3.5k Trailer Axle – 3500 lb Idler – (4″ Drop)

(2 customer reviews)


Featuring a standard 4″ drop for improved loading efficiency and crafted with high-strength steel, the Mrovi 3.5K Drop Idler Trailer Axle is designed for light-duty trailers needing reliable performance. Perfect for various applications, from utility to RV trailers, and optimized for quick 24-hour delivery across New Jersey.


  • 3,500 lbs Trailer Axle (3.5K Capacity)
  • Tube: 2 3/8″
  • Standard 4″ Drop
  • Idler

Please reference our Min/Max Chart Below for Axle sizing.


Earn up to 7,790 Points.



Elevate Your Towing with Mrovi’s 3.5K Drop Idler Trailer Axle

Mrovi Trailer Parts introduces the robust 3.5K Drop Idler Trailer Axle, an essential upgrade for your utility, cargo, ATV, lawn & landscape, motorcycle, BBQ pit, cargo, enclosed, or RV trailer. Crafted for versatility and durability, this axle is designed to keep your trailer performing optimally on every journey.




Helps for a smoother ride,
saves tires from wear and
helps the longevity of



  • 3,500 lbs  Trailer Axle (3.5K Capacity)
  • Tube: 2 3/8″
  • Standard 4″ Drop
  • Idler


  • Axles come fully assembled
    • Packed with High-Temp Axle Grease
  • Axle comes with loose spring seats that will need to be welded on
  • EZ Lube Design
    • Removable rubber plug on the hub cap with easy access to a grease-able zerk fitting
    • Grease your axle without pulling off your whole entire hub
  • High Strength Steel Axle Tube Construction to ensure
  • Designed for use on Light Duty Trailers
    • Utility Trailer Axle, Boat Trailer Axle, Car Haulers Trailer Axle, ATV Trailer Axle, Lawn & Landscape Trailer Axle, Motorcycle Trailer Axle, BBQ Pit Trailer Axle, Cargo Trailer Axle, Enclosed Trailer Axle, RV Trailer Axle & More

Why Choose a Drop Axle?

A drop axle offers a lower ride height, providing easier loading and unloading, improved stability, and a smoother towing experience. It’s an ideal choice for heavy-duty applications or when transporting delicate cargo that demands a gentle ride.

Effortless Installation & Maintenance

Our axle arrives fully assembled, including a high-temp axle grease, significantly simplifying the installation process. The EZ Lube Design allows for easy access to grease-able zerk fittings, enabling quick maintenance without the need to dismantle the hub. For those requiring customization, the axle features loose spring seats that need welding, allowing for a tailored fit to your trailer’s specifications.

Optimal Performance and Durability

Constructed from high-strength steel, the 3.5K Drop Idler Trailer Axle is built to endure, ensuring even tire wear and a superior towing experience. Whether you’re navigating the bustling streets of New Jersey or the quiet backroads, this axle guarantees reliability.

Comprehensive Internal Components

The axle kit includes a complete bearing kit with inner and outer bearings, tang washer, hub/dust/grease cap, cotter pin, outer race, inner race, and a double lip grease seal, ensuring you have all necessary components for a seamless setup.

Additional information


73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96

Bolt Pattern

5 x 4.5, 5 x 5

Axle Option

Axle Only ($349), Complete Kit ($779)

Bolt Pattern

MROVI’s Guide for Measuring Trailer Axle Bolt Patterns

How to Measure your Trailer’s Wheel Bolt Circle Lug or Bolt Pattern

In order to replace a hub on your trailer, you will need to know the bolt pattern or lug pattern. Trailer wheel hub patterns can be defined by the number of bolts or lugs per wheel and the diameter of the circle that the bolts are arranged on.  Determining the bolt pattern is rather easy, but it is very important that accurate measurements are taken.  The majority of boat trailers on the road have a 4, 5 or 6 lug pattern.

Determining the bolt pattern on your trailer:

  1. You will need to first count the number of lug bolts on one wheel. Most trailer hubs typically have 4 or 5 lugs per wheel/hub. Heavier duty, higher capacity trailers generally have 6 or 8 Lugs per wheel.
  2. If the trailer hubs have an even number of bolts holding the wheel, measure from the center of one bolt to the center of the bolt directly opposite using a ruler, tape measure or caliper.  The hub lug bolt pattern will be determined by the number of lug bolts and the distance between the opposing hub bolt (see 4-lug hub diagram).  All but 5-lug patterns are measured in this manner.
  3. If your trailer wheel hubs have 5 lug bolts, measuring is slightly different. Choose any lug bolt and measure the distance between the back of one lug to the center of another that is directly across from it. Be sure that you skip one bolt when measuring.  You can measure the distance in either direction
NOTE:  If you are replacing older wheel hubs, wheels, integrated hub/drums or hub/rotors the bearings should be checked for wear and replaced as necessary. Always use a high-temperature wheel bearing grease when re-packing your trailers hubs.

