How do you know what size is your boat trailer bearings?

[FishingRebel]

I want to go buy a bearing kit for my boat trailer.   It is for a 15.5 feet boat.   How do I know what size to get?

 

 

[RebelSS]

Make sure you get the bearing and race. I'd also suggest good ol' USA bearings like a Timken or such.  Trailer wheel bearings are specific to the spindle that is installed on the axle that's on your trailer.You'll need to jack up the trailer, remove the wheel, pop the grease cap off, remove the cotter pin and washer that secures the spindle nut, remove the spindle nut, and then you will be able to remove the hub from your trailer.Once the hub is off, you'll  be able to get the part numbers from the inner and outer bearings to determine the correct bearings for the spindles.