How do runflat tires work?
RunFlat technology is based on the concept of reinforced tire sidewalls. When a regular tire deflates, it simply sag under the weight of the car, the beads move away from the rim and the sidewalls flatten onto the road. The weight completely destroys the tire within a few kilometers. The reinforced sidewalls of runflat tires hold the tire on the rim and successfully support the weight of the car after a puncture and complete loss of pressure. Moreover, all dynamic vehicle safety systems, such as ABS, ESP, DSC, CBC, etc. remain active.
The essence of the technique
So, what is runflat tires?
The design feature of the technological solution is that the side planes of the tire are reinforced.
A puncture of a standard tire leads to the fact that it very quickly loses pressure, deflates, and after just a few kilometers the vehicle begins to drive on a bare rim. Driving like this is unsafe; you need to stop and replace the damaged wheel.
Strengthening the sides allows the wheel to better support the weight of the car body. The power reserve increases many times over, that is, you can safely and comfortably get to a garage or service center to change a wheel in the most comfortable conditions, to install not a simple “banana”, but a normal tire.
There are no special restrictions on the operation of a punctured wheel made using the Runflat method. But a couple of rules should be followed:
- The maximum speed is 80 kilometers per hour. Exceeding it poses a serious danger; the rigidity of the structure may not be enough, which will provoke a rupture and loss of control.
- Power reserve – no more than 100 kilometers. However, this is more than enough even when driving on a country road.
It should be noted that the less the car has driven after a puncture, the higher the chance of a complete tire repair. This is an important economic point, since this tire costs significantly more than its standard counterpart.
Watch an interesting video about run flat tires:
Are there any disadvantages?
The main advantage of Run Flat is quite clear, but such tires have certain features that can be classified as negative aspects. The first point we have already noted is the high cost, so buying a whole set will cost a pretty penny.
Other points are as follows:
- Some drivers note a decrease in comfort during the trip; driving through obstacles is felt more acutely. This is due to the design features of the wheel; a rigid cord absorbs shock and vibration loads worse.
- A low depreciation coefficient increases the load on the suspension and, as a result, reduces its service life.
- The increased weight of tires leads to an increase in fuel consumption and a decrease in the dynamic characteristics of the vehicle.
- Installation of the tire is possible only in a specialized service, as it requires the use of special installation equipment. Russian realities are such that not every workshop has such equipment.
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Experts also advise installing such tires only on cars equipped with electronic pressure monitoring systems. The fact is that with a minor puncture, the car’s behavior on the road may not change at all, so the driver will not even know about it, but the fact of damage will sooner or later play a role.
The pressure monitoring system will immediately detect a malfunction, and the sooner appropriate actions are taken, the better. For both the driver and the car.
Watch a video review of Goodyear runflat tires (RunOnFlat) on the Lexus is250:
Marking
The designation on a runflat tire does not always appear in exactly this wording. Each manufacturer adheres to its own abbreviations and terms, which makes selection difficult.
Let's look at the most reputable brands and the labels they adhere to:
- Pirelli – RFT (RunFlat Technology) . The Italian manufacturer offers a wide range of products from 15 to 20 inches. This brand pleases with the variety of not only the size range, but also the types of tires. Models are presented not only for ordinary “civilian” cars, aimed at daily city use, but also special versions of tires for sports cars and SUVs.
- Nokian – RF (FlatRun or RunFlat) . One of the best tires for winter use, there are even options with studs. Tests have shown that the characteristics are maintained sufficient for a safe trip, even when traveling 150 kilometers after a puncture.
- Continental – SSR (Self-Supporting RunFlat) . High-quality products, positive reviews, varied product range.
- Dunlop-ROF . The main advantage is that these tires are suitable for installation on any standard wheels.
- Yokohama – ZPS (Zero Press System) . Japanese engineers continue to delight the world community with the release of technologically advanced products. These tires are no exception. A special type of rubber in the side planes of the tire, a wire made of a special alloy - all this prevents the rim from coming off even with serious damage.
- Kumho – XPR (eXtended RunFlat Performance) . These Run Flat wheels can be recommended to drivers who prefer “green” technologies. What does it mean? The cord in these tires is made from a revolutionary woven material that is recyclable and recyclable.
