Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course.
For example, a tire graded 150 would wear one and one-half (1- 1/2) times as well on the government course as a tire graded 100.
The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate.
See also:
Wear indicators
1) New tread
2) Worn tread
3) Tread wear indicator
Each tire incorporates a tread wear
indicator, which becomes visible when
the depth of the tread grooves decreases
to 0.063 in (1.6 mm). ...
For U.S.A.
The following information has been compiled according to Code of Federal Regulations “Title 49, Part 575”. ...
Efficient cooling after parking in direct sunlight
After parking in direct sunlight, drive with the windows open for a few minutes
to allow outside air to circulate into the heated interior. This results in quicker
cooling by the air conditioner. ...