3.5K Axle Beam Kit – 4" Drop – 61.5" Hub Face – 2.4" Tube – Loose Perches
Bare 3,500 lb trailer axle beam kit with 4" drop configuration, 61.5" hub face, 2.4" tube, and two loose spring perches for trailer or camper axle replacement work.
Overview
This 3.5K trailer axle beam kit is built for replacement axle work on trailers or campers that commonly use a 61.5" hub face axle, 2.4" tube, 5-lug hubs, or 10" drum brake setups. This listing includes the bare axle beam and two loose spring perches. Bearings, seals, hubs, drums, brakes, and welded perch placement are not included unless separately specified.
R&P Service Insight
Axle fit is measurement-driven. Before ordering, confirm hub face, spring center, axle capacity, brake/hub style, bearing set, and whether the trailer requires a drop axle configuration.
- Hub Face Matters: This axle is listed as a 61.5" hub face axle beam.
- Loose Perches: The included spring perches ship loose by default and must be positioned and welded before use.
- Camber Direction: If the axle is cambered, the arch goes up in the middle when installed.
R&P Knowledge Hub
Compatibility: Common replacement axle for trailers or campers that typically have 43.5" to 49.5" floor deck width and use compatible 5-lug hubs or 10" drum brake assemblies.
Vehicle / System Fit: Trailer axle replacement applications where the axle capacity, hub face, brake/hub configuration, bearing set, seal style, tube size, and drop configuration match.
Installation Notes: Spring perches are included loose and are not welded on by default. The axle must not be installed, towed, or placed in service until the perches are correctly measured, squared, positioned, and welded.
Performance Insight: The 2.4" tube and cambered axle design are common in 3,500 lb trailer running gear setups where correct measurement and installation alignment are critical.
Brand & Fitment Note
Selling Brand: R&P Carriages curated axle beam kit.
Application Reference: Any manufacturer, hub, brake, bearing, or trailer style references in this listing describe compatibility targets only where measurements and configuration match.
What This Means: This listing is for a trailer axle beam kit with loose spring perches, not a complete hub/drum/brake axle assembly unless additional components are separately purchased or listed.
Before Ordering: Verify hub face, spring center, axle capacity, drop style, tube diameter, bearing set, seal style, hub/drum compatibility, brake flange needs, and included components before installation.
R&P Repair Insight
The most common axle-ordering mistakes come from measuring the wrong points or assuming included perches are already welded. This kit requires a real spring center measurement before welded perch placement can be confirmed.
- Measure Hub Face: Confirm the hub face requirement before replacing an existing axle beam.
- Confirm Bearing Set: This axle is listed for standard L44649 / L68149 bearings and 10-19 seals; bearings and seals are not included.
- Do Not Guess Spring Center: Measure center-to-center at the leaf springs or existing spring perches before requesting welded perch placement.
Features
3.5K Replacement Axle Beam
Designed for 3,500 lb trailer axle replacement applications where the listed measurements and running gear configuration match.
4" Drop Configuration
Drop axle layout for trailers or campers requiring a lower axle beam profile than a straight axle setup.
2.4" Axle Tube
Standard 2.4" tube configuration, with matching loose spring perches included for weld-on installation.
Common Bearing Compatibility
Listed for standard L44649 / L68149 bearings and 10-19 seals. Bearings and seals are not included.
