Rockwell American Tandem 3,500 lb Trailer Axle Kits – Brakes on 1 Axle

Rockwell American Tandem 3,500 lb Trailer Axle Kits – Brakes on 1 Axle

Build, repair, or upgrade your trailer with genuine Rockwell American Tandem 3,500 lb Trailer Axle Kits featuring electric brakes on one axle and an idler axle on the other. Designed for utility trailers, cargo trailers, landscape trailers, car haulers, and light equipment trailers, these kits provide dependable braking performance while offering a practical and cost-effective tandem axle solution.

Available in Axles Only, Suspension Kit, Build Kit, and Running Gear Kit configurations, each package includes carefully matched components for trailer repairs, running gear replacement, or complete trailer construction. Multiple hub face, spring center, and bolt pattern options are available to match your trailer setup.

Rockwell American trailer axles are part of the Dexter family of trailer axle brands and feature Posi-Lube® greaseable spindles, cambered axle beams, durable powder-coated construction, and pre-installed 10″ x 2-1/4″ electric brake assemblies on one axle. Running Gear Kits also include 15″ wheels with ST205/75R15 radial trailer tires for a complete running gear solution.

Made in America. Free Shipping in the Lower 48 States.

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Compare Kit Options

Select the tandem trailer axle package that best matches your trailer repair, replacement, or new trailer build requirements.

← Swipe left/right to compare all kit options →

Axles Only: Includes one Rockwell American 3,500 lb electric brake axle and one 3,500 lb idler axle with pre-installed hubs, brake assemblies, and Posi-Lube® greaseable spindles. Ideal for replacing an existing tandem axle set while reusing compatible suspension components.

Suspension Kit: Includes both axles, four double-eye leaf springs, and two U-bolt kits for replacing the primary axle and suspension components on a tandem trailer.

Build Kit: Includes everything in the Suspension Kit plus a complete tandem axle hanger kit. This configuration is well suited for new trailer construction, frame-up builds, and complete suspension replacement.

Running Gear Kit: Includes everything in the Build Kit plus four 15″ wheels and ST205/75R15 radial trailer tires for a complete tandem running gear package.

Axles Only and Suspension Kit configurations are commonly selected for repairs and partial upgrades. Build Kit and Running Gear Kit configurations are better suited for complete trailer builds and major running gear replacements.

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Choose Your Axle Size (Hub Face / Spring Center)

Select the hub face (HF) and spring center (SC) measurements that match your trailer frame and suspension setup. Correct measurements help ensure proper wheel positioning, suspension alignment, tire clearance, and overall trailer fitment.

• Hub Face (HF): Measure from the wheel-mounting surface on one hub to the wheel-mounting surface on the opposite hub.
• Spring Center (SC): Measure from the center of one spring seat to the center of the opposite spring seat.

Important: Measure your existing axles before ordering. Do not select replacement axles based only on trailer deck width, frame width, fender spacing, or overall trailer width.

Not sure which axle size you need? Read our How to Measure a Trailer Axle Guide or contact us, and we’ll help verify your measurements before you order.

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Why Choose Rockwell American?

• Made in America: Genuine Rockwell American trailer axle components manufactured in the USA and backed by the Dexter family of trailer axle brands.
• 7,000 lb Combined Axle Capacity: Tandem configuration with one 3,500 lb electric brake axle and one 3,500 lb idler axle.
• Electric Brakes on One Axle: Pre-installed 10″ x 2-1/4″ electric brake assemblies provide dependable stopping support while reducing cost compared to tandem systems equipped with brakes on both axles.
• Posi-Lube® Spindles: Integrated grease fittings simplify routine bearing lubrication without removing the hubs.
• Cambered Axle Beams: Engineered to promote proper wheel tracking, even tire wear, and stable towing under load.
• Durable Powder-Coated Finish: Helps protect against corrosion, road debris, weather exposure, and everyday trailer use.

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Brakes on One Axle

This tandem configuration combines one electric brake axle with one idler axle. It provides trailer braking support while keeping the system simpler and more affordable than a tandem setup equipped with electric brakes on both axles.

