Driving on Run-Flat Tires
Run-flat tires are designed to be able to continue driving after loss of air pressure for a limited speed and distance.
Most drivers have at one time or another encountered a flat tire; it is almost inevitable.You may even have had to install your spare tire on the side of a busy road, potentially having put yourself in harm’s way. Run-flat tires can help eliminate that risk.
Run-flat tires generally have two different construction types; self-supporting or a support ring sytem.
Self-Supporting Run-Flat Tire
The most common type is the self-supporting run–flat tire. This means that the sidewall construction is reinforced so that the tire can support the weight of the vehicle in case of air loss.
Support Ring System
The other type of run-flat construction is called a support ring system. This type of construction has a physical structure that is attached to the wheel, so that the wheel is actually supporting the vehicle, rather than the tire.
Run-Flat Tires Explained
Generally speaking, tires are not designed to support the weight of a vehicle without air pressure. In fact, it is the air pressure that provides the actual support. When non-run-flat tires are driven with insufficient air pressure, they develop excessive amounts of heat, which causes serious damage to the tire, and can even lead to tire failure. Run-flat tires are reinforced so that should they lose air they can temporarily support the weight of the vehicle, typically for a distance of about 50 miles at no faster than 50 mph.Deflated Run-Flat Tire
Deflated Conventional Tire
However, many run-flat tires have a speed and distance rating that is specific to them. It is best to check with the tire manufacturer to determine exactly how long and how fast the run-flat tire can be safely driven on without air.
Some vehicles are originally equipped with run-flat tires and often times these vehicles do not have a spare tire.
The Benefit of Run-Flat Tires
Run-flat tires are beneficial in that they provide safety and peace of mind to those that drive on them. With the reinforced sidewalls that a run-flat tire provides, a driver would be able to better maintain control of the vehicle if air-loss were to occur. This allows for peace of mind in knowing that you can choose when and where to deal with a tire concern versus having to change a tire in a potentially dangerous situation. Certain vehicle manufacturers have gone away from spare tires altogether as a means of eliminating the weight from not only the spare assembly, but from the tools required to change a spare such as the vehicle jack and tire wrench. This weight reduction may lead to improved handling, overall vehicle balance, and fuel efficiency. Run-flat tires can offer a higher level of reassurance and convenience that stem from the benefits they provide.
Tips on Mounting Run-Flat Tires
While run-flat tires can provide peace of mind, it is very important that run-flat tires are mounted properly to ensure the best operation. These tips for mounting run-flat tires can help make the process easier and safer.
It is very important that run-flat tires are only used on vehicles that are equipped with a functioning TPMS system. Without TPMS, drivers can potentially drive on an underinflated tire without realizing it, putting them at a high risk of tire failure.
When installing run-flat tires, it is very important to ensure that the TMPS sensor is rebuilt properly. New components, including a rubber grommet, aluminum retaining nut, and nickel-plated valve core should be installed, so as to reduce any risk of air leaks. With the possibility of bi-metal/galvanic corrosion, it is very important not to use a standard brass valve core. If this corrosion occurs, the valve core can seize up inside the TPMS sensor, often necessitating a full sensor replacement.
Tire installers should be sure to use an RMA approved lubricant while both removing and installing run-flat tires, just as they would with a regular passenger or light truck tire.
If you drive on one or more tires with low air pressure, you will want to have the tire inspected by a certified tire dealer. The heat buildup caused by low air pressure can compromise the structural integrity of the tire.
PAX Run-Flat Tires
If your vehicle has a PAX run-flat system, you will need to locate an authorized PAX dealer for both mounting and dismounting. The following vehicles featured a PAX run-flat system as an option:
2005-2009 Honda Odyssey Touring
2006-2008 Nissan Quest
2006-2008 Acura RL
2005-2009 Toyota Sienna