How Tires Fight Water to Keep You Safe


Rain Tires Need Greater Grip

The level of grip on wet surfaces is a crucial performance factor for wet weather tires. 

Unlike tires that can move easily on dry surfaces, the requirement for a stronger grip on the slippery or wet surface increases triple fold for wet weather tires.

While driving over water-logged roads, ordinary tires tend to get submerged in water, often causing the vehicle to topple or skid. 

In the case of wet weather tires, the tread is made of softer rubber that allows the rubber to heat up and generate more traction. 

This helps the vehicle stay put on wet surfaces.

That is why wet-weather tires are equipped with a higher quantity of silica or rubber content that augments their wet grip properties. 

The high silica content also helps the tires counter icy conditions during hail storms.

Deeper Grooves

Another very important feature of rain tires is their special tread pattern that can make a significant difference in how they perform on wet roads. 

The specially designed grooves help quick dispersal of water from the tire tread.

This ability to disperse water from the contact patch increases the tire’s aquaplaning resistance, which simply means the ability to stay steady and not slip on a wet surface. 

A greater aquaplaning resistance also translates to a better grip on wet roads and easier handling capabilities.

Apart from the specially designed grooves, for water dispersal, rain tires also have other features such as special tread blocks and cuts to channelize water away and improve road adhesion.

The Challenge in Developing Wet Weather Tyres

Interestingly, rain tires are not the standard fitments on factory-finished vehicles! 

This is because; for a superior grip wet weather tires need greater friction, for enhancing grip. 

This results in increased rolling resistance for the tires, which in turn increases fuel consumption and brings down the fuel economy. 

And of course, increased fuel consumption also means more harmful emissions into the environment.

Hence the challenge in developing wet weather tires is achieving a balance between these two parameters. 

Luckily for us, tires manufacturers are investing in R&D efforts and the emergence of innovative tire technologies has made this a reality for several tires.

For instance, in the Michelin Energy Saver tires, known for their fuel efficiency, Michelin has incorporated the Durable Security Compound, a patented ingredient complex into the tread compound so that wet grip is not compromised.

The New EU Regulation on Wet Weather Tyre Safety Norms

In a country like the UK, wet weather exists most of the year. Wet weather or rain, tires are always in demand. 

That apart, the new EU regulation also states that tires need to now showcase the EU tire label which includes a rating for wet grip and braking performance.

Tire labels are marked from categories A to G, with ‘A’ suggesting shorter braking distance in wet weather and ‘G’ allowing the longest wet weather braking distance.

For instance, this tire below has a rating of ‘B’.

So a tire with an ‘A’ rating has the best-wet braking ability and that with a ‘G’ rating stops 18 meters farther (than the A-rated tire) when brakes are applied.

Wet grip is rated from A (category with the shortest braking distance) to F (category with the longest braking distance).

Ratings D and G are not used for passenger cars.


Why the wet grip rating matters

A few metres can make all the difference in an emergency. A set of A-rated tyres will stop 30% shorter than a set of F-rated tires.

For a passenger vehicle applying full brakes from 80kph, that’s 18 metres shorter braking distance.*

Note: You should always respect the recommended stopping distances when driving.

READ: Learn How to Read Your Tire Sidewall

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Published by
The Engineer

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