RunFlat is a technology that makes it possible to ride on a punctured tire. There are models with a reinforcement in the form of a crescent, a support ring. Self-healing models are a novelty on the market.
From English Run Flat is translated "flat ride". If we adapt the term in relation to the automotive theme, then it implies driving on a flat tire. If ordinary rubber, if its integrity is violated under the weight of the car, immediately deteriorates, then RunFlat confidently adheres to the disk, allowing you to safely drive another 100 km.
This is a patented technology based on the principle of reinforcing the side edges. Thanks to this, the sides support the weight of the car. Due to the rigid cord, the car simply cannot settle. Today there is also a modernized technology that differs from the classics by the presence of polyurethane inserts around the rim. They make the structure even more rigid.
A regular tire has a court, a thicker bottom. The sides are weaker, they have a simple board for landing in place. With the new technology, the crescent-shaped inserts reinforce both the side and the bottom. Manufacturers keep the complete manufacturing technology secret.
Historical reference
The first vehicle to test the technology was the Mini 1275GT, released in 1974. Then other technologies were used for the manufacture of tires, not without special wheels and an ultra-low profile. The progenitor of the technology is considered to be Denovo, which released the Dunlop system.
Permanently inflated tires entered the wide market at the end of the 80s of the last century. People with disabilities pushed the idea to develop. A problem was raised in society: such citizens could not get to a car service with a broken wheel. And leaving the vehicle was problematic for them.
It was only in 1987 that Ranflet technology was used as part of the basic Porshe configuration. Today these wheels are available for almost all premium segment models. Some manufacturers come up with their own names:
- RFT,
- ZP,
- RunOnFlat,
- Flat Run and others.
If you decide to buy tires, you should know the labeling in advance.
Benefits
The most important benefit is increased safety. Even with a sharp decrease in tire pressure, the shape remains, the car does not move sharply to the side at high speed. This makes it possible to slowly reduce the speed without creating an emergency on the road.
Many are interested in how much you can drive. Usually the distance is 50-100 km (depending on the manufacturer) without damaging the tire. This distance is usually enough to drive to the nearest tire shop, even in a not very busy area.
Special Wound Flat tires reduce the chance of side cuts. This is true if the vehicle is used for off-road driving, where there is a high likelihood of defects due to sharp stones.
Another advantage is the possibility of choosing a tire not only with reinforced sidewalls, but also with a support ring system. It is located around the circumference of the disc, narrows the inside of the rim and prevents the rubber from deforming. With such a system, you can drive up to 320 km.
disadvantages
For many car enthusiasts, a significant disadvantage is the high cost. With the same parameters, tires made using a similar technology will cost an average of 20% more than conventional tires. Car enthusiasts say that it makes no sense to purchase such elements for the winter season, when driving involves low speeds.
The disadvantages include the complexity of the repair. Today, not all tire shops are ready to tackle RunFlat. Without the help of specialists, it will not be possible to remove and install the tire. Especially often, problems arise when repairs are needed in places remote from the city.
Drivers also note the peculiarities in depreciation. Since rubber has increased rigidity:
- an uneven surface is felt better;
- the chassis receives more hits;
- the life of the shock absorbers decreases faster.
If you read the reviews, you can find out that similar products weigh more than standard ones. This has a bad effect not only on dynamics, but also on fuel consumption. Experts recommend using run flat only in cars equipped with tire pressure monitoring and stabilization systems. They will monitor the integrity of the vehicle's tires. The stabilization system will allow you to control the car when a hole appears. The pressure monitoring system can show how large the puncture is, which tire is damaged.
Some features
If the car continues to move after the tire has been deflated, then it is better to replace it with a new one. Repair is possible only if a trace of a small puncture is found, when the rubber is not deflated. However, after the patch is installed, the strength of the product decreases. Tires marked V / W / Y cannot be repaired in any way.
After a puncture, the maximum permissible speed is 80 km / h, and the recommended speed is 50 km / h. Therefore, you need to be prepared for the fact that you will not be able to quickly get to the nearest service.
In the basic configuration, similar tires are installed on cars:
- BMW,
- Mercedes-Benz,
- Dodge,
- Cadillac.
Various options from manufacturers
Famous manufacturers:
- Michelin,
- Nokian,
- Continental,
- Pirelli,
- Kumho and some others.
Despite the identical technology, the tires from the manufacturers are different. The main differences are:
- the presence or absence of the possibility of eliminating the problem;
- the use of heat-resistant rubber as a raw material;
- introduction of polyurethane inserts.
Each factory outside only produces rubber with its own designation, but also produces models for various conditions: the ZP assumes that with such a wheel it is possible to move at speeds up to 80 km / h for 80 km. ZP SR is a marking, thanks to which it is clear that after a tire damage it is possible to move at a speed of 32 km / h. You can cover the same distance.
PAX assumes the presence of specialized discs inside which there is a supporting rim. The latter is mounted on almost all modern armored vehicles. Today you can buy self-medicating options. They don't have side boosters or support rings. There is an additional layer of sealant inside under the tread area. It quickly tightens the hole, leaving a pressure loss.
Thus, the new tires make it possible not to take the spare wheel on long trips, which significantly increases the free space in the trunk. There is also no need to independently replace the rubber with a new one. However, such models are not suitable for all cars; they can only be driven a relatively short distance at a minimum speed.
