Leading British car magazine EVO has an unusual slant on the regular winter tyre test. Taking 2 identical Jaguar XFRs (5.0 litre Supercharged 500bhp V8!) and one snow covered Bedford Autodrome track, they fit one of the XFRs with over ?1200 worth of Pirelli SottoZeros, the new premium winter tyre from Pirelli while the second XFR keeps it's factory fitted high performance summer Dunlop Sport Maxx rubber.
The west circuit track conditions were variable with some corners covered in snow and slush and some merely wet. Once constant however was the ambient temperature at 3c which is well below the 7c where winter tyres start to come into their own. The EVO findings highlight that winter, or cold weather tyres really do offer a huge difference in cold and variable conditions.
After exiting the pits sideways the standard tyred XFR slid round the west circuit in a pedestrian 2:35 lap where as the XFR wearing the Pirelli Sottozeros was much more controllable, beating the summer tyres by over 30 seconds and posting a 2:04 lap. EVO even tried a four wheel drive EVO X FQ-330 on summer tyres to see if 4WD, opposed to rear wheel drive would save much time. It didn't, and the FQ330 slid around to a 2:29 lap, only 6 seconds faster than the standard XFR and 25 seconds slower than the winter tyred version.
As if 30 seconds a lap wasn't a big enough difference, braking tests revealed an even bigger gap. From just 60mph the summer tyres took a massive 782ft to stop, compared to the winter tyres 330ft! You could hit an awful lot in those 452 feet...
Buy this months EVO magazine, or follow the link here to read the full article. Next month EVO have promised to compare the performance of the 2 XFR's in day to day driving, we'll be sure to report on it!