Punctured your tyres due to rocks or spikes on the road? Here’s what your tyres are capable of to potentially get you away from danger
[Durban, South Africa, 20 January 2025] With the rise in road spiking incidents, where sharp objects are deliberately placed on roadways to damage vehicles and target unsuspecting drivers, safety on our roads has become a pressing concern.
Dunlop Tyres SA’s leading technical tyre expert, Keith Phelps, provides the following key information for drivers – presented in a Question & Answer format below – to unpack how tyres respond to such situations, and offers practical advice to help drivers make safer decisions during emergencies.
How will a driver know they’ve driven over something that has impacted their tyres?
When a tyre is penetrated, a hissing noise would be heard, and the vehicle would suddenly pull to the one side of the road, or a vibration will be felt on the steering wheel of the vehicle.
What happens when a tyre hits a spike?
A tyre is designed to contain air and when it’s severely impacted against a low-lying object or is driven in a very under-inflated condition, the steel protector breaker plies are broken, resulting in a sudden deflation that we call run flat tyre damage, that is the tyre fails when occurs. The tyre cannot be repaired as its casing or carcass integrity has been affected. Please note that if the tyre is repaired and placed back into service, the tyre will fail.
Does speed play a role in the type of damage sustained?
If the driver of a vehicle collides with a large object at a high speed, it can result in the tyre bursting and the driver losing control of the vehicle. On the contrary, if the driver had been driving at a low speed, the tyre would be able to withstand the impact due to the flexing of the sidewall area of the tyre, resulting in the driver having increased control of the vehicle and the tyre may not burst.
What happens to the tyre and its structure upon impact?
A sudden deflation will result in severe run flat damage occurring, which negatively compromises the inner liner of the tyre, and the carcass or casing plies would be damaged. Due to the tyre having insufficient air inside it, the vehicle’s handling will be impacted, such as pulling to one side, or unusual vibrations will be felt on the vehicle’s steering wheel. The vehicle would not brake which can result in the driver losing control of the vehicle. When a sudden deflation of a tyre occurs, do not brake. Rather, continue to hold the steering so that vehicle can travel in a straight line. When brakes are applied suddenly on a vehicle with a flat tyre, a sudden weight shift occurs from the rear of a vehicle to the steer axle, which can result in the driver losing control of the vehicle. My view is that you’d rather lose the tyre, than lose control of the vehicle.
What if I don’t want to step out of my car to check my tyre damage?
If you feel vulnerable, especially with the context of road spiking, and don’t want to stop and get out of your vehicle to inspect the damage, continue to drive on the flat tyre until conditions are safer. Alert local law enforcement if you had seen something suspicious on the roads and call a family or friend to alert them of your situation and share your live location if possible. Try and drive to a place of safety. Please remember that tyres and rims cannot be repaired and must be replaced.
Can I drive on a punctured tyre?
Only in these types of situations, continue driving – and I’d recommend driving at 30-40km/h to get out of a potentially dangerous situation to safety. Do not “floor it” as an instinctive measure to get out of danger. However, note that driving on the punctured tyre would result in severe run flat damage which can result in casing or carcass breakup depending on the weight of the vehicle and the speed. Sparks may come off a steel rim when the rim contacts the road surface. With an alloy rim, no sparks would occur, however, as alloy rims are softer, more damage would occur. The casing integrity of your tyre will be negatively affected and will distort the casing plies which means the tyre cannot be repaired.
Is there a difference between having one tyre damaged, or many, and is one tyre(s) more important than the other(s)?
All four tyres are important as it’s the air inside the tyres that carries the load of the vehicle, and not the tyres. No tyre can react or perform with insufficient air inside it. However, you have less control over the vehicle if the steering axle tyres are impacted or spiked. This affects the braking ability on the steering axle tyres of a vehicle. The tyres would be negatively compromised, and the overall handling characteristics of the vehicle would be compromised. 70% of a vehicle’s braking ability is obtained from the steer axle of a vehicle. If the rear axle tyres are spiked or impacted, you have more control over the vehicle as 30% of a vehicle’s braking ability comes from the rear axle tyres.
Are newer technology tyres designed to withstand such impacts?
While modern tyres are designed to be durable and safe, no tyre can fully withstand deliberate spiking. Some manufacturers of high-end vehicles and military vehicles fit run-flat inserts into their tyres, but this is not common due to the expense of the manufacturing process. Motorists have the option to put after-market tyre sealant inside their tyres which will buffer the impact of small screws and nails should the tyre be compromised. However, the tyre sealant may not be effective against the size of the spikes being placed on road surfaces.
What tyre products or tools can I carry to repair my tyre?
Carrying a temporary repair care kit is advisable, however, it is only a temporary repair and should not be left in the tyre. I suggest carrying a small compressor which will work from the battery of the vehicle and can inflate the tyre adequately.
How do the right tyres and regular tyre maintenance help minimise impact?
Think how you need to continuously build and maintain a strong immune system to fight off illnesses and colds. In the same manner, your tyres need to be in good health to withstand an impact. You need to do continuous maintenance to ensure it’s in good health. If you are using the wrong tyres for your vehicle, and for what you put it through, you are compromised. Severe off-road conditions require a 3-ply sidewall tyre which is more conducive versus a standard radial tyre. Consult a tyre expert at your local tyre dealer to ensure you fit the correct tyre for the correct application you are travelling in. If your tyres are not properly inflated and have bulges etc., then it’s already compromised and poorly able to withstand an “attack” such as spikes.
Tyre maintenance advice:
Tyres should be inspected for potential vulnerabilities or damage once a week.
Regular tyre cold inflations should be carried out at least once a week when the tyres are cold. Proper tyre inflation pressures are crucial as this will provide the vehicle with better handling and cornering and braking characteristics and assist with fuel consumption.
Ensure regular wheel alignment and balancing checks.
Have your tyres rotated every 8 000 to 10,000 kms.