Which of the following is NOT an indication that a V-belt drive needs to be replaced?

A worn top surface of the belt is actually an indication that a V-belt drive may need replacement. When the top surface of a V-belt shows signs of wear, it means that the belt has lost its effectiveness and may not grip the driven pulleys properly, potentially leading to slippage or failure in transmitting power efficiently.

The other options highlight clear signs of deterioration that directly affect the performance of the V-belt. Cracks or fraying indicate serious damage and can lead to complete failure of the belt, while significant glazing, which refers to a shiny, smooth surface caused by overheating or excessive wear, shows that the belt is no longer effective in providing the necessary traction. Discoloration from use, depending on its severity, can also imply that the belt has been subjected to conditions beyond its operational limits. These factors combined suggest that the belt's integrity is compromised, necessitating a replacement.