Hub Face & Spring Center

Axle Min/Max Sizes

Chart displaying minimum and maximum sizes for trailer axles, including hub face to hub face, spring center, and overall length measurements
Chart showing the minimum and maximum sizes for trailer axles, including critical measurements such as hub face to hub face, spring center, and overall length. Ensure accurate measurements for optimal trailer performance and safety.

Understanding Min/Max Measurements for a Trailer Axle

When dealing with trailer axles, understanding the minimum and maximum measurements is crucial for ensuring a proper fit, safe operation, and optimal performance. These measurements help determine the correct axle size for your trailer and ensure it can handle the required load.

1. Hub Face to Hub Face (HF to HF) Measurement

  • Definition: The distance from the outer edge of one hub face to the outer edge of the other hub face.
  • Importance: This measurement determines the overall length of the axle and ensures that the wheels are correctly positioned under the trailer. The correct HF to HF measurement ensures that the wheels do not extend beyond the trailer’s sides or sit too far inward.

2. Spring Center (SC) Measurement

  • Definition: The distance between the center of one spring mount to the center of the opposite spring mount.
  • Importance: This measurement ensures the axle aligns properly with the trailer’s spring hangers. Correct spring center measurement is crucial for balanced load distribution and maintaining the trailer’s stability and alignment during towing.

3. Overall Length (OL) Measurement

  • Definition: The total length of the axle from end to end.
  • Importance: This includes the hub face distance and any additional parts extending beyond the hub faces. Knowing the overall length helps in understanding the space needed for axle installation and avoiding any potential obstructions.

Min/Max Measurements

Minimum Measurements:

  • Hub Face to Hub Face (HF to HF): The minimum HF to HF measurement ensures the wheels fit within the trailer frame without rubbing against the trailer’s body or fenders.
  • Spring Center (SC): The minimum SC measurement ensures that the axle can be securely mounted to the trailer frame with the existing spring hanger placements.
  • Overall Length (OL): The minimum overall length ensures the axle fits within the designated area of the trailer without interfering with other components.

Maximum Measurements:

  • Hub Face to Hub Face (HF to HF): The maximum HF to HF measurement ensures the wheels are not too far apart, which could lead to excessive stress on the axle and poor handling.
  • Spring Center (SC): The maximum SC measurement ensures the axle is adequately supported by the trailer’s spring hangers and prevents excessive flexing or bending.
  • Overall Length (OL): The maximum overall length ensures the axle does not extend too far beyond the trailer, which could affect the trailer’s balance and aerodynamics.

Why Min/Max Measurements Matter

  1. Safety: Ensuring that the axle fits within the specified measurements prevents issues such as improper wheel alignment, excessive tire wear, and instability during towing, which can lead to accidents.
  2. Performance: Proper axle measurements ensure balanced load distribution and optimal suspension performance, leading to a smoother and more efficient towing experience.
  3. Compliance: Adhering to the correct measurements ensures the trailer meets industry standards and regulations, preventing potential legal issues and ensuring roadworthiness.
  4. Durability: Correct axle fitment reduces stress on trailer components, preventing premature wear and extending the lifespan of the axle and associated parts.

Measuring Tips

  • Accurate Tools: Use a reliable measuring tape or laser measurement tool to ensure precision.
  • Level Surface: Ensure the trailer is on a level surface to avoid skewed measurements.
  • Multiple Checks: Measure multiple times to confirm accuracy, and consult the trailer manufacturer’s specifications for guidance.

By understanding and adhering to the minimum and maximum measurements for your trailer axle, you can ensure a safe, reliable, and efficient towing experience.

2 reviews for 3.5k Trailer Axle – 3500 lb Idler – (4″ Drop)

  1. Robin Hood

    Great prices. They have every trailer part in stock. 3.5k trailer axles were extraordinary…

  2. Sam

    3.5k trailer axles are available in stock. These are new and very helpful. Reasonable prices ☺

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