Driveshaft Upgrades
In rear-wheel-drive and all-wheel-drive vehicles, the driveshaft transfers power from the transmission to the rear differential, spinning at engine speed under load. Factory steel driveshafts are robust but heavy, and their rotational mass contributes to drivetrain inertia that slows throttle response and absorbs energy during acceleration. Upgraded driveshafts address either strength concerns, weight reduction, or both. Chromoly steel driveshafts provide increased torsional strength for high-horsepower applications while maintaining reasonable weight. Carbon fiber driveshafts dramatically reduce rotating mass—often by 50% or more compared to steel—delivering improved throttle response, quicker acceleration, and reduced stress on transmission and differential components.
One-Piece vs Two-Piece Driveshaft Conversions
Many vehicles use two-piece driveshaft designs with a center support bearing to manage driveline length and reduce vibration. While effective for factory applications, the center support bearing adds complexity, potential failure points, and rotational mass. One-piece driveshaft conversions eliminate the center bearing by using a single, properly balanced shaft spanning the entire distance from transmission to differential. This conversion reduces weight, eliminates center bearing maintenance concerns, and often provides improved power transfer. However, one-piece conversions require proper engineering to avoid critical speed vibration issues at higher rpm.
Axle Strength and Material Selection
Axle shaft strength depends on material composition, heat treatment, and diameter. Factory axles typically use induction-hardened steel that provides adequate strength for stock applications but may twist or snap under significantly increased torque. Upgraded axle shafts use higher-grade alloy steels such as 4340 chromoly with improved heat treatment processes that increase both strength and fatigue resistance. Some performance applications benefit from increased axle diameter, though this may require hub modifications. For vehicles seeing regular drag racing, drifting, or high-horsepower street use, upgraded axles provide insurance against the sudden and complete loss of power transfer that occurs when a factory axle fails.
CV Joint and Boot Considerations
The CV joints at each end of an axle assembly are often the first components to fail under increased stress. Inner tripod joints and outer ball-type CV joints must accommodate both rotational power transfer and angular changes as the suspension moves. Upgraded CV axle assemblies typically feature joints with larger ball bearings, improved cage materials, and stronger internal components to handle higher torque loads. Heavy-duty CV boots resist the tearing and deterioration that can occur under aggressive use, protecting the joints from contamination and maintaining proper lubrication. Torn boots left unaddressed lead to rapid joint wear and eventual failure.
Symptoms of Failing Components
Clicking or popping sounds during turns often indicate worn outer CV joints, while clunking during acceleration or deceleration suggests inner joint or driveshaft issues. Vibration that increases with speed may point to driveshaft imbalance, worn center support bearings, or failing U-joints. Visible damage to CV boots, grease splatter around wheel areas, or play in axle assemblies all warrant immediate inspection. Addressing these symptoms before complete failure prevents being stranded and avoids potential damage to surrounding components.
Vehicle Applications
Our axle and driveshaft selection covers Subaru WRX, STI, BRZ, Forester XT, and Legacy GT; Honda Civic, Civic Type R, S2000, and Accord; Toyota GR86, Supra, 86, and MR2; Nissan 370Z, 350Z, GT-R, and 240SX; Mazda MX-5 Miata, RX-7, and RX-8; Mitsubishi Lancer Evolution; and additional performance platforms requiring drivetrain reinforcement.