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How to Find the Correct Trailer Wheel Bearings

Choosing the correct trailer wheel bearings is critical for safety, reliability, and long-term performance. Whether you’re servicing a box trailer, boat trailer, caravan, or camper, using the wrong bearings can lead to overheating, rapid wear, or even wheel failure.

This guide explains:

  • How to identify your trailer bearings correctly

  • How to read bearing numbers

  • The difference between bearing cone vs cup

  • Common bearing configurations used on Australian trailers

Why Correct Trailer Bearings Matter

Trailer wheel bearings:

  • Carry the full load of your trailer

  • Allow smooth wheel rotation

  • Prevent heat build-up in hubs

Incorrect or worn bearings can cause:

  • Excessive heat

  • Wheel wobble or noise

  • Hub, spindle, or axle damage

Correct identification is essential.

The Most Accurate Method: Remove & Read the Bearing Numbers

The only guaranteed way to identify trailer bearings is to physically remove them and read the stamped numbers.


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What You’ll Need

  • Jack & wheel brace

  • Pliers or screwdriver (for grease cap)

  • Rag or paper towel

Step 1: Remove the Wheel & Hub

  1. Jack up the trailer and remove the wheel

  2. Pry off the grease cap

  3. Remove split pin and castle nut

  4. Slide the hub off the axle

You’ll now see:

  • Outer bearing

  • Inner bearing

  • Seal (pressed into the hub)

Step 2: Locate the Bearing Numbers

  • The bearing number is usually stamped on the cone (roller bearing)

  • Clean grease off if needed

  • Write the number down exactly as shown

Common examples:

  • LM68149/10

  • 25580/20

  • 30210J

How to Read Trailer Bearing Numbers

Bearing numbers identify the exact size and type of bearing — not just the brand.

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Example Explained: LM68149/10

  • LM68149 = Bearing cone (roller bearing)

  • /10 = Matching cup (race)

These two parts form a matched set and must always be replaced together.

Why the Suffix Matters

Suffixes like:

  • /10

  • /11

  • /20

  • /245

Indicate differences in the bearing cup (width, chamfer, or standard).

⚠️ 68149/10 and 68149/11 are not interchangeable.

Visual Guide: Bearing Cone vs Bearing Cup (Race)

A trailer wheel bearing consists of two matching parts.

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Bearing Cone

  • Contains the rollers

  • Slides onto the axle

  • Usually has the bearing number stamped on it

Bearing Cup (Race)

  • Smooth outer ring

  • Pressed into the hub

  • Does not rotate

👉 Bearings must always be replaced as a cone + cup pair.

Common Trailer Bearing Configurations (Australia)

The table below shows commonly used bearing combinations found on Australian trailers, including setups used by manufacturers such as AL-KO, Dexter, Trojan, and Vehicle Components.

⚠️ This table is a reference only. Always confirm bearing numbers physically.

Bearing Configuration Table

Configuration Inner Bearing Outer Bearing
LM 0.75t – Holden 67048/10 11949/10
SL 1.45t – Ford / Slimline 68149/10 12749/10
PLL 1.6t – Parallel 68149/10 68149/10
AU 2.25t – AL-KO 2T 30210J 15123/245
AU 3.0t – AL-KO 3T 30210J 29749/10
DEX 3500LB – Dexter 3500 lb 68149/11 44649/10
DEX 6000LB – Dexter 6000 lb 25580/20 15123/245

Important Notes on Common Configurations

Parallel Bearings

  • Same bearing inner and outer

  • Common on 45 mm square axles

  • Often paired with 6-stud hubs

  • ❗ Not the same as Ford bearings

AL-KO 2T & 3T Bearings

  • Found on genuine AL-KO braked axles

  • Larger taper roller bearings

  • Inner and outer bearings are different sizes

  • Correct seal selection is critical

Dexter Bearings

  • Common on imported or US-style axles

  • Often mistaken for standard sets

  • Not interchangeable with Ford or Holden

Don’t Forget the Seal

Replacing bearings without replacing the seal is a common mistake.

Always identify:

  • Seal inner diameter

  • Seal outer diameter

  • Seal width

A worn seal can allow grease loss and water ingress, destroying new bearings.

Boat Trailer Tip 🌊

Boat trailers face:

  • Water exposure

  • Salt corrosion

  • Frequent submersion

If bearings show rust, pitting, or blue heat marks — replace them immediately and use marine-grade grease.

Final Checklist Before Ordering

Before purchasing bearings, confirm:
✅ Inner bearing number
✅ Outer bearing number
✅ Matching cup numbers
✅ Seal size
✅ Braked or unbraked hub

Final Word

Trailer bearing identification should never be a guess. Bearing numbers stamped on the bearing itself are the only reliable method — not trailer size, axle rating, or stud pattern.

When in doubt:

  • Remove the bearing

  • Read the number

  • Confirm before ordering

It’s the safest and cheapest way to keep your trailer rolling reliably.

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