Heavy Duty 7K to 8K Hybrid Trailer Hub Drum 8x6.5 5/8 Studs Upgrade Complete Kit
Upgrade your 7,000 lb axle with 8,000 lb capacity bearings and heavy-duty 5/8" studs for maximum durability and service life.
Overview
This Hybrid Hub & Drum is the ultimate "beefed-up" solution for standard 7,000 lb trailer axles. While it is cast to fit standard 12-1/4" trailer brakes, it is precision-machined to accept larger 8,000 lb capacity bearing sets and robust 5/8" wheel studs. This kit provides a significant strength advantage over standard 7K hubs that typically use 1/2" studs and smaller outer bearings, making it a favorite for high-demand equipment haulers and dump trailers.
R&P Service Insight
Why the Hybrid design matters for commercial and heavy-duty towing:
- Increased Bearing Life: Uses the larger #02475 outer bearing for better load distribution.
- Shear Strength: 5/8" studs provide superior clamping force compared to 1/2" alternatives.
- Standard Compatibility: Fits common 12-1/4" electric or hydraulic brakes.
R&P Knowledge Hub
Compatibility: Designed for 7,000 lb and 8,000 lb capacity trailer axles.
Vehicle / System Fit: Common on Kaufman, Sure-Trac, and Lippert/LCI heavy-duty trailer brands.
Installation Notes: Verify your spindle sizes match the #25580 inner and #02475 outer bearings before ordering.
Performance Insight: The use of 8K internals on a 7K-size drum offers a higher safety margin for heavy-duty commercial towing applications.
Brand & Fitment Note
Selling Brand: R&P Carriages / Verified Aftermarket Upgrade Kit
Application Reference: Any OEM or platform names in this listing (such as Lippert, Kaufman, or Sure-Trac) describe compatibility, fitment target, or application style only where supported by verified dimensions.
What This Means: This listing is for a curated R&P heavy-duty upgrade kit, designed as a high-performance replacement for standard-spec 7K components.
Before Ordering: Verify wheel pilot hole (4.75"), stud clearance (5/8"), and spindle seal surface (2.25") before installation.
R&P Repair Insight
Before ordering, please perform these three critical checks to ensure a perfect fit for your trailer:
- Wheel Pilot Hole: These hubs require a 4.75" hub-centric pilot hole on the rim.
- Stud Size: Ensure your wheels can accept 5/8" studs; standard 7K wheels are often bored only for 1/2" studs.
- Seal Surface: Confirm your spindle's seal seat is compatible with the 2.25" ID grease seal (10-63).
Features
High-Strength Casting
Heavy-duty cast iron construction with pre-pressed races for immediate installation.
Premium Bearings
Includes #25580 inner and #02475 outer bearings for increased load endurance.
Double-Lip Seal
Equipped with a 10-63 grease seal to keep contaminants out and lubrication in.
5/8" Stud Upgrade
Larger 5/8"-18 studs provide superior wheel retention for heavy-duty hauling.
Specifications
| Specification | Detail |
|---|---|
| Part Number | 99-865-58HD-KIT |
| Bolt Pattern | 8 on 6.5" |
| Axle Rating | 7,000 - 8,000 lbs |
| Drum Size | 12-1/4" x 2-1/2" |
| Stud Diameter | 5/8"-18 |
| Inner Bearing | #25580 (1.75" ID) |
| Outer Bearing | #02475 (1.25" ID) |
| Grease Seal | 10-63 (2.25" ID) |
Fitment / Application
| Category | Details |
|---|---|
| System | Trailer Braking Axle |
| Primary Fit | 7K - 8K Spindles |
| Brake Match | 12-1/4" Assemblies |
| Notes | Must verify wheel pilot hole (4.75") and stud clearance. |
Included Components
| Quantity | Item |
|---|---|
| 1 | Hybrid Hub & Drum (Cast Iron) |
| 1 | Inner Bearing #25580 |
| 1 | Outer Bearing #02475 |
| 1 | Double-Lip Grease Seal (10-63) |
| 1 | Grease Cap (Drive-in Style) |
