Rain tires: types, features, advantages
Well-known manufacturers of car wheels, relatively recently expanded the line of their products. Numerous types of summer and winter rubber, complemented the category of rain tires. It happened in the transition from XX to XXI century. Aquashines had been under development since the seventies, but the project remained on paper. The idea was recalled much later. Reanimators of forgotten technology became engineers of Formula 1. Racing industry pushed the leading tire manufacturers on a promising concept. Thus the market was replenished with an additional model of highway tires for driving in the rainy season.
Goodyear was the first company, which introduced the rain tire model “Aquatred”. The manufacturer began producing aqua tires in small batches in 1991.
Features and advantages of rain tires
Rain rubber is a subset of summer wheels. Therefore, there is no general classification labeling for these tires. However, some manufacturers put a mark on the product: “Aqua”, “Rain” or an umbrella symbol. If there are no markings, the buyer can recognize the aqua tire by the tread pattern, which is reduced to the center of the tire by a herringbone, in the form of the letter “V”. Since we started talking about the configuration of the tread, then we will go straight to the disadvantages of rain rubber:
- Noisiness. As many drivers know, the tread pattern “V” is characterized by increased noisiness. This drawback reduces the demand for tires of this type. Although, it is possible to find less noisy aqua tires with an asymmetric tread pattern on sale;
- Discomfort. The low side profile, not exceeding 60 units, more distinctly transmits the road unevenness to the suspension, which reduces the comfort of operation;
- Price. Wheels are produced in small batches, and such exclusivity increases the final cost of the product.
But all these disadvantages pales before the main advantage of the rain tires – resistance to aquaplaning. In driving schools, teachers call this effect “water wedge”. What does it mean? Driving into a puddle in a regular road tire, at speeds over 70 km/h, the tread cannot cope with the diversion of water from the contact patch of the wheel with the road. As a consequence, there is a slip on the surface of the puddle. Loses control and the car risks skidding.
Aqueous tires do a good job of draining and counteract the formation of a “water wedge”. The wheels retain grip with the road surface, even at speeds over 100 km/h. An exception – overcoming deep puddles at high speed.
Tread design of rain tires
Why are rain tires equipped with a V-shaped tread? The fact is that this is the simplest and most effective form of water drainage on both sides of the wheel. This tread looks similar to the pattern of summer wheels. At the same time, it is distinguished by wider diagonal grooves and deep radial channels. Water that enters the radial channels is instantly pushed out to the sides through the arrow grooves.
Engineers have discovered that the better the performance of a rain tire on a wet road, the worse its traction with dry asphalt.
Grip Index in the Wet
All manufactured tires are marked with a wet braking traction index. The designation is printed as “Traction” on the side profile with additional letters: A, B or C. The first lettering stands for better braking performance. But, if you meet a double “AA” it means that the tire in question has better traction qualities. The “Traction” marking can be found between the “Treadwear” and the “Temperature” overheat indices.
Experiencing a strong desire to buy rain tires, you should consider their disadvantages. Perhaps summer tires with a V-shaped tread will provide decent grip on the wet road. However, if you live in rainy regions and are often on the road, information about rain tires should be taken into account.
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Peculiarities of selection of rain tires for cars
There is a perception that the danger of skidding and loss of controllability of the car is the prerogative of winter roads only. Ice – this is indeed a serious threat, but by no means the only one. There is such a concept as aquaplaning, which is also applicable to the warm season. In regions with an irregular amount of precipitation, it is a very serious factor, forcing drivers to take certain measures to improve the safety of driving on wet asphalt.
Among the most effective ways to combat such a phenomenon is the use of rain tires – a kind of summer rubber, which effectively prevents the tires from sliding on wet asphalt.
Strictly speaking, any driver should have a set of such rubber in the garage – it rains in all regions, even in the Sahara. Of course, all spring and fall season with such “shoes” for your car is like walking half a year in seasonal boots, but in spring and fall, when dry roads are more an exception than a rule, the rain tires will be very helpful. By the way, the statistics in this regard is inexorable – the accident rate on wet roads is several times higher than on dry ones.
