Carbon Fiber Driveshaft Pros and Cons

Carbon fiber driveshafts are increasingly being employed in automotive, commercial, defense, industrial, and marine applications. Due to their unique combination of attributes, they are frequently used in the most demanding and specialized industries.

Independent research by a reputable automotive publication revealed that simply switching from a normal steel driveshaft to a carbon-fiber driveshaft enhanced rear-wheel horsepower by more than 5%. This is primarily owing to the carbon fiber driveshaft's lower rotational mass. A lightweight carbon fiber driveshaft facilitates the transfer of engine power to the wheels.

Vibration in the driveline is a typical issue that can impede RPM. Metal driveshafts are susceptible to harmonic whip in racing conditions, reducing the engine's useful RPM and requiring it to run well below redline in each gear. The development of a carbon fiber driveshaft increased the engine's usable speed by 1000 RPM, allowing it to operate at its power peak. Since their introduction in 1987, carbon fiber driveshafts have become popular among racers across a wide range of disciplines.

When torque is applied, all drive shafts twist slightly. The resistance to this twist is quantified as a torsional spring rate. The torsional spring rate of carbon fiber (composite) drive shafts is lower than that of aluminum and half that of steel. Reduced driveline shock and load on other drivetrain components, as well as better traction, are all advantages of a reduced spring rate.

The constant twist caused by torque eventually leads all metal shafts to twist somehow. After a period of time, the shaft ends become permanently out of phase by several degrees, and vibration begins to deteriorate components. Carbon fiber driveshaft, on the other hand, have an almost perfect "elastic memory," which means they cannot fail due to persistent twisting.

All drive shafts begin to whip as RPM increases. This bending of the shaft causes lateral run out and vibration when it occurs at a certain "critical speed," which is specific to each type of driveshaft. This vibration is the main cause of drivetrain breakdown from the transmission to the rear end. Carbon fiber shafts have a substantially greater "critical speed" than steel or aluminium shafts of equal size. Outstanding harmonic damping, combined with strong lateral stiffness and low density, completely eliminates shaft whip vibration concerns.

Carbon fiber driveshafts are designed for strength and torque transfer, however, they can be damaged with a powerful side hit. When a u-joint or yoke breaks, the carbon fiber composite starts to break down when it comes into contact with the chassis. Instead of ripping the driver and vehicle apart as the composite breaks down, the shaft just becomes a mass of loose carbon fibers.

Carbon Fiber Driveshaft Pros 

• The use of a carbon-fiber driveshaft raised the engine's useful speed by 1000 RPM, allowing it to function at its maximum power.
• Carbon fiber (composite) driveshafts have a lower torsional spring rate than aluminium and half that of steel.
• Reduced spring rate benefits include reduced driveline shock and load on other drivetrain components, as well as improved traction.
• Because of the continual twist generated by torque, all-metal shafts eventually twist in some way.
• Carbon fiber driveshaft, on the other hand, have near-perfect "elastic memory," which means they won't break down due to repeated twisting.
• Carbon fiber shafts have a far higher "critical speed" than steel or aluminium shafts of the same diameter.
• Shaft whip vibration can be completely eliminated thanks to excellent harmonic damping, robust lateral stiffness, and low density.

Carbon Fiber Driveshaft Cons

• With only a single scratch or ding, it's no longer a component but a broom.
• While it may be tempting to choose for the best, a carbon fiber drivetrain is not for everyone.
• Expensive