Telegraph journalist Chris Knapman visits the Porsche expertise Centre to place winter and summer tyres to the check
This is exactly matters wherever the owner of a four-wheel-drive SUV ought to be feeling content.
Sat at rock bottom of a hill, its surface lustrous with ice, you push the accelerator to the ground and wait all of these pricey differentials to try and do their job.
You creep forward, however not as you would possibly suppose, for whereas the speedo is mounting it's wheel speed and not road speed that you’re gaining. The handwheel has gone light-weight in your hands and has very little influence on your direction of travel, inflicting panic as your two-tonne automobile begins to wander toward the verge. You stop before you hit something, however currently you’re stuck. And you’re want you had invested with in an exceedingly set of these winter tyres that everyone keeps talking regarding.
In fact, the right term is cold-weather tyres, however “winter tyres” has become the vernacular thus that’s what we’ll continue. And to ascertain specifically however smart they're we tend to spent daily at the Porsche expertise Centre at Silverstone, that with great care happens to possess its own "Ice Hill" snuggled between the high-speed check tracks. This seven per cent slope options a low-friction surface and 2 computer-controlled water jets to simulate the sort of conditions that for the last 2 years have sent British roads into a state of chaos.
Time to place into observe what we tend to preach.
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A two-wheeled drive automobile on winter tyres is healthier than a four-wheel-drive automobile on summer tyres...
Having around (and it had been an in depth thing) managed to zag zig our thanks to the highest of the Ice Hill in an exceedingly four-wheel-drive Cayenne on summer tyres, we tend to area unit reaching to strive one thing slightly completely different.
Climbing down from the large SUV I land within the seat of a rear-wheel drive, superior Porsche Boxster and come to rock bottom of the Ice Hill. In theory the Boxster shouldn’t stand an opportunity here, however as I slot the gearlever into drive and meet the throttle it begins to maneuver. Be too formidable with the ability and therefore the rear wheels can still spin, however with a trifle of restraint it ascends hill with ease, its steering crisp and controlled. The distinction, of course, is that it’s carrying winter tyres.
...but a four-wheel-drive automobile with winter tyres is healthier once more
With that expertise beneath our belt it’s no surprise to seek out that swapping to our third and final automobile, a four-wheel-drive Cayenne on winter tyres, we tend to build it to the highest of hill with ease. In fact, such is that the grip on supply that you just ought to be quite aggressive with the controls for love or money dramatic to happen.
It’s an analogous story once we place the cars through a slalom, now motion down the Ice Hill. On summer tyres the Cayenne doesn’t even build the primary flip, understeering dispiritedly before threatening to travel into a large spin. strive an equivalent within the Boxster on cold-weather tyres and you continue to have to be compelled to work the steering, applying 0.5 a flip of opposite lock as you guide the automobile between the obstacles, however the distinction is that as presently as you straighten the handwheel the tyres regain grip.
Again tho', it’s the Cayenne on winter tyres that puts within the strongest performance, weaving through the slalom while not a retardant. And it’s not simply that you just will see and feel the grip, however you'll hear it too, the tyres thrumming with happiness as they bite into the surface.
Four-wheel-drive would possibly facilitate to you get down, however it’s of no use once you’re attempting to prevent
Our driver within the Cayenne on summer tyres might need had a torrid time going to the highest of hill, however currently there he will continue on his method. Before he is aware of it he's heading back downhill once more at a gradual 24mph once, within the distance, he sees a lorry has jack-knifed and is obstructing the road. He brakes as onerous as he will, however whereas he will feel the ABS system pulsing through the pedal the automobile sails forward, its speed barely decreasing because the tyres glide across the paved surface. thereon same seven per cent Ice Hill it takes fifty five metres to come back to a whole stop. From the driver’s seat it's, quite candidly, terrifying.
Behind, the Cayenne with winter tyres is motion at precisely the same speed. recognizing the lorry at an equivalent purpose it too performs Associate in Nursing emergency stop. once more the ABS pulses, however now the nose dives because the tyres grip, and therefore the automobile involves a halt in mere thirty metres.
In fact, thus effective area unit the tyres that it takes the Cayenne simply 5 metres additional to prevent than the a lot of lighter Boxster.
What makes winter tyres thus effective?
First, the tread pattern. Winter tyres feature additional “sipes” (or grooves) among the tread blocks ( اسپری پنچرگیری لاستیک ) to supply traction and stability. In snow these sipes truly fill with snow, that then grips to the snow on the road (imagine rolling a snowball) to supply traction. there'll even be a better groove to rubber magnitude relation to assist clear water and cut back aquaplaning.
Winter tyres even have a distinct compound, with a high-silica content which means that they keep softer, additional pliable and so supply additional grip at low temperatures than summer tyres.
When finding out new rubber, SUV drivers may also encounter Mud and Snow tyres, that area unit outlined by TyreSafe as those “whose tread and structure area unit designed to present higher handling than traditional tyres in slush and contemporary or melting snow”. However, there are not any rules stating that such tyres ought to additionally feature a winter-specific compound, that is thus essential to performance in cold conditions. to confirm that the tyres area unit winter-specific, search for a snowflake or snow-topped mountain image on the sidewall.
When ought to I work winter tyres and the way a lot of can they cost?
Due to their compound, winter tyres inherit their own as presently because the temperature drops below seven degrees C. that's to mention, from late October till March you’ll have the benefit of superior acceleration, braking and handling – and so safety – if your automobile has winter tyres fitted. That applies on dry, clear roads, and their advantage over summer tyres solely will increase in rain, snow and ice.
As for value, it depends on the automobile you drive and therefore the tyre you decide on to shop for. For the Cayenne we’ve been testing, Associate in Nursing approved wheel and winter tyre package from Porsche prices from £1,600, and for the Boxster from £1,800. Audi sells wheel and tyre packages from £799 (or tyres solely from a really affordable £325), and nowadays is throwing in an exceedingly year’s wayside help if you purchase wheels and tyres.
The other choice is to supply your own winter rubber, that you’ll be paying regarding £350 and £40-60 for fitting, counting on that tyres you decide on and wherever you are taking them to be fitted. For the latter, it’s well price phoning around for a number of quotes.
Remember too that the performance of a summer tyre can vary tremendously counting on what quantity you pay, and therefore the same applies to winter rubber.
Other concerns
- Last winter the Association of British Insurers revealed a winter tyre agreement, stating that insurers wouldn't charge a further premium if customers value more highly to work winter tyres. As such, there shouldn’t be any associated value with creating the swap, however it’s price a fast courtesy decision to let your underwriter recognize.
- It sounds obvious, however think about wherever you’re reaching to store your existing wheels and tyres. If you don’t have area reception then your main dealer might need area and be happy to store them. usually this can value regarding £10 a month, though some dealers might need special offers (Suzuki is presently charging customers £49.99 for a year).
- bear in mind that winter tyres should be fitted to all or any four wheels. solely fitting them to the driven wheels on a two-wheel-drive automobile can end in unbalanced handling and braking.
- If you already use winter tyres bear in mind to envision that they need adequate tread. The AA advises a minimum of 3mm for winter driving, and no but 2mm.
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