A strong tandem axle choice matches your trailer’s frame measurements and required load capacity, then supplies the suspension and brake components needed for installation. The six options here range from Polar’s trailer-specific walking-arm kit to complete electric-brake running gear rated for 7,000 to 14,000 pounds total. For a general-purpose upgrade, Salo Trailer Parts 7,000 lb Tandem Axle Kit stands out with two 7,000-pound axles, 89-inch hub face, 74-inch spring center, and pre-mounted tires.
Other kits suit narrower frames or different capacity needs, but their hub face, spring center, bolt pattern, and included parts vary. Check those dimensions against your trailer before ordering: capacity alone does not establish fit, and some kits target a particular frame width or trailer series.
Salo Trailer Parts 7,000 lb Tandem Axle Kit leads this lineup for buyers seeking a complete, high-capacity trailer running-gear replacement. It supplies two electric-brake axles rated at 7,000 pounds each, for 14,000 pounds total, plus springs, U-bolts, hangers, equalizers, shackles, and ST235/80R16 tires mounted on 8-lug wheels. Its 89-inch hub face and 74-inch spring center suit a specific fitment, so verify those measurements and the 8-on-6.5-inch bolt pattern before choosing it.
Our Top Picks
Best OverallSalo Trailer Parts 7,000 lb Kit
Two 7,000-pound electric-brake axles provide 14,000 pounds total, and the kit includes suspension hardware plus mounted ST235/80R16 tires.
View on Amazon
Best Narrow-Frame FitSalo Trailer Parts 5,200 lb Kit
Its 10,400-pound total capacity, 85-inch hub face, and 70-inch spring center target most 72-inch-wide frames; mounted tires are included.
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Best Standard FitRockwell American 5,200 lb Kit
Two 5,200-pound electric-brake axles deliver 10,400 pounds total, with an 89-inch hub face and 74-inch spring center for 76-inch frames.
View on Amazon- Best E-Z Lube Fit Dexter 3,500 lb Tandem Kit
Compare tandem axle kits by fit and capacity
| # | Product | Weight | Buy |
|---|---|---|---|
| 1 | 1. Salo Trailer Parts 7,000 lb KitBest Overall | — | View on Amazon |
| 2 | 2. Salo Trailer Parts 5,200 lb KitBest Narrow-Frame Fit | — | View on Amazon |
| 3 | 3. Rockwell American 5,200 lb KitBest Standard Fit | — | View on Amazon |
| 4 |  4. Dexter 3,500 lb Tandem KitBest E-Z Lube Fit | 200 lb | View on Amazon |
| 5 |  5. Johnson Trailer Parts 3,500 lb KitMixed brake-and-idler axle setups | 200 lb | View on Amazon |
| 6 |  6. Polar Trailer Tandem Axle KitPolar HD1200 and HD1500 owners | 41 lb | View on Amazon |
Detailed Reviews: Best Tandem Axles For Trailer
#1 · Best Overall
1. Salo Trailer Parts 7,000 lb Kit
Best for: High-capacity 8-lug trailer builds.
Why it ranks #1: Two 7,000-pound electric-brake axles provide 14,000 pounds total, and the kit includes suspension hardware plus mounted ST235/80R16 tires.
Two 7,000-pound electric-brake axles give this kit a 14,000-pound total capacity, supporting tandem trailers that need more rated running-gear capacity. It pairs them with ST235/80R16 radial tires already mounted on 8-lug wheels, plus suspension hardware for a fuller installation package.
The 89-inch hub face and 74-inch spring center specify the axle layout, while the stated fit is for 76-inch-wide trailer frames; those measurements help identify whether the kit matches a planned build. Two electric-brake axles, double-eye springs, U-bolt kits, equalizers, and shackles supply suspension and tandem hardware together. Pre-mounted ST235/80R16 tires and 8-lug wheels can reduce separate wheel-and-tire assembly work, but the 8-on-6.5-inch bolt pattern remains a key compatibility constraint.
- Two 7,000-pound electric-brake axles provide 14,000-pound total capacity.
- Includes double-eye leaf springs, U-bolt kits, equalizers, and shackles.
