What is the 105% rule on tires?
The Rule of 105 says your rim’s external width must be at least 105% of your tire’s actual measured width. If the rim is narrower than the tire, airflow breaks apart and creates drag. If the rim is slightly wider, air stays attached and improves speed and stability. A commonly cited guideline is the 105% rule, where the rim should be at least 105% of the tire’s width to optimize airflow. Poor matching can create a “lightbulb” shape that catches wind and increases drag, even if the tire itself has low rolling resistance.
What is the 7 7 rule for tires?
The 7 7 rule for tires provides a simple temperature guideline for timing your seasonal tire changes. Install winter tires when daily temperatures drop to 7°C (45°F) or below for seven consecutive days. Remove them in spring after seven straight days above 7°C. Nonetheless, the recommended time to switch over to Winter Tires should be late September to early November.