What is the 3% rule for tires?
The 3% rule states that when replacing tires, the new tire’s diameter should not differ from the original by more than 3%. This guideline helps maintain proper vehicle performance, safety system functionality, and speedometer accuracy. The performance of tyres deteriorates the more worn they become. In fact the difference in stopping distance between tyres with 4mm or tread and tyres with the legal minimum of 1. That is why it is recommended that they are changed once tread levels reach 3mm or less.This index is between 60 and 620, with 100 as the reference standard. For example, a tire with a treadware index of 50 will wear 2 times faster than a normal tire whereas a tire with a treadwear index of 420 will wear 4. REMEMBER: The higher the treadware index, the longer the life of the tire.
What does C mean in tire size?
The C-Type tire, on the other hand, is specifically meant as a commercial-rated tire, with a higher load rating for a given size than many LT tires. These C-Type tires will show the letter “C” immediately after the wheel diameter in the tire code. This new European tyre label applies to passenger car tyres (C1), light truck tyres (C2) and heavy truck tyres (C3).