Technician A says that carbon fiber driveshafts need support bearings every 24 inches. Technician B says that carbon fiber and aluminum driveshafts reduce rotating mass and are more efficient than steel driveshafts. Which technician is correct?

Technician B is correct because both carbon fiber and aluminum driveshafts are designed to be lightweight, which significantly reduces the rotating mass compared to traditional steel driveshafts. This reduction in weight allows for greater efficiency since less energy is needed to accelerate the driveshaft, leading to improved performance, response times, and fuel economy in vehicles.

In contrast, the claim made by Technician A about the need for support bearings every 24 inches for carbon fiber driveshafts may not be universally applicable. The dependence on support bearings generally relates to the length of the driveshaft and the specific engineering of the vehicle rather than a fixed distance requirement. Driveshaft design and configuration depend on various factors such as the vehicle's torque requirements and chassis layout, which can vary widely from one application to another. Therefore, while it is important to consider support bearings in driveshaft design, Technician B's assertion regarding the efficiency and reduced mass of carbon fiber and aluminum is affirmed by the principles of materials science and performance engineering.