight of the car in the event of a tread puncture, as conventional tires do. Reinforced sidewall and other elements of RunFlat do not allow the rubber to come off the disk, keep the car in a straight line.
Depending on the design features, there are several types of RunFlat safety tires that do not descend from punctures.
They are sometimes referred to as zero pressure rubber. Tires with the RunFlat system have a reinforced sidewall and carcass. In addition, tires have a heat-resistant compound and special longitudinal ribs. All this ensures better cooling while driving. If the runflat carrier tire has been damaged, it will be able to stay on the rim and provide traction. The disadvantage of these tires is that they can only be installed on vehicles equipped with pressure control systems (RDC, TPMS, RPA) and directional stability (ESP).
Some manufacturers create a special layer inside the rubber that can tighten small punctures. Even if a sharp object flies out of the tire, the hole will be closed and you can go further without losing control. This is the key feature of self-sealing run-flat tires.
These tires are slightly different from regular tires. An elastic ring is installed on the wheel rim. It provides a supportive effect when pressure is lost inside a damaged run-flat tyre.
Tires with run-flat pressure technology won't eliminate the need to visit a tire shop. However, it is thanks to them that you can refuse the services of a tow truck and not carry a “spare tire” with you.
In the event of a puncture, tires with the RunFlat system will not be allowed to drive many kilometers (up to 80 km on average). At the same time, it is worth refusing to make sudden maneuvers and limit the speed to 80 km / h. It is because of the presence of such conditions that the use of RunFlat tires on vehicles without a system that controls the pressure level is prohibited. The driver may not notice the damage and continue to drive aggressively, which is extremely dangerous. In addition, it is worth remembering that each manufacturer sets its own speed limits and distances for traveling on damaged tires with the RunFlat system.
Run-Flat tires are sold individually or as a complete set. Which option to prefer is the personal choice of each driver. The supply of complete run-flat tires is a unique offer from Mercedes-Benz and BMW dealers.
Installing tires with RunFlat technology will not cause additional difficulties. Overboarding can be done every season. To carry out the work, you will need professional qualifications, Easymont (“Third Hand”) equipment, which makes it easy to remove tires with the RunFlat system. All this can be found in a quality tire shop. Some models also allow puncture repair.
The advantages of safe tires are obvious.
Safety.
Saving time for reordering.
Improved steering response.
Save space in the trunk by eliminating the spare wheel.
RunFlat technology also has some disadvantages.
Limited use (the car must have a tire pressure monitoring system).
High price (unlike conventional tires, it is 15-25% more expensive).
Increased sidewall stiffness leads to reduced driving comfort.
Continental IceContact 2 SUV
The design of the tire from the German manufacturer has a rigid reinforced sidewall. Even in the event of a loss of pressure, it does not differ externally from a normal inflated tire. At the same time, RunFlat tires from the Continental brand have high levels of acoustic comfort. The tires respond quickly to the movement of the vehicle's steering wheel and provide driving safety through a directional pattern and the inclusion of steel studs.
Goodyear Eagle UG GW-3
Runflat tires from an American manufacturer, suitable for those who like to move at high speeds. Tires are not studded, but do well in wet snow porridge. At the same time, decent grip of the car with the road is noted during heavy braking, cornering at speeds up to 100 km / h. The run-flat design of tires provides acoustic comfort, the ability to continue moving even with a sudden loss of pressure.
Bridgestone Blizzak RFT
These tires from a Japanese manufacturer are available in diameters from R16 to R19.
Reinforced sidewalls of RunFlat tires help maintain directional stability even during pressure loss due to damage. The asymmetric pattern contributes to reliable grip on all types of surfaces and a high level of maneuverability. The RC-polymer modifier in the rubber compound ensures the stability of run-flat tires during temperature fluctuations.
Nokian Tires Hakkapeliitta 7 SUV
RunFlat technology is implemented in the design of tires from sizes R17-R19. The special rubber composition and reinforced sidewalls allow the car to travel up to 100 km even if the tires are deflated. The symmetrical pattern with the inclusion of metal studs provides reliable grip on icy and snowy roads.
Dunlop SP Sport Maxx TT
This UK manufacturer's RunFlat tire offers good traction and wear resistance. In order for the tires to remain stable even when pressure is lost, nanoparticles similar in properties to diamond are added to the rubber composition.
The sidewall is reinforced with Kevlar thread. Tires are not afraid of punctures, resistant to minor damage. While driving, the car is stable, precise in control, not subject to aquaplaning and skidding when cornering. All this is provided by the tread pattern, built using mathematical modeling, and the special design of the side blocks.
Kumho ECSTA PS71
These RunFlat tires are available in sizes R16 to R19. Suitable for those who like to ride at high speeds. Reinforced sidewall adds rigidity to the structure, which contributes to better maneuverability, good traction. The South Korean manufacturer also took care of maintaining an affordable price, which is successfully combined with a high level of quality and wear resistance.
Yokohama Advan Sport ZPS
Tires from the Japanese manufacturer are designed according to the principles of the RunFlat system, which ensures safety even when the pressure is released. They are available in sizes R16 to R20.