What is aquaplaning
First of all, we should define what is meant by the term “aquaplaning”. The word “aqua” does not need translation, but what does planning have to do with it, you may ask? The question is that while driving at high speed along the road, soaked through with a downpour, there really is a hydrodynamic wedge between the tire surface and a road surface, which creates the effect of tire elevation, due to which the normal traction of a vehicle in the contact patch is lost. And this is a direct way to loss of controllability, which is dangerous even when driving straight ahead, let alone steering. Which, by the way, is required almost all the time, not so much because of the bad settings of the car, but because of the non-ideal geometry of the track.
The only relatively effective way to combat aquaplaning is to ensure the rapid removal of excess water from the contact patch of rubber with the road. It should be noted that this effect appears at speeds of 80-100 km/h, but a number of factors (poor condition of suspension units, insufficient or increased pressure in tires, critically low tread depth) may reduce the threshold of aquaplaning up to 40-50 km/h. The probability to skid when entering a deep puddle is very high.
The driver’s skill will not be able to prevent the beginning of loss of controllability. Abrupt braking is also not able to stop aquaplaning, especially on rear-wheel drive cars. Moreover, even the presence of DSC/ABS systems, supplemented with digital safety programs, will hardly help you.
So what is left? The arsenal of measures, helping to reduce the risk to hit the ditch or drive oncoming traffic, is poor:
- Driving around puddles is the right tactic, but it doesn’t always work. To be more exact, it is possible to bypass a vast part of the road flooded with water only in those cases when the oncoming lane is free and the puddle does not occupy the whole width of the carriageway;
- speed reduction is even more effective, but it is hardly applicable on country roads;
- But a special rain rubber will allow you within a reasonable limit not to limit themselves in the speed mode and not to make unnecessary maneuvers at high speeds.
Labeling of rain tires
Currently, aqua tires are not a separate kind of car tires, unlike summer or winter tires. For the first time rain tires appeared not long ago – in 1991, adding to the range of well-known company Goodyear. Currently, the production of such rubber mastered even domestic producers, but as for labeling, then there is no single standard in the absence of classification simply does not exist.
Some manufacturers label such products with the inscription “Rain” (rain), others use the word “Aqua”, some – the image of an umbrella.
But you can always tell the rain rubber from the ordinary summer – the presence of wide and deep longitudinal grooves, uncharacteristic for conventional tires. Usually, such a groove is located in the middle of the tire, and diagonal grooves run from it, whose task is to quickly remove a large amount of water from the contact patch.
But the physical laws cannot be defeated – the presence of a deep groove worsens the grip properties of the rubber, reducing the active contact area. As a result, acceleration and braking characteristics deteriorate, and the tires themselves wear out faster. Since rain tires tend to be low-profile, the deterioration of driver comfort is another obvious disadvantage, as is the higher cost of such a set.
But are there real alternatives to rain tires? If you live in a southern region, where the off-season period is short, and the amount of precipitation – to a minimum, it is justified to use all-season rubber, “geared” to the wet asphalt:
- introduction into the composition of the rubber mixture of the so-called “active soot”;
- Asymmetric tread;
- shifting the tread pattern in a diagonal perspective;
- the presence of several longitudinal grooves.
Alas, but most of the country does not fall under the above weather criteria. So rain tires are quite a justifiable purchase for most car owners.
Now let’s talk about more down-to-earth things. Conventional rubber has a composition that is optimally tuned for the average road surface. And it is quite suitable for driving on wet asphalt at maximum tread depth, i.e. in the unworn condition. But, alas, the tire does not stay new for long – the intensive exploitation of the car adversely affects its ability to keep the road.
Modern tires have a wear indicator, which helps to determine the moment when you can no longer use it. Alas, many representatives of a huge army of motorists decide to buy tires only when they become absolutely bald, or when the cord starts sticking out. Aquaplaning starts much earlier than the index of critical wear. In particular, a number of tests showed that the tread depth of less than 8 mm is enough, so that at 70-80 km/h on a wet road the car partially loses grip. 4 mm and less – it is already really dangerous.
And if the depth of the drawing is less than 2 mm, then the 5-millimeter layer of water machine is skidding at about 60 km / hr (for the new rubber effect is observed at speeds from 90 km / hr).
