GREASE CAPS | AXLE CAPS

CUSTOM SIZING • GALVANIZED • ZINC AVAILABLE

axle grease caps

Grease Caps Built for a Secure, Reliable Fit

Shield wheel bearings and hub assemblies from moisture, dirt, and road contaminants with precision-engineered axle caps and grease cap solutions. Leveraging advanced custom metal stamping, Wedge Products manufactures durable caps across standard dimensions to serve automotive, agricultural, trailer, and industrial operations.

Grease Cap Size Selector — Wedge Products

Grease Cap Size Selector

All dimensions in inches

Remove the existing cap and measure the inside diameter of the hub bore where the new cap installs — not the outside of the old cap. A caliper is recommended for accuracy.

A — Diameter
B — Length under flange
C — Overall height
Caliper reading of the hub bore inside diameter. Nearest nominal A shown.

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Durable Grease & Axle Caps

Protect wheel bearings with galvanized or zinc-plated caps made to fit your exact trailer or RV specs.

How to Measure Your Grease Cap

Selecting the correct grease cap starts with an accurate measurement. Remove the existing cap and measure the inside diameter of the hub bore where the new cap will be installed—not the outside of the old cap. Once you have your measurement, compare it to the grease cap sizes and specifications above to find the correct fit.

For the best results, use a caliper to measure as accurately as possible. If you’re replacing a damaged or missing cap and aren’t sure which size you need, contact Wedge Products for assistance in selecting the right replacement.

Grease Cap Customers

  • Monitor Manufacturing
  • Industrial Axle
  • Dexter Marine
  • Martin Wheel
  • QDS
  • Briggs & Stratton
  • MTD
  • Cequent Trailer Products
  • E-Z GO Textron
  • Snapper
  • Secondary Machining
  • Tie-Down Engineering
  • Dexter Axle
  • Redneck Trailer Supply
  • Martin Wheel
  • QDS
grease cap

Axle Grease Cap FAQs

A B C
Grease Cap Specifications Part
No.		 Diameter Length
Under Flange		 Overall
Height		 Mat
Thickness
trailer dust cap Note: Can be furnished
with 1-3/16″ diameter hole. * R = .650		 21-2 1.781 .27 .875 .03
21-3B 1.985 .31 1.20 .03
21-3A 1.990 .31 1.25 .03
21-1A 2.450 .25 1.34 .03
21-4 2.705 .533 2.063 .03
21-6 2.841 .37 1.12 .042
21-8 3.630 .50 1.875 .03
Rubber Plugs for Lube Caps
boat trailer grease caps 1478 Call for
available price/quantity breaks.
Wedge Rubber Plugs – Now Available In RED and YELLOW
A B C
Grease Cap Specifications Part
No.		 Diameter Length
Under Flange		 Overall
Height		 Mat
Thickness
grease caps, dust caps 21-41-1 1.990 .31 1.400 .03
21-42-1 2.450 .31 1.525 .03
21-43-1 2.725 .31 1.525 .03
21-44-1 3.630 .50 1.625 .03
A B C
Grease Cap Specifications Part
No.		 Diameter Length
Under Flange		 Overall
Height		 Mat
Thickness
grease caps, dust caps 21-39 2.720 .31 1.34 .06
1005 3.160 .38 1.78 .06
21-40 4.734 .236 1.811 .06
21-50 5.667 .437 1.656 .03

A grease cap, also known as a dust cap or hub cap, is a protective covering used in automotive and machinery applications to safeguard wheel bearings from contaminants and to retain lubricating grease within the bearing assembly.

No, trailer dust caps are not universally the same size. The size of trailer dust caps varies depending on the specific trailer axle and wheel assembly. Different trailer types and manufacturers use different hub and bearing setups, which means selecting the right wheel bearing dust cap by size is essential to ensure a proper fit and reliable protection.

The choice between metal and plastic dust caps depends on various factors, including the specific application, environmental conditions, and personal preferences. Both metal and plastic dust caps have their advantages and disadvantages.

Metal Dust Caps:

Durability: Metal dust caps, often made of steel or aluminum, tend to be more durable and resistant to wear and tear. They are less likely to crack or break under stress or harsh conditions.

Temperature Resistance: Metal dust caps typically have better heat resistance compared to plastic. This can be an important factor in applications where high temperatures are a consideration.

Longevity: Due to their durability, metal dust caps may have a longer lifespan, making them suitable for heavy-duty or high-impact environments.

Plastic Dust Caps:

Corrosion Resistance: Plastic dust caps are generally more resistant to corrosion, making them a good choice for applications where exposure to moisture or chemicals is a concern.

Lightweight: Plastic dust caps are lighter than metal ones, which may be advantageous in situations where minimizing weight is a priority, such as in certain automotive or aerospace applications.

Cost: Plastic dust caps are often less expensive than metal ones, making them a cost-effective choice, especially for applications where budget considerations are important.

Our wide selection of trailer dust cap sizes ensures a proper fit for a variety of trailer models. Each trailer axle grease cap is designed to protect wheel bearings from dirt, moisture, and other contaminants, helping to extend the life of your axle components and maintain smooth trailer operation.

We provide accurate bearing dust cap sizes to make maintenance and replacements simple and efficient. Using the correct trailer axle grease cap prevents corrosion, reduces wear on critical components, and keeps trailers running safely under heavy loads.

Choosing the right trailer dust cap sizes and bearing dust cap sizes is essential for long-term durability and reliable trailer performance. Our high-quality trailer axle grease cap products are built for a secure fit, protecting bearings and ensuring consistent performance over time.

Boat trailer grease caps protect wheel bearings by sealing the hub to prevent contamination from water, dirt, and debris, which is especially important for trailers frequently exposed to submersion and harsh environments.

A trailer dust cap is a small, round metal cover that fits tightly over the end of the hub. It typically has a smooth or slightly grooved finish and they also may sit flush with the hub or extend out a bit, depending on if it’s a drive-in or threaded type.

Built for a secure fit and dependable performance, Wedge grease caps help protect wheel bearings from dirt, moisture, and contaminants that can lead to premature wear. Manufactured to precise specifications, our grease caps are available in a variety of sizes to fit a wide range of trailer, agricultural, automotive, and industrial hubs.

Whether you’re replacing a worn grease cap or sourcing components for new equipment, Wedge Products delivers reliable solutions backed by decades of manufacturing experience.

Need protective caps for pipe, tubing, or fabricated components? Explore Wedge Products’ pipe caps and end caps available in standard and custom sizes.

trailer dust cap sizes

An Aerospace
Certified Stamper

Certified to AS9100 Rev. D, Wedge Products is an experienced aerospace parts manufacturer providing stamped metal components to the aerospace, military and industry.