Specifications
| Specification | Detail |
|---|---|
| Part Number | 3500-615-24-D-KIT |
| Product Type | Bare trailer axle beam kit with loose spring perches |
| Axle Capacity | 3,500 lb |
| Axle Style | 4" drop axle beam |
| Hub Face | 61.5" |
| Tube Diameter | 2.4" |
| Brake Flange to Flange | 55.16" |
| Bearing Shoulder to Shoulder | 57.69" |
| Spindle End to End | 65.88" |
| Bearing Reference | L44649 / L68149 bearings |
| Seal Reference | 10-19 seals |
| Bearings / Seals Included | No |
| Spring Perches | Two loose spring perches included; not welded by default |
| Origin Note | USA Made per supplied listing description |
Fitment / Application
| Category | Details |
|---|---|
| Vehicle / System | Trailer or camper axle replacement |
| Primary Fit | Trailers using compatible 3,500 lb axle dimensions and 61.5" hub face measurement |
| Common Setup | Applications that typically use 5-lug hubs or 10" drum brake assemblies |
| Deck Width Reference | Commonly used on trailers or campers with approximately 43.5" to 49.5" floor deck width when all axle measurements match |
| Important Note | Deck width is only a reference. Always verify hub face, spring center, axle capacity, tube size, brake/hub configuration, and bearing/seal compatibility before ordering. |
Included Components
| Quantity | Item |
|---|---|
| 1 | 3500-615-24-D-KIT · 3.5K bare trailer axle beam, 61.5" hub face, 2.4" tube, 4" drop, EZ Lube style reference per supplied listing |
| 2 | SP-2375 · Spring perch for 2.4" axle beam |
| Not Included | Bearings, races, seals, hubs, drums, brake assemblies, u-bolts, plates, nuts, washers, and welded perch placement unless separately specified |
What Comes in the -KIT: Spring Perches Are Included Loose
This -KIT includes the axle beam and loose spring perches / spring seats. The spring perches are included as separate pieces. Included does not mean welded.
Spring perches ship loose by default. They are not welded to the axle tube before shipment unless the customer specifically requests perch welding in the order notes, provides the correct Spring Center measurement, and R&P confirms the weld-on request before the axle ships.
Repetition matters: If the listing says “spring perches included,” that means loose spring perches are included with the kit. It does not mean the spring perches are already installed, welded, or ready for towing.
When Will R&P Weld the Spring Perches?
R&P may weld the spring perches before shipment only when the order clearly gives us the information needed to do it correctly.
- The customer must request welded spring perches in the order notes.
- The customer must provide the Spring Center measurement.
- R&P must confirm the weld-on request before shipment.
How to Find Your Spring Center Measurement
Spring Center is the distance from the center of one leaf spring to the center of the opposite leaf spring. This is the measurement used to locate where the spring perches need to be welded on the axle tube.
- Best method with old axle: Measure from the center of one existing spring perch / spring seat to the center of the opposite spring perch / spring seat.
- Best method from the trailer: Measure from the centerline of the left leaf spring pack to the centerline of the right leaf spring pack where the axle sits.
- Leaf spring center bolt method: Measure from the center of the center bolt / locating pin on one spring pack to the center of the center bolt / locating pin on the other spring pack.
- Do not measure outside-to-outside. Spring Center is a center-to-center measurement.
- Do not guess from deck width. Deck width can be helpful context, but it is not a substitute for the actual Spring Center measurement.
Axle Measurement Diagram
Use the axle measurement diagram below as a visual reference while confirming axle dimensions and installation details. Spring Center must still be measured center-to-center at the trailer’s leaf springs or existing spring perches.
Why Welding the Perches Matters
This image shows a real-world installation problem where loose spring perches were not welded before use and brake wiring was torn out. This is exactly why the axle must not be installed, towed, or placed into service while the spring perches are still loose.
Loose perches can allow the axle to move or rotate out of its intended installed position. That can damage brake wiring, brake components, suspension parts, tires, and the trailer. The perches must be properly welded before road use.
| Question | Answer |
|---|---|
| Are spring perches included in the -KIT? | Yes. The spring perches / spring seats are included as loose parts. |
| Are the spring perches welded on by default? | No. They ship loose by default. |
| Can R&P weld the perches before shipping? | Only if the customer requests it in the order notes, provides the correct Spring Center measurement, and R&P confirms the request before shipment. |
| What measurement is needed for welding? | Spring Center: center of one leaf spring / spring perch to the center of the opposite leaf spring / spring perch. |
| Can the axle be used with loose perches? | No. Do not install, tow, or place the axle in service until the perches are properly welded. |
| What can happen if perches are not welded? | Loose perches can allow the axle to move or rotate, which can damage brake wiring, brake parts, suspension components, tires, and the trailer. |
| Which way does camber face? | If the axle is cambered, the arch goes up in the middle when installed. |
Order Note Wording Customers Can Use
Customers who want R&P to weld the spring perches should put clear instructions in the order notes before checkout.
