SUVs with four-wheel drive in particular need good winter tires. Because the very good traction of the four-wheel drive often belies the dangers when braking. In the test eight winter tires of the dimension 235/55 R 17.
Mirror-smooth, icy roads, snow-covered cars, deep snow on uncleared paths, driveways and parking lots – admittedly, these conditions have become relatively rare in the US. But there are regions where snow is still a part of everyday life in winter. And, of course, even if you’re a flatlander driving to the mountains for winter sports.
All-wheel drive needs good winter tires
The advantages are obvious: if all four wheels are driving the car, traction is improved by 50 percent in purely mathematical terms. This not only halves the acceleration time on slippery roads. Steep inclines or deep snow around a parking space are no longer daunting.
But all-wheel drive also has a downside: In addition to the higher costs due to the additional construction effort, higher consumption due to extra weight and greater friction, the risk of accidents can even increase. Or the accident may be more severe due to the effortlessly achieved higher speed. The keyword in this context is risk compensation. Put simply, the driver relies too much on the technology and simply does not realize how smooth it really is when starting off. This makes the right tires all the more important for all-wheel-drive cars as well.
Traction is better measured with two-wheel drive
Which winter tires in the 2017/2018 season are particularly well suited for an SUV such as the popular Ford Kuga or even the VW Tiguan?
However, to measure the acceleration capacity of a tire on a solid snow surface, the four-wheel drive is less suitable. A significant difference between good and less good tires can hardly be felt behind the steering wheel. That is why we carried out the traction measurement with two-wheel drive.
Even the basic version of the Ford Kuga with two-wheel drive, fitted with the right tires, is a very good winter car that doesn’t get stuck on every little incline. It usually only needs a little more start-up than the all-wheel drive version. However, a clear recommendation to buy one of the eight tires tested cannot yet be given after this measurement. The best and the weakest tire were separated by just around ten percent in the tractive force measurement.
Traction is not an issue, but lateral grip is.
When it comes to braking on snow, there are still no significant differences between the tires. Here, the brakes are always applied with four wheels, and all manufacturers now seem to have mastered the necessary formula, which is essentially: as many sipes as possible and a soft, grippy rubber compound. However, there are clearer differences on the handling course. Here, additional lateral control is required and the load change reactions make the tires’ job difficult. This again shows how quickly the limit can be reached with all-wheel drive, but after that it’s mainly the quality of the tires that determines whether the corner can still be taken.
Although the Kuga’s ESP sometimes seems overly cautious, with the skid protection switched off it is sometimes only possible to go even faster with a lot of effort and risk. Especially with the all-wheel drive it is not always clearly predictable whether the car wants to push over the front wheels to the exit of the bend or whether the rear suddenly swings out when the load changes. With the Conti and Dunlop tires, confidence in lateral control is at its highest, making the Kuga the easiest and fastest to drive around the handling course.
Less on the clock, but subjectively, the Nokian as well as Goodyear and Pirelli also feel good. You can’t go as fast with these in absolute terms, but reaching the grip limit is announced early and the Kuga remains easy to control even in the following slide phase. Hankook, Kumho and Cooper have some catching up to do in this respect. If you are too fast on the road, which can easily happen with the all-wheel drive, then the ridge between still getting a corner and taking off is much narrower and more difficult to control.
On dry roads, the winter tires do not decelerate very well
If the road is only wet, which is more the rule in winter in this country, then completely different qualities are required. Then a relatively stiff tread is needed for braking, and the rubber compound must be able to interlock with the asphalt rather than with snow. Dunlop and Goodyear have gained an advantage in this discipline with the latest generation of tires and can now outbrake Continental’s former flagship TS 850 P tire. Kumho and Pirelli have also done their homework and can now offer good results in the wet. The performance of the Nokian WR A4, on the other hand, is rather disappointing. In the SUV format one concentrated perhaps somewhat too much on other criteria, the lateral guidance on wet road is only satisfying and on the level of the test tires of Hankook and Cooper.
Aquaplaning is not really an issue with tread depths between eight and ten millimeters when new. Surprisingly, however, the Pirelli does exceedingly well here, although it is at the lower edge of the tread depth with 8.1 millimeters. However, the tread seems to drain water well due to its design.
The entire test field does not do quite as well in braking on dry roads. This is much better with summer tires. SUVs, winter tires and sporty driving on dry roads are therefore not a good match.
The conclusion: Even in a car with all-wheel drive, you should by no means skimp on winter tires, even if pure progress still seems assured. Being able to accelerate is one thing, but braking and cornering are another, much more important thing.
Auf diese Autos passen die getesteten Reifen:
- Audi Q3
- BMW X3 (E83)
- Ford Kuga
- Volvo XC70 ab 2007
- VW Tiguan