- ST235/80R16 radial tires come pre-mounted on 8-lug wheels.
- Lists 89-inch hub face and 74-inch spring center for 76-inch-wide frames.
- Its 8-on-6.5-inch bolt pattern limits wheel compatibility to matching setups.
Skip it if you need 5-lug wheels; the Johnson Trailer Parts 3500 lb Tandem Trailer Axle Kit uses a 5-on-4.5-inch pattern.
This kit suits builders or owners replacing running gear on a 76-inch-wide trailer needing 7,000-pound axles and pre-mounted tires. Its 89/74-inch geometry and 8-on-6.5-inch pattern define important fit boundaries.
Full product details
| Brand | Salo Trailer Parts |
|---|---|
| Item model number | STP-Tandem 7k Brake Axle Kit |
| Manufacturer | Rockwell American | Dexter Axle |
| Part Number | STP-Tandem 7k Brake Axle Kit |
| Model | STP-Tandem 7k Brake Axle Kit |
#2 · Best Narrow-Frame Fit
2. Salo Trailer Parts 5,200 lb Kit
Best for: 72-inch-frame builds with tires included.
Why it ranks #2: Its 10,400-pound total capacity, 85-inch hub face, and 70-inch spring center target most 72-inch-wide frames; mounted tires are included.
Mounted ST225/75R15 radial tires on 6-lug wheels come with this 5,200-pound tandem kit, combining running gear and rolling components in one package. Its 85-inch hub face and 70-inch spring center are listed for most 72-inch-wide trailer frames.
Two 5,200-pound tandem axles provide a stated 10,400-pound total capacity, while the 85-inch hub face, 70-inch spring center, and 3-inch axle tube describe the layout. Those dimensions are listed for most 72-inch-wide frames. The kit also includes electric-brake axles, leaf springs, U-bolts, and hangers, supplying suspension hardware with the axles. Mounted ST225/75R15 radial tires on 6-lug wheels reduce the need to source those rolling components separately; the 6-on-5.5-inch pattern defines wheel fit.
- 10,400-pound total capacity from 5,200-pound tandem axles.
- 85-inch hub face and 70-inch spring center listed for most 72-inch frames.
- Includes electric-brake axles, leaf springs, U-bolts, and hangers.
- ST225/75R15 radial tires are mounted on 6-lug wheels.
- Its 85-inch hub face and 70-inch spring center limit it to matching trailer layouts.
Skip it if you have a 76-inch-wide frame needing 89-inch hub face and 74-inch spring center; the Rockwell American 5,200 lb Tandem Trailer Axle Kit lists those dimensions.
This Salo Trailer Parts kit suits builders or owners equipping a 72-inch-wide trailer who want tires, wheels, and suspension components together. Its 85/70-inch geometry and 6-on-5.5-inch pattern define compatibility.
Full product details
| Brand | Salo Trailer Parts |
|---|---|
| Item model number | STP-5200-T-DB-RGK-655-8570 |
| Manufacturer | Rockwell American | Dexter |
| Part Number | STP-Tandem 5.2k Brake Axle Kit |
| Model | 5200 lb Tandem Dual Electric Brake Trailer Axle Running Gear Kit |
Listed on Amazon as: 5200 lb Tandem Trailer Axle Kit, 85 in Hub Face, 70 in Spring Center, 6 on 5.5 Bolt Pattern, Electric Brake Axles, Running Gear Kit
View on Amazon#3 · Best Standard Fit
3. Rockwell American 5,200 lb Kit
Best for: 10,400-pound tandem running gear.
Why it ranks #3: Two 5,200-pound electric-brake axles deliver 10,400 pounds total, with an 89-inch hub face and 74-inch spring center for 76-inch frames.
Two 5,200-pound electric-brake axles provide this kit with 10,400 pounds of stated tandem capacity, placing it between lighter and heavier axle configurations. Its 89-inch hub face and 74-inch spring center are specified for 76-inch-wide trailer frames, alongside a 6-on-5.5-inch pattern.
