For several years, there’s been efforts on the E-Type forum to reach out to Vredestein to better understand a generic Summer Tire warning posted by Tire Rack (which includes the 185R-16 Sprint Classic appropriate for XK Jaguars). During this period, Vredestein has been less than helpful, leading some on the E-Type forum to speculate a worst case scenario where even storing (not driving) a Sprint Classic at cold temperatures could permanently damage the tires.
Now it appears that Vredestein has provided reassurance that the Summer Rated Sprint Classics are not constructed of the problematic “R-Compound.” Thus, they may lose some of their warm-weather traction below 40 degrees, but the tires are perfectly safe, structurally, for cold temperature driving. Vredestein is apparently in the process of writing “bulletin” to this effect.
For additional details, see the recent Vredestein postings on the E-Type forum.
The general understanding here in Europe is that in winter it’s better to drive a “Winter tire”. Most of the recommendations state that when temperatures are dropping below 7 Celsius (or 44 F), winter tires are beginning to have an advantage over Summer tires. But there is no obligation to switch to winter tires. Only in countries where they have a lot of snow on the roads during winter time, the use of winter (or better snow) tires is mandatory and it’s forbidden to continue driving summer tires. But this is more because of the optimized “profile” of winter tires than the declining elasticity of the rubber of summer tires.
In the more moderate climates here in Europe (unfortunately also helped by “climate warming”) these “summer tires” are normally driven all year round, even when temperatures are dropping below zero Celsius for a few days or even a few weeks.
So we’re not surprised that Vredestein (originally a Dutch company) provided this answer.
I drove my Jaguar XK 140 with Michelin X radials summer tires, all year round, but have to add that I don’t drive when it snows (in particular because of the salt on the roads!). My XK 120 has the Vredestein Sprint Classic tires and I hope I will be able to drive it as soon as it’s ready, no matter the temperature outside…