Trailer Parts Superstore - How To Measure Trailer Axles (2024)

When selecting a trailer axle for your application remember to consider the following important specifications:

• LOAD CAPACITY: the load rating of the axle must support the maximum gross vehicle weight rating. For multiple axle trailers divide the GVW by the number of axles to determine the minimum load capacity of each axle.
• TRACK LENGTH: measure your axle track length by determining the distance between the center of one tire to the center of the other tire. A more precise measurement can be made by measuring the distance from one 'HUB FACE' to the other. The hub face is also known as the mounting surface where the wheel studs are located.
• SPRING CENTERS: measure the distance from the center of one spring to the center of the other.
  NOTE: not required for replacement torsion axles
• OVERALL LENGTH: measure the distance from the very end of an axle's spindle to the very end of the opposite spindle.
• AXLE STYLE: important when reusing old mounting hardware and also for proper tire clearance. Includes straight axles (round or square), drop axles with offset spindles, and torsion axles. Also consider spindle size when reusing existing hubs or drums.

HOW TO MEASURE A TRAILER AXLE:

MOUNTING A TRAILER AXLE:

CAMBER: Many trailer axles are cambered or 'road set' so there is a bow until weight is put on the axle. All cambered axles should be mounted with the center bow up.

SPRING MOUNTING: When replacing a trailer axle try to determine how it was previously mounted. Under slung mounts have the spring mounted below the axle and over slung mounts have the spring mounted on top. Round axles are shipped with un-mounted spring seats. Spring seats can be mounted over or under the axle (requires welding) at the desired location.

ROUND STRAIGHT TRAILER AXLE	ROUND TAPERED TRAILER AXLE
ROUND DROP TRAILER AXLE	SQUARE STRAIGHT TRAILER AXLE
SQUARE DROP TRAILER AXLE	TORSION TRAILER AXLE