How to Estimate Axle Weight Rating Based on Bearings Used in Hubs

Question:

I have a boat axle that Im trying to determine the weight capacity of the axle. It has under slung 5 leaf springs, UFP H-1377 hubs, its made out of 2inch X 3foot X 75inch long rectangular tubing with 2inch X 2inch square tubing upright weled on ends, 1 5/8inch diameter spindle welded to the 2inch sq. tubing. Total length of spindle is 7. 4 1/2inch from bottom of tubing to centerline of spindle. Spindle diameter is machined to fit bearings/seals for H-1377 hub.

asked by: Tommy

Expert Reply:

Thank you for the photo of your 2 x 2-inch square trailer axle, for which you are trying to determine rated weight capacity.

An older square boat trailer axle that uses the same bearing for inner and outer positions will typically be rated for 2000-lbs. An H-1377 hub uses a bearing of similar size to # L68149 and this bearing will often be found on axles rated from 2000- up to 3500-lbs at most.

If you can pull one of your hubs and find the part numbers for the inner and outer bearings that will allow getting you a more precise answer. You can use the linked page for hubs to select your inner and outer bearings. You will then see the hubs that use those bearings and based on the hub rating you can double that to get very close to the axle's own rating.

expert reply by: Adam R