What is the grip, and where does it come from? Why does a car “ears” in the first turn? TopGear help you capture the essence of the problem
So it is not just a test of tires. We’re not going to read boring lectures on physics coupling, rubber compounds and how specific protector behaves on the asphalt. You only need to know the basics: it is important to engage all. Size, weight, center of gravity and all that stuff, as well as whether the suspension is able to keep the tires in contact with the road. After tires, which now and then jump in the air, no clutch can not give. (Yes, Mini JCW!)
And you have to remember that in addition to the bus must be able to grip. Very well when the tires go quiet, smooth and straight, do not explode and extinguish irregularities, not hunched under the weight of the machine. In short, these four little contact patch is always very, very busy.
And today they have a lot of worries especially. Our idea is simple: take the car and put it on four tires, we go, something which counts forward, then we go to the next set and give a subjective assessment of what they differ. Count – my job. A rush on Dansfoldu collecting information will be our junior researcher, never removing white robes. Can get very interesting. Come on, Stig!
We also have other purposes. We want to know whether the tires affect the dynamics of the machine. To do this, we measured the acceleration and up to 60 miles / h, and the stopping distance from 60 miles / h A more interesting to know whether there is a difference in the noise and lateral loads which can be developed with each set.
No matter how fast or did your master, he is not fast enough for Stig
So tires. Same size: 215/45 R17. This is a standard dimension for our Subaru BRZ, which the factory shoes in the same bus as the Prius, – “eco-friendly” Michelin Primacy. There, they are not made of natural rubber. But made so that there is less consumption and emissions of CO2. It is not so difficult – just need to frame and tires were hard, and then the resistance will be less. But they cling to the asphalt worse.
In our test, Michelin – a sort of middle ground. But what if you put on the Subaru sports tires? Step forward, Continental ContiSportContact 5! And then we become arrogant and decided we should try and tires for track days: Yokohama Advan AO48. They look crazy, but on the road, however, is legal. And the last set – low Arrowspeed N1000. Put otbalansirovat and all four of these tires can be the price of one “Yoki”. But here we do not expect great things.
While these tires are brand new, they behave like the others: not too hoot and pretty well cling. Problems arise after a couple of quick laps. Protector is heated, then overheats and just peeled off. Thank you, Stig, for science! Over the same number of laps Arrowspeed demolition twice, three times stronger than Michelin or Continental. Under normal circumstances, this would require thousands of kilometers. In the limit of N1000 bent and spoil the purity maneuver BRZ, which gives us even “civil” Michelin.
Primacy tires should have an advantage in the test, because it was set up under the BRZ them. And the result is exhilarating. Cornergrip excellent: in the hands of the Stig machine was able to develop good lateral overload. But best of all is that when you have reached the limit, the tire grip is not weakened at once – have time to notice. In addition, Michelin was the most quiet and Subaru behaved naturally and friendly.
The first thing to understand why the tires begin to slip when accelerating, braking or cornering. Maximum grip, which can provide each tire, proportional to the weight per wheel, and the coefficient of friction between the tires and the road. In a move that is shared between a maximum transverse and longitudinal loads. In turn, for example, there is a lateral force, because that reduces the possibility of braking. Conversely, when the maximum heavy acceleration tires keep the car on the bad path. This balance is well demonstrated by the friction circle, which describes their vector sum.
As with tires Continental. At first we thought that the full-fledged sports rollers – it’s too much for the 200-strong BRZ. Excessive tenacity spoil a pleasant balance of power and grip, which gives Michelin … but we were wrong! Yes, sometimes disrupt the car into a skid was difficult, but what does it mean in the real world? A Continental keeps incomparably better and sharper rulitsya Subaru. And the output of sharp turns, you can feel how the differential. Great job.
Remained Yokohama. But we took these out of the van five minutes slicks, we sprinkled a rain. Hmm, yes, in the rain without tread bad … However Advan was a revelation – to the asphalt tires clung so tenaciously as the Continental. But the picture is different puddles – poluslik that expected, do not like water.
They are generally very specific. On a normal road Subaru with the same success can be shod in a toothy off-road tires – so they rattled off a smooth Danfolda. And on the track, where their grip almost shocked, no less shock came when Advan in turn keep longer. Suddenly, without warning. With tires Yokohama BRZ became just another car – difficult to manage. These tires may well be used for track days, they are not only well-kept road and did not wear out, but will also give the car a new, fascinating character. And srezhut four seconds with a circle. Ask Stig.