P30L050-1610 L TIMING P30L050-1610 Classical Timing Pulleys and belts are used in the cases when the system requirements do not allow slippage. Timing pulleys resemble gears with rounded teeth and engage with a mating toothed belt. These H series of timing pulleys offer an advantage over chain drives by allowing higher operating speeds, high efficiency and free lubrication. The pulleys are straight bored for small sizes and TB Bushed for larger sizes.