How do I measure my boat trailer bearings and races for replacement?

Measuring your boat trailer bearings and races correctly is essential for finding the right replacements. Trailer bearings come in many sizes, and even small differences can affect fit, performance, and safety. Luckily, measuring is simple if you know where to look and what tools to use.

The most common bearing sizes found on Venture boat trailers are:

• 1 1/16″ (Bearing: L44649/Race: L44610)
• 1 3/8″ (Bearing: L68149/Race: L68111)
• 1 1/4″ (Bearing: 15123/Race: 15245)
• 1 3/4″ (Bearing: 25580/Race: 25520)

Steps to Measure Boat Trailer Bearings

1. Remove the Hub
   • Safely jack up the trailer, remove the wheel and hub, then take out the bearings and races.
2. Clean the Parts
   • Wipe away all grease so you can clearly see numbers or measure accurately.
3. Check for Part Numbers
   • Most bearings and races have stamped reference numbers (e.g., L44649, L68149).
     If the numbers are legible, you can use them to order exact replacements.
4. Measure with a Caliper
   • If numbers are worn off, use a digital or dial caliper for precise measurement.
   • For Bearings: Measure the inside diameter (ID) of the bearing — this matches your spindle size.
   • For Races: Measure the outside diameter (OD) of the race — this matches the hub bore.
5. Confirm by Spindle Measurement
   • You can also measure the spindle where the bearing rides to confirm the ID.

Common Measurements You’ll Need

• Inner bearing ID (fits spindle)
• Outer bearing ID (fits spindle)
• Race OD (fits inside hub)
• Seal size (to prevent grease and water intrusion)

Tips for Accurate Replacement

• Always replace bearings and races as a matched set.
• Use marine-grade grease when reinstalling.
• If you tow in saltwater, consider stainless steel or coated bearing options.
• When in doubt, take your old bearings and races to a trailer parts supplier for matching.