Q&A

How can we detect a loss of air pressure?
A tire pressure monitoring system alerts the driver to a loss of tire air pressure. It is necessary to equip the Run-Flat tire with such a system to ensure the driver does not continue driving unaware that a tire has been punctured.
What is the difference between Bridgestone's Run-Flat systems and those of other manufacturers?
Both of Bridgestone's Run-Flat systems - the sidewall-reinforced type and the support-ring type - can be equipped on conventional wheels, whereas the systems of other manufacturers require a special type of wheel.
Can Run-Flat tires and systems be equipped on any car?
Technically, it is possible to equip Run-Flat tires on any type of car. However, we recommend using them on cars specifically designed for Run-Flats, or at least, cars designed with that option in mind, as it is necessary to fit the tire pressure monitoring system.
Will Run-Flat tires be widely popularized in the future?
The popularity of the Bridgestone Run-Flat concept will depend largely on how automakers view the system. However, demand is expected to increase in the future as consumers become more aware of safety and environmental concerns.
    Sales results and forecast for Bridgestone Run-Flat tires are as follows:Sales Results and Forecast
  • 2002: 200,000 units
  • 2003: 500,000 units
  • 2004: 800,000 units
  • 2005: 1,800,000 units
  • 2006 (forecast): 2,400,000 units
Where can Run-Flat tires be fitted?
Run-Flat tires can be installed at most car dealers or tire shops throughout Japan. If the tire pressure monitoring system needs to be reset, it must be done by the car dealer. In Europe and the United States, Run-Flat tires can only be installed at tire shops staffed with trained technicians.
Are any studless Run-Flat tires?
Most sizes approved as original equipped Run-Flat tire are already available for studless tire as well at car dealers and tire shops. We plan to gradually increase the number of sizes going forward in accord with demand from customers and automakers.
Is it possible to repair a Run-Flat tire that has been punctured?
It depends on how far and at what speed the car was driven after the puncture was sustained. Repair is possible only if deemed so by the tire sales store.
Preconditions include a puncture of less than 6mm for both side-reinforced type and support-ring type Run-Flat tires, plus minimal damage to the support ring in case of the latter.
However, it is strongly recommended that the tire is replaced as its durability will have been weakened after being repaired.
How far can a car continue to drive safely on a Run-Flat tire after a puncture?
Please refer to the individual vehicle manual for the maximum speed and distance the car can be driven safely after a puncture as it is subject to certain conditions such as weight and structural design.
For example, BMW guarantees that the Z4 is able to be driven up to a distance of 160 kilometers at a speed of up to 80 kilometers per hour after a puncture.
Do Run-Flat tires compromise comfort?
As the quality of the rubber differs from conventional tires, handling may appear a little stiff at times. There is almost no difference in comfort relative to conventional tires in cars where Run-Flats are standard equipment, however, as they are specifically designed for that type of tire.
Does the greater weight of the Run-Flat tire impact driving performance or fuel economy?
Although Run-Flat tires may be 10~15% heavier than standard tires, eliminating the need for a spare tire reduces overall weight, and as a result, there is very little impact on either driving performance or fuel economy.
Which is better in quality, sidewall-reinforced Run-Flat systems or support-ring type Run-Flat systems?
The basic features are essentially the same. To cover most car types, Bridgestone applies support-ring type Run-Flat systems to larger SUVs and sedans including limousines, and installs sidewall-reinforced Run-Flat systems on other types of sedans and coupe sports cars.