Should You Replace 4 Tires at Once or Just 2?

[DeLondon]

Whether to replace 4 tires at once or just 2 depends on economic cost and actual usage conditions. The decision should be based on tread wear indicators - those small raised blocks in the tire tread pattern. When the tread wears down to the level of these indicators, it means the tire has reached the end of its service life. At this point, the tire's friction performance, water drainage, pressure resistance, and collision resistance are significantly reduced, making it difficult to ensure safe and stable operation in emergencies, so replacement should be done as soon as possible. For normally used tires (without issues like uneven wear, cupping, damage, or bulges), replacement should be based on actual wear conditions. However, there's one principle: when replacing tires, it's best to replace both tires on the same axle simultaneously. On one hand, tires on the same axle usually wear at similar rates, so their replacement cycles won't differ much. On the other hand, replacing only one tire may affect vehicle stability and braking performance due to different friction coefficients between the two sides.