An “Axle 31 Spline L/Bearing 32″” is a heavy-duty axle shaft typically used for custom or performance-oriented rear-end assemblies. This part is most commonly associated with a Ford 9-inch differential, a popular upgrade for high-horsepower vehicles.
Specifications
Axle: A solid shaft that transmits power from the differential to the wheel. This type is generally made from a strong, heat-treated steel alloy for durability.
31 Spline: Refers to the number of teeth on the end of the axle that engages with the differential. A higher spline count indicates a stronger axle. 31-spline axles are a common performance upgrade for Ford 9-inch rear ends.
L/Bearing: This abbreviation often means “large bearing.” It refers to the size of the bearing used to support the axle shaft near the wheel end. Ford 9-inch housings came with different bearing sizes, and the “large bearing” type is preferred for heavier loads and racing applications.
32″: The length of the axle, measured from the flange (the flat plate the wheel bolts to) to the end of the splines. Many performance axles are sold as “cut-to-fit” kits in longer lengths, like 32″, allowing for custom fabrication of rear ends to specific widths.
High-performance vehicles: Popular in muscle cars, hot rods, and drag racers due to the strength of the Ford 9-inch differential and the increased durability of a 31-spline axle.
Custom builds: Used for building custom-width rear-ends, as the axle length can be shortened to fit a specific chassis.
Heavy-duty street and track use: The combination of 31 splines and a large bearing is well-suited for vehicles with significantly more horsepower and torque than stock.