These Sterling spools are machined from 4140 steel, splined, heat treated, and then finish turned on all locating surfaces for maximum precision and durability. Designed for Sterling 10.25 / 10.5 applications, these spools provide a fully locked differential solution for high-horsepower street, drag racing, and off-road builds.

Each spool comes standard with the factory 1.5” 35 spline axle pattern for direct compatibility with common Sterling rear end setups. The design ensures proper fitment and strength under extreme load conditions while delivering consistent, equal power transfer to both wheels.

Custom spline configurations are available upon request to support a wide range of axle and drivetrain combinations.

This item is proudly designed, engineered, and manufactured in house at IMS.