Please note that when installing tires of this type on a vehicle, they must all belong to the same brand. This is a safety requirement. Manufacturers use different rubber compounds and tread types, which can lead to differences in grip, skidding and other dangerous phenomena.
Run Flat tires are more expensive than their standard counterparts and require a slight increase in the load on the suspension. However, their use is a rational and correct step.
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Puncture protection is not only the ability to continue safe movement after damage, but also the exclusion of an explosion under severe external influence. For drivers who put safety first, the choice is obvious.
Additional photos
Eventually
The idea itself, embodied in run-flat tires, is, of course, good and correct. Everything that improves road safety must be implemented and improved. But, today, such tires have serious drawbacks, and in addition, for their normal and widespread use, an appropriate and, again, widespread, supporting infrastructure is needed. Without all this, such tires, although safe, remain quite rare on our roads. Let's hope that the situation with runflat tires will improve in the future.
Sources
- https://BlackTyres.ru/informaciya/informatsija-o-shinah/tehnologija-runflat/
- https://AtfService.su/opyt/ran-flet.html
- https://TechAutoPort.ru/hodovaya-chast/kolesnye-diski-i-shiny/runflat.html
- https://elektro-mobili.ru/tehnologiya-runflat/
- https://avtomobilprost.ru/runflat-chto-eto-shiny-s-tehnologiey-ranflet.html
- https://quto.ru/journal/autorambler/tehnologiya-shiny-runflat-chto-eto-takoe.htm
- https://AvtoNov.com/%D1%82%D0%B5%D1%85%D0%BD%D0%BE%D0%BB%D0%BE%D0%B3%D0%B8%D1%8F-runflat -%D1%87%D1%82%D0%BE-%D1%8D%D1%82%D0%BE-%D1%82%D0%B0%D0%BA%D0%BE%D0%B5/
- https://kolesospec.ru/baza/run-flat.html
- https://tires1.ru/shiny-run-flat/
Ran Flat rubber, features and disadvantages
Despite the previously noted advantages that allow you to move further on a broken wheel, run flat tires require careful handling. The fact is that its use is associated with a number of disadvantages.
- You can drive on a flat tire for a short time - no more than fifty kilometers, and not exceeding eighty km/h. Within the city limits, this is just enough to get to the nearest tire shop.
- However, even if you get there, they may not necessarily be able to help you. Especially if it happens somewhere in the outback or on the highway. Due to their design, run flat tires require special equipment; there must be a “third hand” (special device) at the tire changing stand. But this is not available everywhere.
- Such tires cannot be used on all cars, but preferably only on those equipped with directional stability systems and wheel pressure control. In this case, the disadvantages are a consequence of the advantages. If a tire punctures, it can sometimes be quite difficult to detect it without monitoring equipment. After all, according to external sensations, the movement on it will be almost the same as on a regular one. The easiest way to do this is to control pressure. And if a punctured tire is not detected in a timely manner, then in an extreme situation it can lead to unpredictable consequences.
- Increased vibration and deterioration in handling on bad roads are also inherent in such tires. They are best used on vehicles equipped with a suspension that can adapt to such driving conditions.
- Run flat tires are virtually irreparable. They are based on cord, and it is always deformed if movement occurs with reduced pressure in the wheels. These tires can be considered disposable, like airbags.
- Increased tire weight. And this causes an increase in unsprung mass, a deterioration in handling and dynamic characteristics.
- Increased price.
So do car enthusiasts need run flat technology or not?
Despite all the existing comments and shortcomings, such wheels are used more and more often by automakers. The fact is that this allows them to increase the usable volume of the car’s trunk by getting rid of the spare tire. In addition, safety is increased, and the consumer characteristics of the car are improved, due to the possibility of driving on a flat tire and eliminating the need to replace it on your own.
This is especially true for premium cars, for which price is not a determining factor.
Tires manufactured as run flats are increasingly becoming part of the everyday use of car enthusiasts. And although they are characterized by a large list of disadvantages, nevertheless, sometimes the ability to continue driving on a punctured wheel exceeds all the inconveniences. But this is everyone’s personal choice.
