On the evening of 27th March, a Tata Safari Storme jumped the median, and hit an oncoming truck, killing five people instantly. This incident happened at Karakodahalli, near Dharmapuri. Four were from the SUV, and one was the cleaner of the truck. A woman occupant of the SUV is fighting for her life at a hospital. So, why did the SUV jump the kerb, and hit the truck? One of its tyres burst, leading to the driver losing control of the 2 ton vehicle. Yes, a tyre burst is one of the major causes of high speed accidents, and consequent road deaths. Here’s why a tyre bursts, and here’s how you can prevent one.
Why does a tyre burst?
1. Underinflation is the major cause of a tyre burst. The sidewalls of an underinflated tyre flex. This flexing weakens the tyre structure and adds to the heat that the tyre has to endure, together causing it to burst.
2. Damaged tyres with sidewall cuts and bulges aren’t fit to be run at high speed. Driving at high speeds on such tyres increases the stress on the failure points (sidewall cuts and bulges), causing bursts. Also, worn out tyres can lead to overheating at high speeds, causing bursts. The same is the case with tyres with bald spots.
3. Overspeeding, is another cause of tyres blowing out. Every tyre has a speed rating that needs to be adhered to. Never exceed 80 % of the tyre’s rated speed if maximum safety is your concern. Overspeeding drastically reduces tyre life as heat dissipation at high speeds is a major issue. This causes the tyre to overheat and burst.
4. Overloading is one more cause. It results in sidewalls of a tyre undergoing a lot of stress through flexing. This flexing weakens the tyre and also results in it overheating, eventually leading to a burst.
5. Super hot roads, especially built of concrete can get very hot in the summers. High speed driving on such roads is an invitation to disaster as the tyres may not be able to dissipate heat fast. Slower dissipation of heat means higher chances of the tyre overheating, and bursting.
How to prevent a tyre from bursting?
1. Well maintained tyres can save lives. Make sure that your tyres are in good shape. Tread depth must be at an optimum/safe level. There shouldn’t be bulges or cuts on the sidewalls. Generally, a tyre’s life is about 6 years. A tyre older than 6 years should ideally be replaced, irrespective of the mileage covered.
2. Maintain optimum air pressure. Crucially, get air pressure checked when the tyre is cold, which means after covering less than 3-5 kilometers from a cold start. Check air pressure regularly.
3. Don’t overspeed, or for that matter get close to the tyres’ speed rating.
4. Don’t overload your car.
5. Maintain speed limits. They exist for a reason. This is more important in case of concrete roads in summers, as they can get really hot.
6. Don’t buy poor quality tyres just to save some money. Obscure brands are best avoided. Opt for the Indian/Foreign makes with BIS marks.
7. Drive in the middle lane or left lane of the road. This gives you more space to maneuver in case of a tyre burst.
8. While driving at highway speeds, take frequent breaks as this helps the tyres to cool down.
What do you do in case your car’s tyre bursts?
1. Do not brake hard. This may sound counter-intuitive but hard braking during a tyre burst only destabilizes the car further, especially when it’s driving only on 3 wheels. Don’t touch the brake until you have established steering control.
2. If you’re on a straight road, hold on tightly to the steering wheel and allow the car to coast to a stop. The idea is to keep the car as stable as possible.
3. If you have a curve approaching, steer in the opposite direction as a car with a burst tyre generally pulls to one side of the road. However, the steering must be gradual and the brakes mustn’t be touched until steering control is regained.
4. All your inputs – accelerator, brake or steering – must be gradual in this high pressure situation. Large steering and braking inputs will only cause the car to go out of control. Experience and a calm mind certainly helps.