You need to replace a trailer wheel bearing. You pull the hub, look at the old bearing, and find a number stamped on it — or maybe you don't. Now what?
This page is the reference you'll bookmark. We've compiled the most common trailer wheel bearing sizes organized by axle weight rating, along with seal sizes, grease specs, and identification tips. Whether you're ordering parts or just figuring out what's in your hubs, this chart has you covered.
The bearings in your trailer hubs are determined by the axle's weight rating, not your trailer's total weight. A tandem axle trailer rated at 7,000 lbs GVWR uses two 3,500 lb axles — so you'd look at the 3,500 lb row below.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | L44649 | L44610 | 1.0625" | 1.9800" |
| Outer (front) | L44649 | L44610 | 1.0625" | 1.9800" |
Seal: 1.249" ID × 1.983" OD (Grease seal #10-19)
Spindle: 1" straight
Notes: Same bearing inner and outer. Common on small utility trailers, lightweight boat trailers, and jet ski trailers. The L44649/L44610 is one of the most widely available bearings — every auto parts store stocks them.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | L68149 | L68111 | 1.3775" | 2.3280" |
| Outer (front) | L44649 | L44610 | 1.0625" | 1.9800" |
Seal: 1.719" ID × 2.565" OD (Grease seal #10-36)
Spindle: 1-1/16" to 1-3/8" stepped (EZ Lube style common)
Notes: The most common trailer axle in America. Found on most single-axle utility trailers, mid-size boat trailers, and light cargo trailers. If you have a trailer and don't know the axle weight, there's a good chance it's a 3,500 lb with this bearing combination.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | 25580 | 25520 | 1.7500" | 3.2650" |
| Outer (front) | 15123 | 15245 | 1.2500" | 2.4410" |
Seal: 2.125" ID × 3.376" OD (Grease seal #10-60)
Spindle: 1-3/4" to 1-1/4" stepped
Notes: Common on car haulers, larger boat trailers, and medium-duty equipment trailers. The step up from 3,500 lb to 5,200 lb is significant — larger bearings, beefier spindles, and more grease capacity.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | 25580 | 25520 | 1.7500" | 3.2650" |
| Outer (front) | 15123 | 15245 | 1.2500" | 2.4410" |
Seal: 2.125" ID × 3.376" OD (Grease seal #10-60)
Spindle: 1-3/4" to 1-1/4" stepped
Notes: Same bearing combination as the 5,200 lb axle in most configurations. The 6,000 lb axle typically uses heavier springs and a beefier tube, but the spindle and bearings are often identical. Common on horse trailers, larger enclosed trailers, and heavy equipment haulers.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | 14125A | 14276 | 1.2500" | 2.7170" |
| Outer (front) | 25580 | 25520 | 1.7500" | 3.2650" |
Seal: 2.250" ID × 3.376" OD
Spindle: 2-1/4" to 1-3/4" stepped
Notes: Found on heavy tandem-axle trailers, large car haulers, and gooseneck flatbeds. Some 7,000 lb axles use different bearing configurations depending on the manufacturer — always verify by measuring your spindle or checking the existing bearing numbers.
| Position | Bearing Number | Race (Cup) Number | Inner Diameter | Outer Diameter |
|---|---|---|---|---|
| Inner (rear) | HM218248 | HM218210 | 3.5430" | 5.7870" |
| Outer (front) | 25580 | 25520 | 1.7500" | 3.2650" |
Seal: Varies by manufacturer — measure existing seal
Spindle: Varies — typically unitized hub or large stepped spindle
Notes: Heavy-duty territory. Found on large gooseneck trailers, heavy equipment haulers, and commercial-grade flatbeds. At this capacity, you may encounter unitized hub assemblies (non-serviceable bearings that are replaced as a unit) rather than traditional tapered roller bearings. Always verify the configuration before ordering parts.
Three ways to figure out what bearings your trailer uses, ranked from easiest to most involved:
Most trailer axles have a capacity sticker on the axle tube or on the trailer's VIN plate. Find the per-axle rating and match it to the chart above. This works about 80% of the time — the other 20% are non-standard or custom configurations.
If you've already pulled the hub, look at the bearing itself. The part number is stamped on the cone (the inner part with the rollers). It's usually on the small end face or the side of the cone. Common numbers you'll see:
The number on the bearing tells you exactly what to order for replacement — including the matching race.
