Why does a car shake over 60 mph?

A car may shake over 60 mph due to several factors, including unbalanced wheels, misaligned tires, or worn suspension components. Imbalanced wheels can cause vibrations that become more pronounced at higher speeds. Additionally, issues with the drivetrain, such as a damaged driveshaft or worn-out bearings, can also contribute to shaking. It's important to have these problems diagnosed and repaired to ensure safe driving.