How to Determine the Correct Replacement Hubs for a Boat Trailer

Question:

I am having trouble deciding on which wheel hubs to get for my boat trailer.

asked by: Jason

Expert Reply:

To determine which hubs would be best for your boat trailer there are a few things you will need to look at; the axle capacity on your boat trailer, the inner bearing number, outer bearing number, grease seal number, the bolt pattern of your wheels, and whether or not your trailer has brakes.

If you do not know what your axle capacity is you can find it located on the axle itself. It is usually located towards the middle and will typically be stamped into the axle.

The bearing and grease numbers are to ensure that the hub fits the spindle that you have. If you take off your current hub you should be able to find the numbers stamped onto those pieces somewhere. Should you not be able to locate those numbers you can measure the parts B, C, and D of your spindle (see attached picture) with a Digital Caliper # PTW80157 to the 3rd decimal place, for example, 0.725 inches. Once we know the numbers or measurements we can then proceed on to which hubs are best for your boat trailer.

I recommend getting a Galvanized hub as the Galvanized finish helps to fight against rust and corrosion. This is extremely helpful for boat trailers since they are actually backed into the water. We can use a typical idler hub for an example. The part # AKIHUB-545-35-G-EZ-K is an idler hub that is rated for 3,500 lb axles. It has a Galvanized finish and uses a 5 on 4-1/2 inch bolt pattern for the wheels. It uses the following bearings and grease seal:

Inner bearing: # L68149 (1.378" inner diameter)
Outer bearing: # L44649 (1.063" inner diameter)
Grease Seal: # 58846 (1.719" inner diameter)

Now if you were to have brakes on your boat trailer then you will simply want to use part # 8-247-50UC3-EZ instead which has the exact same properties as the idler hub I just mentioned, only this is a hub and drum assembly for brakes.

If you are still unsure as to what is the correct hub to get for your boat trailer, just let me know what bearings and grease seal you have or what the measurements of your spindle are and I would be more than happy to assist you.