EXPLAINER | Why the exploded tyre on the back of that Ford Ranger caused so much damage

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• A tractor tyre exploded at a Kwazulu-Natal filling station earlier in November.

• The incident garnered widespread concern from industry experts.

• Tyre maintenance is an important aspect of vehicle ownership.

For more motoring stories, go to www.Wheels24.co.za

A video recently surfaced of a tyre exploding on the back of a Ford Ranger bakkie. According to News24, the driver of the bakkie was in the process of filling a tractor tyre with air when the explosion occurred. The blast was so violent that it severely damaged the bakkie and sent the driver into the air, and to the ground. Judging by the aftermath, the driver was lucky to escape with his life.

The accompanying images tell a different story to the video. The Ranger's loading bay is completely destroyed, and the tailgate came off its hinges. The rear lights and window separating the cabin and loading bay have also been shattered. The incident brought activities at this Kwazulu-Natal filling station to a complete halt.

On reviewing this video, the South African Tyre Manufacturing Conference said: "The SATMC urges consumers to adhere to safety precautions when inflating commercial tyres. These tyres should be inflated in an inflation cage. Consumers should also make use of accredited tyre dealers in order to receive adequate technical advice and service on their tyres."

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Tractor tyre exploded on back of Ford Ranger.

Filling a tyre with air

When a tyre is deflated, our instinct is to fill it with air, especially when the unit is still in a working condition. Using either a domestic pump or visiting your nearest filling station, we set about the process of inflating said tyre. However, what many of us are probably not aware of is that each tyre has a maximum amount of air it can take.

These readings, or indicators, can be found on the inside of the driver's door of your vehicle. If not there, you can find it in the vehicle's manual. Using the air gauges at the filling stations, one can see how much air has been pumped in or how much longer you must still go. Some stations' electronic devices allow you to enter your desired air pressure and will beep upon completion. The amount of air pumped into a tyre is measured in bar or PSI (pounds per square inch).

Tyres also give readings on their sidewalls, including how much air it can take (psi). However, these are the maximum readings of what the tyre can handle, and it is recommended that you do not add this amount of air to the tyre. Verging on the maximum reading can result in the slightest bump or knock exploding the tyre. The readings in the door or manual are the safe options.

These tips apply to all types of tyres, including tractor tyres.

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Tractor tyre exploded on back of Ford Ranger.

Why did the tyre explode?

Tyres have different codes written on them that guide you as to what extent it can be used for. These codes indicate what type of tyre it is (passenger car, light truck, motorcycle, etc.), as well as its size, the load index, and the maximum speed it can operate at. And then, of course, how much air can be pumped into it.

The same codes apply to a tractor tyre, but it is safe to assume that the driver who was pumping the tyre was not aware of the maximum air he could pump into it. Sadly, it is not just this driver who will pump a tyre 'until it's hard', but a common misinformed practice by many around the world.

MasterDrive said to Truck and Freight: "Tyre damage due to underinflation cannot always be detected by external inspection. If a tyre fails during inflation, the explosive force can be released resulting in a destructive air blast and the ejection of high-speed particles. If the wheel is not restrained, it can fly through the air. The rapid release of this explosive force from a ruptured tyre can result in serious injuries or even death. This person was lucky to only get away with damage to their vehicle. That person could have lost their life!"

tractor tyre,ford
Tractor tyre exploded on back of Ford Ranger.

Health and safety

Truck and Freight lists the following health and safety protocols:

• Heavy-duty tyres should be inflated in a cage as substituting the hazard with one that is of lesser risk - for example, if a truck tyre has been identified as underinflated while in use, do not immediately re-inflate the tyre in-situ. Instead, fully deflate the tyre and replace the wheel with a spare and have the tyre inspected by a competent person to determine if it is safe to put back into service.

• Isolating the hazard from workers: deflating tyres prior to them being removed from the machinery or vehicle and inflating tyres in a safety cage or other portable restraint device; never reach into the cage during inflation or deflation and always position the body to one side of it.

• Implementing engineering controls: for example, by fitting - long enough air hose with a clip-on valve nozzle and remote pressure gauge for workers to stay outside of an exclusion zone (i.e. the potential trajectory or explosion zone), and a remote dump valve that is capable of rapidly deflating the tyre in an emergency.

Any remaining risk must then be minimised by using administrative controls such as:

• Have a regular tyre maintenance schedule which checks tyres for condition, matching, pressure, tread depth and wear patterns, as well as rims for corrosion or cracking.

• Always follow the recommended tyre servicing procedures and ensure all workers undertaking these procedures are trained and follow them.

• Inform, train and supervise staff in safe personal positioning and safe procedures during tyre inflation including actions when a potential tyre failure is identified.

• Potential trajectory paths from a failure and exclusion zones have been identified.

• The wheel is inspected for damage and corrosion prior to the refitting of tyres.

• Tyres (new or used) are inspected for defects.

• Workers stand outside of any exclusion zones.

• Tyres are only inflated to the recommended pressure.

• All safety cages, air-lines and associated equipment are suitable for the task and maintained in a safe working condition.

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