So the rain tires can be called if not ideal, then a very effective way to combat aquaplaning. Provided that you monitor their condition and buy a new set of time, as soon as one or more tires orderly worn out.
History of rain tires
When they talk about the difference between the summer tire and the rain tire, it should be clear that the latter is a kind of summer tires. So the formulation of the question itself is not quite correct, although we understand what we are talking about. We have already said about the characteristic features of aqua tires – the presence of deep and wide longitudinal grooves, and the presence of a large number of side channels, designed to divert water to the sides.
Certainly, and purely summer variants may have similar, though not so pronounced elements of tread pattern, so all of the above should be perceived as with a certain degree of relativity. Availability of corresponding marking may help not to make a mistake, but you should not rely on consultants’ assurances: their task is to sell goods, especially stale ones.
The safety of cars when driving on wet roads was discussed intensively in the second half of the last century. The concept of aquaplaning was first mentioned in the sixties, in the seventies the idea of a car tire which could effectively resist a water film was proposed to manufacturers, and from that moment the development of an optimal tread and composition began.
As is often the case, the first rain rubber for cars was tested in Formula 1 races, where it was successfully run-in and deemed suitable for use. As a result, today there is not a single major manufacturer of car tires, which would not have models without rain marking in its range of seasonal goods.
It should be noted that the first samples had performance characteristics that did not allow attributing such rubber as the main one. But over time, companies specializing in the production of tires managed to improve the composition (by introducing “active soot” capable of absorbing excess water) and the pattern so as to better resist aquaplaning without significantly worsening the braking distance and the wear of the tread.
The latest generations of summer rain tires are products designed for active use, for an aggressive driving style. Developments are underway to reduce the noise level created by such rubber on the wet track. And it is again a struggle at the level of compromise.
Top 5 best rain tires
And yet the question of rain tires choice is not abstract, because no one wants to buy “a pig in a poke”, and the information on the subject in the network, frankly speaking, a little bit.
Therefore we decided to give a small rating of the best rain tires, compiled on the basis of a number of specialized tests:
- The rubber K120 Ventus V12 with index Evo2 from the company Hankook heads our TOP. Four longitudinal grooves are provided for water collecting, for its drain – a set of multidirectional slots, which cope with their main task very well. The model topped the rating not only because it effectively fights the slip on the wet roadway, but also because it has excellent acoustic characteristics and practically does not complicate the driving. But that’s not all: due to thoroughly selected composition, K120 Ventus turns out to have one of the most impressive durability among the modern representatives of the aqua tire subclass;
- The rubber UltraContact UC6, developed by Continental brand specialists specifically for use in rainy weather, was slightly inferior to the leader. This novelty also has an asymmetric pattern, including five sides with different configurations. The central grooves are made with slightly beveled edges, which allowed reducing the braking distance, as compared to the competitors. The number of longitudinal grooves, like the leader of the rating, is four. In combination with the effective pattern of the other segments, a very effective drainage system is achieved, which allows you not to reduce speed when driving through deep and long puddles. This also features an innovative rubber compound formula that improves the tire’s grip properties on wet asphalt;
- Nokian Hakka Green tire took a decent third place. The drainage system of this tire is represented by the same four central strips, which are complemented by deep radial grooves, located in the marginal shoulder sectors of the tire. The rubber is characterized by excellent dynamic performance (acceleration/deceleration) and environmental performance (reduced fuel consumption) – the Finns are smart about it;
- Eagle Sport rain tires for cars from the pioneer in this direction, the company Goodyear, as the name suggests, designed mainly for speed lovers. And here we are dealing with four deep longitudinal grooves, complemented by a large number of transverse and diagonal recesses, allowing effectively get rid of large volumes of water. An important advantage of this model is its quietness, as well as good durability;
- CrossClimate from Michelin brand is one of the few rain tires, belonging to the all-season class. So, its owners can be calm about driving on wet roads, but this tire also copes well with slightly snowy roads, providing good braking thanks to the developed system of drainage grooves, which are directed from the central to both sides.
We hope that you will draw the right conclusions from the above mentioned. In any case, information about rain tires will not be superfluous, even if you do not plan to buy this product in the short term.