Some trailer manufacturers, such as LOADRITE & EZ-LOADER, use a ‘short hub’ on their 1” & 1-1/16” straight axles. Hub length or bearing distance should also be considered. Be sure to check both the inner and outer bearing measurements before ordering. If the number is not available, the most accurate way to measure the bearing I.D. Most bearings are stamped with a reference number that can be used to easily identify its inside diameter (see chart in our wheel bearing section). The second specification to determine is the Inner and Outer bearing size. To correctly measure the bolt circle of a hub, measure from the center of the hub to the center of a stud and multiple that measurement by two. Cargo and utility trailers with 5 lug hubs are commonly found with a 5” bolt circle. Most 4 lug hubs have a 4” bolt circle and most 5 lug boat trailer hubs have a 4-1/2” bolt circle diameter. The first specification to determine is the number of studs/bolts and the ‘bolt circle’ diameter. Whether you are replacing your entire hub or re-building the old one, it is very important to use the proper size replacement parts. Trailer Parts Superstore® carries a wide selection of high quality cast iron trailer hubs in SAE and Metric sizes.
