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Should you fit all-season tyres year-round, rather than switch from summer to winter designs? Our test reveals all.

Many drivers believe all-season tyres are the perfect solution for the UK’s erratic weather. They can cope with the odd few days of snow, work well when it’s cold and wet, and are less of a compromise in the dry than a full winter design.

That’s the theory; is it the reality? To find out, we put leading all-season tyres to the test – including, for the first time, the product that flies in the face of current thinking. Michelin calls its CrossClimate “a summer tyre with winter capability”, but it’s what it submitted for this all-season test, and it bucks the trend of all-season tyres that are hard to separate from winter rubber. As we saw in our winter tyre test, our all-season comparison tyre would have finished second. We’ve also included a temptingly priced Chinese budget option to see how it stacks up.

We moved up to the biggest-selling 17-inch size (225/45R17) for this test, to see how the tyres fared in a larger design. With the aid of Hankook we headed to Ivalo, Finland, for the snow tests at the independent Test World facility. Cold and wet, plus dry, tests were done with the help of Continental at its Contidrom facility near Hanover, Germany. We’ve also included our test-winning summer and winter tyres in this size to see how they fare in comparison.

So are all-season tyres the way to go for UK drivers? We find out.

This year we moved up to the big-selling 225/45R17 size for our all-season tyre test. The products we assessed are listed below, with their tyre label ratings for fuel economy (FE), wet grip (WG) and noise (N). The first two are rated from A-G, with A the best. Noise (in decibels) is measured as the car drives by. The lower the figure the better.

We’ve also given their speed and weight ratings – essential for getting the right tyre for your car. These range from H (up to 130mph) to Y (up to 186mph).

Hankook Kinergy 4S – Ratings: 94 V (FE) E (WG) C (N) 72

Nokian Weatherproof – Ratings: 94 V (FE) C (WG) A (N) 69

Star Performer Winter SPTS AS – Ratings: 94 V (FE) E (WG) C (N) 71

Vredestein Quatrac 5 – Ratings: 94 Y (FE) C (WG) C (N) 70

Winter tyre: Goodyear UltraGrip Performance Gen-1 – Ratings: 91 H (FE) C (WG) B (N) 70

Summer tyre: Continental ContiSportContact 5 –Ratings: 94 Y (FE) E (WG) A (N) 72

We’ve changed the way we find a winning all-season tyre to better reflect the kind of conditions they’re used in. Where before our results were equally split three ways between snow tests, wet road tests and dry road and other tests, for 2016 snow tests account for just 10 per cent of our scores. This is because most all-season tyres will spend precious little time on the white stuff and much longer in the dry and wet.

As before we assessed them in a range of tests, as well as on price, and the top performer in each individual category got a score of 100 per cent, with the rest rated relative to this. We added up these percentage scores to get a winner.

We weight each individual assessment to ensure it counts the same towards the overall snow, wet road or dry road result. So a test with a big margin between best and worst tyres, like aquaplaning, counts for less than one where there’s a small performance gap, like dry handling. The exception is price; this has a minor influence as tyres should primarily be bought on performance.

Snow is one of the main reasons drivers change tyres for winter. The performance gap between standard ‘summer’ rubber and a winter tyre is huge, as is the safety margin. We often struggle to even get to the tests on summer tyres in the snow.

Four elements of snow driving are tested to assess grip on the white stuff, and first is starting and stopping. Traction is rated on level stretches of graded snow, combined with braking. We get the car moving, then shift to second as early as possible before accelerating hard. GPS measures how long it takes to cover 25-50kph (16-31mph).

As soon as the car tops 50kph, we hit the brakes, triggering the ABS. The system measures the distance taken to slow from 50-5kph (31-3mph). The test is repeated eight times and an average taken. Our remaining tests measure lateral grip. On the circle we pick a line close to the centre, then accelerate until it can no longer be kept. We ease off the throttle to the point where we can hold that line, and repeat several times, taking an average of lap times.

Lap times are also at the heart of the handling test, but this time around one of Test World’s fast, flowing tracks. With all driver aids off, the 1,300m track is a real challenge for driver and tyre, combining quick sweeps with tight hairpins and fast changes of direction. The snow is graded between each run to ensure consistent conditions and we use an average of lap times to get a result.

While the threat of snow may push drivers to consider switching from summer tyres, all-season designs are also superior in the wet when temperatures drop. Around seven degrees Centigrade is the point where one type takes over from the other and our tests were done at or just below this level.

The circle, handling and braking tests are temperature sensitive; they rely more on the compound than aquaplaning, where tread is key. For our braking test – one of the few not done by Auto Express drivers – an adapted Golf was hooked up to the Contidrom’s rail system to ensure the same strip of tarmac is used for every attempt. The system measures the distance taken to stop from 50mph and an average of several runs is used for the result.

Not surprisingly, the circle test technique is the same as on snow, but the forces are higher and the track tighter. Around eight laps are done to get an average. From there we head to the winding handling track, which mixes fast direction changes with hairpins and sweeping turns, allowing us to lean on the tyre for longer periods. Lap times can be monitored in the car to ensure consistency. Again, we take an average of lap times.

Yet while the water is shallow in these tests, the aquaplaning assessments rate
the tyres in deeper water. These are done in a straight line and on a curve when those all-important tread channels are distorted.

The rail is used for the former, with one wheel in water. The car is accelerated hard and sensors measure when the wheel in the water is spinning 15 per cent faster than the one in the dry. This is the industry-accepted point at which control is lost. Several runs are taken and an average used.

For the curved test the car is driven around a tarmac circle with one flooded section. A g-meter measures the lateral forces at the increasing speeds. The car laps faster until all grip is lost; the higher the speed the better.

While we’d expect an all-season tyre to have the advantage on snow and in the wet and cold, summer tyres reclaim the edge in the dry, when those multiple grooves and slender sipes flex and move. But how much is the compromise? We did a series of stops from around 65mph and measured the distance taken to come to a halt from 62mph. As always an average of several runs was used.

The handling track also revealed any compromise needed when you switch tyres. Long sweeps and fast changes of direction really stretch the soft all-season designs. Our result was based on an average of lap times.

Cabin noise was measured when coasting from 50mph over smooth and rough tarmac, plus concrete slabs. We took an average decibel reading on each surface to get a final result. Rolling resistance is used to calculate what each tyre will cost you at the pumps. Our test, done to industry standards, measures the power needed to turn a loaded tyre. It’s similar to the difference between pedalling a bike with fully inflated tyres and one where the pressure has been reduced by 20psi. A one per cent change in fuel consumption requires a five per cent difference in rolling resistance.

Prices are taken from test winning online tyre retailer Black Circles. The fully fitted figures are what it advertised at the time of writing or, for tyres it didn’t stock, what it would charge if they were part of its range.