Torque Shop: When a tyre explodes
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No running: Driving a few kilometres without air can damage the tyre's structure, making them unsafe to be reused.
PHOTO: NEWSPRESS
Shreejit Changaroth
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Is it possible for tyres to explode because of over-inflation or even when the vehicle is on the move?
Tyre blowouts are actually very rare. The structure of a tyre can be destroyed when it hits a pothole or the kerb forcefully. Most commonly, tyre carcasses are damaged when the car is driven with a flat tyre.
This is why any punctured tyre that has endured a few kilometres with little or zero air pressure should never be reused, even if the puncture can be repaired. A blowout is possible if a tyre has sustained damage to its sidewalls or general structure.
Besides impact damage, an old tyre that has been sitting on the shelf for a few years before being fitted to a car also has a higher blowout risk. This is because the rubber loses flexibility and this leads to cracks, especially on the sidewalls, once the tyre is in use.
In rare instances, tyres have manufacturing defects that may not be immediately noticeable.
The only way to prevent a tyre blowout from a manufacturing defect is to visually inspect the tyre carefully before setting off on any long and sustained high-speed drives. Watch out for bulges, cracks, chipped-off tread blocks and uneven wear patterns.
Perhaps an online search of your tyre make and model could reveal the general service life, reliability and if there have been any manufacturer recalls.
As for over-inflating a tyre, in theory, any rubber “vessel” can of course explode if inflated beyond its maximum design pressure.
However, most tyre pumps at petrol stations will struggle to achieve even 600 kilopascals (kPa), which is about six times the atmospheric pressure, because the air-compressors cannot deliver much more.
A pressure regulator and relief valve at the outlet of the compressor are mandatory for any air-compressor installation.
In Singapore, air-compressors must be inspected by a professional engineer and certified by the Ministry of Manpower annually.
Depending on the tyre size, the maximum allowable pressures commonly vary between 300 kPa and 400 kPa – and it will take at least three to four times the pressure to cause the tyre to burst. In short, it is practically impossible to inflate a tyre until it explodes.
