Picking a winter winner
Each of our tyres was rated in a series of performance assessments
“Snow and wet tests each count for a third of the overall result; the other factors make up the remainder”
Snow braking
AVOIDING that dreaded moment when you hit the brakes on snow and the car barely slows is a key draw of winter tyres. Our test measures the distance taken to slow from 50-5kph (16-3mph), removing the variations ABS can create in the final few yards.
Snow traction
GETTING up hills is the second big factor in buying winter tyres. For this we got the car moving, changed to second below 25kph then accelerated as hard as possible. Our test measures the distance from 25-50kph (16-31mph). As in the braking test, the result is from an average of eight runs.
Snow circle
THIS is a crucial measurement of lateral grip on snow. We lined the car up on the inside edge of the 50-metre circle, applied a fixed amount of lock and accelerated until the line could no longer be held. The result is taken from an average of several laps.
Snow handling
THE 1,300-metre track at Ivalo is fast and flowing and really tests the tyres. There’s a mix of tightening turns and hairpins, and with all the electronic driver aids off it’s a real challenge. The track is graded between runs and the result is an average of lap times.
Wet braking
WITH the temperatures at Continental’s Contidrom facility in northern Germany around the point where you should switch between summer and winter tyres, we carried out a series of emergency stops in the wet from 80kph, measuring the distance they took, again from an average of runs.
Wet circle
YOU need a strong stomach for this test, which requires around 10 laps on the soaked 60-metre circle. Like the test on snow, we drove the car close to the inner kerb and accelerated until the nose pushed wide. The result came from an average of lap times.
Wet handling
AT the heart of this test are timed laps of the handling circuit which winds its way through trees and rocks inside the Contidrom’s banked oval. We kept the same braking points and lines, letting the time come from carrying more speed through turns and getting on the throttle earlier.
Straight aquaplaning
UNLIKE the other wet track tests, this is not temperature dependent as the major factor is tread rather than compound. The car is accelerated with one wheel in water. Wheel speeds are measured and we record the point at which one exceeds the other by 15 per cent. The higher the speed the better.
Curved aquaplaning
AS with the straight assessment, this test measures the speed when the tyre can no longer pump water from under the tread and rides up on to it. This is judged when the tread is distorted by cornering forces, with lateral grip measured as the car is driven through a flooded section at increasing speeds.
Dry handling
NOT the natural habitat for winter tyres; their soft, flexible treads prefer snow or rain. Our assessment is based on an average of lap times round the proving ground dry handling track’s flowing turns and direction changes.
Dry braking
WHILE drivers are most likely to exceed their tyres’ performance in the wet, this test is key when considering running winter rubber all year round. We measure the distance taken to stop from 100kph; the result is an average of runs, with exceptional results removed.
Rolling resistance
THIS is how a tyre’s fuel economy is rated. It measures the force required to turn a loaded tyre, and our test – carried out to industry standards – takes an average of two tyres. The greater the force required, the more fuel is used. A difference of around five per cent in rolling resistance equates to a one per cent change in fuel economy.
Cabin noise
WHILE the EU tyre labelling tests, driven by environmental concerns, focus on pass-by noise, we concentrate on levels in the cabin – vital for many drivers. We measured sound levels as the car coasted down from 50mph over three surfaces: smooth and rough tarmac, plus concrete slabs. An average from each one made up the final result.
Price
THIS plays a minor role in our overall result as tyres should be bought on performance, not price. Winner of our Issue 1,424 online tyre retailer test, Black Circles, provided the fully fitted prices; these are what it charged at the time of writing or what the tyre would cost if it was part of the company’s range.