Aquaplaning: what everyone needs to know
Aquaplaning is one of the biggest dangers a driver can face on the road. The car practically floats over the road. This is even worse than slash-planing or icy conditions according to experts and those drivers who have faced aquaplaning.
When wet driving, water is removed out of a tyre contact patch into the tread grooves, and rubber blocks of tyres are in contact with the road surface. Tread pattern of any tyre is designed to disperse water collected in the grooves to the sides. This is not a problem when the road is just slightly wet. But if, for example, it is raining heavily, the water cannot be quickly dissipated and a layer of water builds up between your tyres and the road surface. Thus, a tyre floats up and you lose control over your vehicle: it is no longer capable of braking, turning, or even keeping the direction of movement.
What causes aquaplaning?
The problem occurs when the large amount of water cannot be dissipated from the contact patch quickly. Under such driving conditions, the wheel gradually climbs up the water wedge, in other words, on the wave that the tyre pushes in front of it. There are several reasons for this, and all of them affect the aquaplaning, delaying or bringing closer the moment when tyres stop touching the road surface:
- Driving speed. The slower the vehicle runs, the more time it has to remove water from the contact patch, i.e. drainage water to the sides along the tread grooves.
- Amount of water. A thin film of water on the asphalt is quickly removed even at high speeds, while in a deep puddle, aquaplaning can occur even at 40 km/h.
- Tyre tread. The amount of water that can be removed by the wheel from the contact patch depends significantly on the shape and depth of the tread.
- Road surface. Chances of aquaplaning are much higher if you drive along tracing ruts where water accumulates. The same is true for puddles in low and uneven areas.
- Status of a car. To some extent, the technical status of the vehicle can also influence the resistance to aquaplaning. Worn out shock absorbers increase the chances of aquaplaning. The inflation pressure should be correct, otherwise a suddenly deformed tread will not be able effectively drain the water from the contact patch. A loaded vehicle, other things being equal, will lose control later than an empty one.
Tyres as a factor of aquaplaning resistance
You should think in advance about suitable tyres, which are best used in conditions of possible aquaplaning. You can slow down driving and avoid large puddles, but first of all you should mount tyres with a deep and well-designed tread pattern.
Tread wear significantly affects the ability to resist aquaplaning. Deep and wide tread grooves hold more water, which means the less worn tyre will lose contact with the road surface later, all other things being equal.
So, according to the results of tests on wet asphalt, a half-worn tyre (3 mm tread) starts drifting at a speed of 70 km / h (its contact patch is 60% compared to a new tyre), and aquaplaning starts at 90 km/h. A tyre with a tread depth of 1.6 mm, legal limit under the traffic rules of Ukraine, begins to lose contact with the road even at 50 km/h, and at 70 km/h it is moving in aquaplaning mode. That is, the vehicle may not avoid an accident.
This is a strong reason to buy new budget tyres, but not used premium brand ones. But neither perfect rubber compound of the tread, nor its pattern will be able to remove all the water if the groove depth is insufficient, even if it is still far from critical.
How to avoid aquaplaning
- Safety speed. The heavier the rain and the larger the puddle on the road, the lower the speed should be, up to 25-30 km/h.
- New-treated tyres. If you often have to drive on highways in rainy weather, change your tyres before the tread depth reaches 3 mm. In this case, you can quite profitably sell your used tyres to those who drive slowly on country roads.
- Rain tyres. All well-known tyre manufacturers have rain tyres in their product range. Their tread patterns have wide grooves, the cross-section and shape of which are specially designed to dissipate large amounts of water. The ROSAVA product range has a passenger car tyre ITEGRO, which is good for the wet road driving.
- But rain tyres should not be understood as permission to race on wet roads, it is just an additional guarantee for a responsible driver to stay safe.
What to do if aquaplaning
Aquaplaning starts when you feel that the steering become 'light' and the car drifting from side to side. You should understand that when the wheels are floating on the water, any actions with the steering wheel and accelerator can lead to a turn of the car and loss of control. Therefore, the most important thing in this situation is to take your foot off the accelerator, don’t use the brake and hold the steering wheel firmly. When the car slows down and the tyres contact the road, you will be able to control the car. But the best thing you can do is to avoid aquaplaning.