If there's no sticker and no readable number on the bearing, measure the spindle diameter where the inner bearing sits (the larger step) and where the outer bearing sits (the smaller step). Match those measurements to standard spindle sizes:
| Inner Step | Outer Step | Typical Axle Rating |
|---|---|---|
| 1.000" | 1.000" | 2,000 lb |
| 1.375" | 1.0625" | 3,500 lb |
| 1.750" | 1.250" | 5,200-6,000 lb |
| 2.250" | 1.750" | 7,000 lb |
Use a caliper for accurate measurement — a tape measure isn't precise enough for bearing identification.
When you order replacement bearings, make sure you get the complete kit. Here's the shopping list for each hub:
Most trailer parts suppliers sell these as complete kits for $20-50 depending on the axle rating. Buying the kit is easier and cheaper than sourcing individual components.
Not all grease is created equal, and using the wrong type can damage your bearings.
| Application | Grease Type | NLGI Grade |
|---|---|---|
| Standard trailer (road use) | Lithium complex | #2 |
| Boat trailer (water exposure) | Marine-grade (lithium complex or aluminum complex) | #2 |
| High-temperature application | Synthetic or polyurea | #2 |
Approximate grease quantities by axle size:
| Axle Rating | Per Bearing (approx.) | Hub Cavity |
|---|---|---|
| 2,000 lb | 1-2 oz | 2-3 oz (1/3 full) |
| 3,500 lb | 2-3 oz | 3-4 oz (1/3 full) |
| 5,200-6,000 lb | 3-4 oz | 4-6 oz (1/3 full) |
| 7,000-8,000 lb | 4-6 oz | 6-8 oz (1/3 full) |
Bearing replacement and repacking follow different schedules:
Always replace bearings in sets (inner + outer on the same side), and always replace the races at the same time. A new bearing in an old, worn race will wear out rapidly.
If you maintain your own trailer, here's the tool list for a bearing repack or replacement:
Total investment for the tool set (if starting from scratch): $50-100. You'll use all of it again next year.
The charts and schedules above tell you when to service bearings on a calendar. But bearing failure doesn't follow a calendar — it follows conditions. Water intrusion, overloading, a loose castle nut, contaminated grease — any of these can put a bearing on the failure path well before the next scheduled service.
Continuous axle temperature monitoring catches these off-schedule failures by detecting the first sign of trouble: heat. A bearing running 20°F hotter than its partner on the other side is telling you something — long before it makes noise, long before you feel wobble, long before the hub starts smoking.
Trailer axles use tapered roller bearings — the same type found in many older vehicles and truck axles. However, the sizes are different. You can't use a bearing from your car on your trailer (or vice versa). Always match by bearing number or spindle measurement, not by eyeballing it.
Yes, as long as the bearing number matches. The numbering system (L44649, 25580, etc.) is an industry standard — a Timken L44649 is dimensionally identical to an SKF L44649 or a National L44649. Quality may vary between brands, but dimensions are standardized.
Some trailer manufacturers use non-standard or proprietary hub and spindle configurations. If your bearing number doesn't match common trailer bearings, check with the trailer or axle manufacturer. You can also cross-reference the number on any bearing supplier's website to find the exact dimensions and matching race.
Yes. Always. The bearing and race wear together as a matched set. A new bearing in a worn race will wear out faster, run hotter, and may not maintain proper clearance. Races are included in most bearing kits and cost very little on their own ($5-10 each).
The race press-fits into the hub bore. To remove it, flip the hub over and use a brass punch or race driver to tap it out from the back side, alternating around the circumference to walk it out evenly. Don't use a steel punch on a steel race — you'll damage the hub bore. New races get installed the same way in reverse, tapping them in squarely until they seat flush against the hub shoulder.
EZ Lube (or similar) spindles have a grease fitting on the end that lets you add grease without pulling the hub. This is convenient for topping off between services, but it does not replace a full repack. Over time, old grease accumulates and can trap contaminants. Full disassembly, cleaning, and repacking is still necessary at regular intervals.
Some boat trailer owners upgrade to oil bath hubs, which submerge the bearings in oil rather than packing them with grease. Oil bath hubs offer better lubrication consistency and are more forgiving of occasional submersion, but they require checking the oil level before each trip and replacing the oil on the same interval as a grease repack. They're a good upgrade if you launch frequently.
Yes, for standard Dexter, Lippert, or similar axles used in travel trailers and RVs. Match by axle weight rating. However, some larger RVs use unitized hub assemblies or other configurations. Check your owner's manual or the axle manufacturer's specs if you have a larger Class A or fifth wheel.
