Joerg Lorenz said:
Yes they are: Below 8°C summer rubber gets very hard and has no grip
anymore. Snow Tyres are not only a question of snow, they are much
better in wet conditions and low temps.
Gee, that is 46°F. It gets colder than that in the American West at
night on the hottest days of summer. In fact in Hell's Canyon, between
Oregon and Idaho, I saw it get up to nearly 120°F (49°C) in the day and
our water bags froze solid at night. That is not unusual in the "big
sky" country. So I guess you wouldn't use summer tires at all here. We
do and we don't have any problems. Maybe our tires are a little more
accommodating that yours. Try some American "summer" tires, they do
have grip below 8°C. If they didn't we couldn't drive to the top of
Pike's Peak (14,110 feet) or to the top of Mauna Kea (13,796 feet)
without sliding off the roads that don't have guard rails. So our
summer tires must have some grip, in fact they have a lot of grip below
8°C. By the way if you do drive to the top of Pike's Peak or Mauna
Kea, take a coat. It is unbelievably cold up there on the hottest days
of summer and the wind almost blows you over. For example on July 12,
2006, on Mauna Kea in Hawaii, the temperature was 2C and winds were 40
mph. Pikes Peak it is even colder.