Which of the following is true regarding timing belt drive systems?

The statement that timing belt drive systems are positive drive systems is accurate. A positive drive system ensures that the drive belt does not slip relative to the pulleys that it drives, maintaining a consistent and precise connection. This quality is essential in applications where timing and synchronization between components are critical, such as in engines or machinery where specific operations must occur in a defined order. The teeth on a timing belt fit into corresponding grooves on the pulleys, which prevents slippage and ensures that the rotation of the pulleys is accurately transferred to the driven components.

In contrast, flexible drive systems typically allow for some degree of slippage or flexibility in the connection, which is not a characteristic of timing belts. Timing belts also aren't prone to slipping under load, which differentiates them from more traditional belt systems like v-belts that can slip. Additionally, timing belts usually do not require frequent lubrication because they can operate effectively in a dry environment, further supporting the accuracy of the statement about their positive drive nature.