Brake requirements vary by trailer weight, application, and location. Always verify applicable state, provincial, and local brake requirements before operating the trailer. Proper trailer wiring, brake adjustment, breakaway-system operation, and tow-vehicle brake-controller setup are required for dependable performance.

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Posi-Lube® Spindle System

Rockwell American Posi-Lube® spindles include integrated grease fittings that direct lubricant through the spindle and into the hub assembly. This design makes routine bearing lubrication more convenient and helps support dependable hub and bearing performance.

Posi-Lube® does not eliminate the need for periodic hub inspection, bearing service, brake inspection, grease-seal replacement, or other routine trailer maintenance.

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Common Applications

• Utility Trailers
• Cargo Trailers
• Landscape Trailers
• Car Haulers
• Light Equipment Trailers
• ATV and UTV Trailers
• Farm and Property Trailers
• Custom Tandem Trailer Builds

These kits are well suited for trailer repairs, complete running gear replacement, and new tandem trailer construction across a wide range of light-duty towing applications.

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Fitment & Capacity Notes

• Verify your hub face (HF) and spring center (SC) measurements before ordering.
• Confirm the selected bolt pattern matches your existing or planned trailer wheels.
• Verify wheel, tire, suspension, brake, and trailer frame ratings before loading.
• Check for adequate tire, fender, and frame clearance throughout suspension travel.
• Confirm the tow vehicle has a compatible brake controller and properly functioning trailer wiring.
• The 7,000 lb combined axle capacity does not determine trailer GVWR or payload capacity by itself.
• Overall trailer capacity is limited by the lowest-rated component in the complete trailer system.
• Hanger installation, axle alignment, and welding should be completed by a qualified trailer fabricator when applicable.

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Frequently Asked Questions

What is the difference between the kit options?

Axles Only includes one electric brake axle and one idler axle. The Suspension Kit adds four double-eye leaf springs and two U-bolt kits. The Build Kit adds a tandem axle hanger kit. The Running Gear Kit adds four 15″ wheels and ST205/75R15 radial trailer tires.

Why are brakes installed on only one axle?

This configuration combines one electric brake axle with one idler axle to provide braking support while reducing cost and maintenance compared to tandem axle systems equipped with brakes on both axles. It is commonly used on utility, cargo, landscape, and light equipment trailers where the configuration meets applicable brake requirements.

How do I measure my trailer axle?

Measure the hub face from one wheel-mounting surface to the opposite wheel-mounting surface. Measure the spring center from the center of one spring seat to the center of the opposite spring seat. Visit our How to Measure a Trailer Axle Guide for additional help.

What size brakes are included?

The electric brake axle includes pre-installed 10″ x 2-1/4″ electric brake assemblies with matching hub-and-drum assemblies.

Do I need a trailer brake controller?

Yes. Electric trailer brakes require a compatible in-cab brake controller, properly connected trailer wiring, and a functioning breakaway system where required.

What are Posi-Lube® spindles?

Posi-Lube® spindles use an integrated grease fitting and internal lubrication passage to help direct grease into the hub assembly during routine maintenance.

Can I reuse my existing trailer springs?

Yes, provided they match the axle capacity, spring width, spring length, and mounting configuration. Many customers choose the Suspension Kit or Build Kit when replacing worn suspension components at the same time.

Does the Running Gear Kit include wheels and tires?

Yes. The Running Gear Kit includes four 15″ wheels and ST205/75R15 radial trailer tires in addition to both axles and the complete suspension package.

What trailers commonly use this axle configuration?

These tandem 3,500 lb axle kits are commonly used on utility trailers, cargo trailers, landscape trailers, car haulers, ATV and UTV trailers, farm trailers, and light equipment trailers.

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Resources & Downloads

• Rockwell American Trailer Axle Service Guide
• Trailer Hanger Kit Spacing Guide
• How to Measure a Trailer Axle
• Johnson Trailer Parts YouTube Channel

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Installation Video

Watch our installation video for helpful guidance on trailer axle measurements, suspension setup, hanger placement, and replacement axle selection.

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Need Help?

Need help choosing the correct tandem axle size, bolt pattern, or kit configuration? Our knowledgeable team can help verify your measurements and fitment before you order.

Call or Text: (602) 292-9690
Email: sales@johnsontrailerparts.com