How much difference can winter tyres make to your car’s performance and safety?
In snowy conditions, choosing between winter and summer tyres is like choosing between crampons and slippers, but plenty of British winters pass with barely a flake touching the ground. So it’s understandable that most of us are reluctant to fork out for winter tyres.
Yet tyre makers claim there are benefits when temperatures dip below 7degC, especially when it’s wet. In other words, the conditions you’ll typically find during a British winter. Are we missing a trick?
To see for ourselves, we’ve come to Pirelli’s Vizzola test track in Northern Italy. The temperature is hovering at a few degrees above zero while sprinklers keep the surface greasily wet. It’s here that we’ll compare winter and summer tyres’ performance during 0-62mph standing starts, braking tests and full lap times.
But, there’s a twist: we’re equipping our BMW 435i with 18-inch Pirelli Sottozero 3 winter tyres and pitching it head-to-head against an M3 on its factory-fit 19-inch Michelin Pilot Sports.
The 4.0-litre V8 M3 has 112bhp on the 3.0-litre turbocharged 435i, as well as uprated brakes and suspension, so it should monster the 435i. But can the 435i’s Sottozeroes overhaul the M3’s performance advantage? Time to find out…
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0-62MPH STANDING START
The official stats say that in perfect conditions our M3, with its dual-clutch transmission, should blitz the 0-62mph dash in 4.6sec. The manual 435i lags behind with 5.4sec.
Lined up side-by-side on the sodden racetrack, I hold the 435i’s revs at 3000rpm, selecting Sport Plus mode to minimise traction-control interference; Pirelli’s test driver holds his foot over the M3’s accelerator, leaving the traction control on to quell the inevitable flailing. 3-2-1…Go! I release the clutch smartly and the Sottozeroes claw at the surface. There’s moderate wheelspin, but still the rear tyres find purchase and drive us forwards.
The M3 bogs on the line, its traction control limiting power due to the sodden conditions, and by the time it’s found traction I’ve already pulled several car lengths clear. Into second and the 435i puts all of its power down with zero slip; the M3 still scrabbles intermittently, but it’s starting to gain. Ultimately, though, there’s nothing it can do in the time available, and I cross the line two car lengths ahead.
It’s 6.3sec to the 435i and 6.8sec to the M3 – the M3’s eight tenths advantage tumbles to a half-second deficit. We repeat the experiment, switching off the M3’s traction control, but nothing can get it back on terms with what should be a slower car.
>> Check CAR Online tomorrow for Part Two!