Identify Trailer Bearing Protectors by Hub Bore & MPN

Trailer bearing protectors take the place of conventional hub dust caps, using a grease reservoir and spring-loaded mechanism to help keep water and road debris away from wheel bearings. The correct fit depends on the inside diameter of the hub opening, not the wheel diameter or how many lug nuts are fitted. Use this guide to compare exact CURT and C.E. Smith numbers, plus the dust covers sold separately.

Compare hub-bore sizes before selecting a protector

CURT specifies 1.98 inches for 22198, 2.32 inches for 22232, and 2.44 inches for 22244. C.E. Smith lists 16271 for a 1.985-inch hub opening. These are separate manufacturer specifications. The small numerical difference between 1.98 and 1.985 inches does not establish cross-brand interchangeability or acceptable interference fit.

How to identify the hub opening

1. Identify the existing hub. Find its service part number or the original bearing-protector number, where available. Confirm the hub and bearing service arrangement.
2. Remove and inspect the old cap correctly. Follow the axle or hub manufacturer's maintenance instructions. Check for damage, loose bearings, degraded grease or a failed grease seal.
3. Measure the hub bore. Use suitable precision measuring equipment to check the clean, round inside opening where the protector seats. Do not substitute the outside hub diameter, wheel size or wheel bolt pattern.
4. Choose the exact manufacturer-specified diameter. Compare the measured bore and original part number with the corresponding CURT or C.E. Smith application. Do not round an uncertain measurement into the nearest catalog size.
5. Install and lubricate correctly. Follow the protector manufacturer's installation and grease-filling instructions. Overfilling or improper installation can harm grease seals, while a loose protector may be lost in service.

What is the outer dust cover for?

The flexible outer cover protects the exposed grease fitting and mechanism from grit and splashes. It is not the pressure-maintaining metal protector and it does not replace a bearing seal. If the steel protector is firmly installed but its rubber or plastic outer cover is missing, the correct replacement cover may be all you need. Match the cover to the exact protector family.

Boat trailers deserve particular attention because warm hubs may enter cool water at the launch ramp. Their lubrication system must still be inspected and serviced as directed; no bearing protector eliminates the need for regular bearing and seal maintenance.

Shop exact bearing protectors and covers

Each card opens a matching UsedRVParts.ca listing. Check live stock and condition before ordering. The store carries brand-new products as well as used RV parts; eligible used inventory can be inspected and collected in Kelowna by appointment.

CURT 22198

Bearing protector pair

1.98-inch hub bore

Check product details and condition

CURT 22232

Bearing protector pair

2.32-inch hub bore

Check product details and condition

CURT 22244

Bearing protector pair

2.44-inch hub bore

Check product details and condition

C.E. Smith 16271

Chrome bearing protector pair with bras

1.985-inch hub bore

Check product details and condition

CURT 23198

Replacement dust covers

For CURT 1.98-inch protector family

Check product details and condition

Related axle and hub service references

For bearing, seal and hub components beyond the grease cap, see the Dexter 3,500 lb E-Z Lube hub parts diagram and Dexter 5,200/6,000 lb hub parts guide. E-Z Lube and other hub-lubrication systems have their own service procedures and should not be assumed to use an ordinary spring-loaded bearing protector.