Bridgestone South Africa

The RFT Tyre

Ever wondered what happens when a tyre losses air. Well, a tyre that lost it's air either through a penetration or a cut to the tread or sidewall area will result into a loss of control of the vehicle or the driver will have to stop to change the tyre. With Bridgestone's new Run Flat Tyre Technology (RFT), Bridgestone can give allot more safety and comfort to the vehicle users in South Africa and the rest of the world.

The safety, comfort and convenience of Run Flat Technology 

It's not difficult to see why more and more car manufacturers are fitting RFT tyres to their new models. The first safety benefit is that if a vehicle in motion suffers a rapid loss of tyre pressure, RFT enables the driver to maintain and possibly avoid a potentially fatal situation. Secondly, RFT tyres enable the driver to leave the risk area, continue the journey, and avoid the dangerous habit of jacking up the vehicle on the roadside.

RFT also provides more comfort and convenience for the motorist. Within the specified speed and distance limits (typically 80 Kpa for up to 80 km), the driver can either complete his journey or travel to the next qualified service station, with no worry about having to change a flat tyre.

How does the RFT Tyre work?

The sidewalls of the RFT tyre have embedded reinforced and heat resistant rubber strips. These strips prevents the sidewalls of the tyre to collapse in the case of air loss. The special EH2 rim further prevents the beads from slipping off by keeping them firmly in place. So you can safely drive with control and comfort to an area where the tyre can be changed. 

The Construction of the RFT Tyre

Two of the areas Run Flat Technology focuses on are rigidity and heat resistance, so that the tyre can support weight when it is rotating with total air loss. Bridgestone's new RFT Tyre meets this challenge with a combination of design, materials and construction changes that optimize the location, shape and physical property of each tyre component:

  • The sidewall is constructed with reinforced rubber, carrying the vehicle's weight at zero-pressure;  
  • The bead shape configuration itself is unchanged, so that the Bridgestone RFT tyre is compatible with conventional rims - a significant long term advantage of Bridgestone's patented RTF. The bead wire is nevertheless wider and reinforced, ensuring a secure fit on the rim even at zero pressure, and a special bead filler with low heat generation is used.

The Conditions of Using the RFT Tyre 

Can the Bridgestone RFT Tyre be fitted to any vehicle?

Whilst physically possible – we strongly recommend not. Bridgestone does not recommend fitting RFTs to vehicles which have not been specially designed for RFT.

Reasons:

  • The driving capabilities under zero pressure need to be carefully evaluated. Depending on the specific vehicle handling and weight & force contribution the possible speed or distance limits can vary significantly.
  • Additional RFTs demand a working & reliable TPMS (Tyre Pressure Monitoring System) to be installed. A tyre deflating or operation at zero inflation pressure may not even be felt by the driver thus giving you no warning of the problem that has occurred. TPMS systems ensure you are advised that a tyre has deflated and can take the necessary action (slow down, head for nearest replacement centre within the driving distance allowed).

Speed and Distance during RFT Operation

It is recommended that during the run flat situation that a speed of 80km/h is not exceeded for a distance of  80 km.

Can Bridgestone RFT’s be repaired?

RFT tyres are in principle not possible to be repaired. Reason: During operation after having a puncture the tyre will experience an abnormal stress situation. Depending on driving style, speed, load, distance and road conditions it could generate irreparable damages or weakening of tyre construction which might not be visible from outside. After tyre has been run under-inflated, or with zero pressure - as with any other tyre - it is rendered unserviceable.

Since safety is a key priority for Bridgestone, it is our recommendation not to repair RFT tyres once the tyre experienced such conditions.

Changing Sizes 

When fitting new RFT tyres to a vehicle please keep the following in mind.: 

  1. Always ensure that the size is correct.
  2. Confirm that you fit a Run Flat Tyre and not a conventional tyre with same pattern and size. Confirm RFT tyre by checking the sidewall for the RFT mark. 
  3. Ensure tyre is mounted to the rim by tread design. RFT Tyre may be Direction Tyres, which the direction of travel will be indicated with an arrow on the sidewall, or RFT Tyre may be Asymmetrical, which will be indicated on the shoulder with "Outside" and "Inside" The outside should always be fitted facing away from the vehicle or on the rim face side.
  4. Confirm that Load Index and esspecially Speed Symbol is the same as the original RFT tyre that was removed. Tyres with the same size and pattern may differ in Load Index and Speed Symbol.

Vehicles with Sensors only

Some vehicles in our market is fitted with Tyre Pressure Monitoring Sensors only. The system work with conventional tyres and is there to inform the driver of a tyre that is loosing pressure. 

These sensors can either be a "Valve and Sensor Unit" or a Sensor strapped to the inside of the rim.

Special care is needed when Mounting or De-Mounting a tyre to a rim where a pressure sensor is used. (see mount & De-Mount Procedure for RFT Tyres and Wheels equipped with sensors)

Equipment Required (information for tyre dealers)

Mounting of the Bridgestone RFT, Basically, due to the self-supporting sidewall construction the tyres have a more rigid carcass than a regular/ standard tyres without RFT technology. But nevertheless, Bridgestone experienced in several tests, the tyres can be mounted and de-mounted on the same machinery which is capable to mount standard ultra low aspect ratio tyres.

Special care is needed if a Pressure Sensor in side the wheel.

Standard tyre Mounting and de-mounting equipment can be equipped with a hydraulic aid to assist with the fitment of a RFT tyre.

Please contact your Mount and De-Mount Equipment supplier to assist you in the compatibility of your equipment and any additional equipment required. 

You will need the following accessories to go with your current Fitting Equipment. 

  1. Hydraulic Help Arm
  2. Plastic sleeve for Bead lever 
  3. Plastic sleeve for Bead Breaker Shoe
  4.  Plastic Protection for turn Table Clamp
  5. Plastic Insert (Grommet) for Mount/De-Mounting arm' 
  6. Bead Clamp
  7. Fitting Instructions

Mount and Demount of wheels fitted with Tyre Pressure Monitoring device 

Special care needs to be taken when mounting or demounting RFT tyre and Conventional tyres fitted with Tyre Pressure Sensors.

Bridgestone South Africa

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