The 5,200-pound rating per axle and 10,400-pound combined capacity establish the kit's load-rating boundary for tandem utility, cargo, boat, and landscape trailers. Its 89-inch hub face and 74-inch spring center specify the layout for 76-inch-wide frames, while the 6-on-5.5-inch bolt pattern determines wheel matching. Two electric-brake axles arrive with double-eye springs, U-bolt kits, equalizers, and shackles, bringing key suspension and hanger components together for installation.
- Two 5,200-pound electric-brake axles provide 10,400-pound tandem capacity.
- Specifies 89-inch hub face and 74-inch spring center for 76-inch frames.
- Uses a 6-on-5.5-inch bolt pattern.
- Includes double-eye springs, U-bolt kits, equalizers, and shackles.
- The kit's 6-on-5.5-inch pattern restricts it to compatible wheels.
Skip it if you need 85-inch hub face and 70-inch spring center; the Salo Trailer Parts 5200 lb Tandem Trailer Axle Kit lists that geometry.
This Rockwell American kit suits owners replacing tandem electric-brake running gear on a 76-inch-wide trailer needing 10,400-pound capacity. Its 89/74-inch dimensions and 6-on-5.5-inch pattern are essential fit constraints.
Full product details
| Brand | Rockwell American |
|---|---|
| Item model number | Tandem Brake 5.2K RG w/ Hangers 89/74 |
| Manufacturer | Rockwell American |
| Part Number | Tandem Brake 5.2K RG w/ Hangers 89/74 |
| Model | Tandem 5,200 lb Brake Axles Running Gear Kit |
| Package Dimensions | 97 x 40 x 18 inches |
| Special Features | 2 yr Manufacturers Warranty on Axles, 32 oz Johnson Trailer Parts Insulated Mug, Electric Brakes, Posi-Lube Spindles, Powder Coated Axles, Tandem 5,200 lb Axles |
Listed on Amazon as: 5,200 lb Tandem Trailer Axle Kit – Electric Brake Axles – Full Suspension Running Gear Kit – 89” Hub Face / 74” Spring Center – 10,400 lb Capacity
View on Amazon#4 · Best E-Z Lube Fit
4. Dexter 3,500 lb Tandem Kit
- Weight: 200 lb
Best for: Wide-frame 3,500-pound axle replacements.
Why it ranks #4: This 7,000-pound kit includes two electric-brake axles and full suspension gear, with a 95-inch hub face, 80-inch spring center, and E-Z Lube.
A 95-inch hub face paired with an 80-inch spring center sets this Dexter kit apart for trailers using that wider axle layout. Its two 3,500-pound electric-brake axles deliver 7,000 pounds of tandem capacity, with E-Z Lube identified in the title for maintenance-conscious owners.
The stated fit is for 82-inch-wide trailer frames, with a 95-inch hub face, 80-inch spring center, and 5-on-4.5-inch bolt pattern. Those dimensions make frame and wheel layout central to choosing it. The package combines two electric-brake axles with double-eye springs, U-bolt kits, equalizers, and shackles, bringing suspension components into the same running-gear kit. E-Z Lube is a named feature, while the 3,500-pound rating per axle establishes its capacity boundary.
- Two 3,500-pound electric-brake axles give 7,000-pound tandem capacity.
- 95-inch hub face and 80-inch spring center are specified for 82-inch frames.
- Includes springs, U-bolt kits, equalizers, and shackles.
- E-Z Lube is specified in the product title.
- The 5-on-4.5-inch bolt pattern excludes trailers requiring a different wheel pattern.
Skip it if you have a 76-inch-wide frame with 89-inch hub face and 74-inch spring center; the Rockwell American 5,200 lb Tandem Trailer Axle Kit matches those dimensions.
This Dexter kit fits buyers replacing tandem running gear on an 82-inch-wide trailer with the listed 95/80-inch geometry. Its 7,000-pound capacity and 5-on-4.5-inch pattern set the application limits.
Full product details
| Brand | Johnson Trailer Parts |
|---|---|
| Item Weight | 200 pounds |
| Item model number | D35ETBKTZL-95/80-NW |
| Manufacturer | Dexter Axle |
| Part Number | D35545ESTZL0850070001 |
| Model | Dexter 3,500 lb Tandem Axle Brake Kit – 7,000 lb Capacity, E-Z Lube, 5 on 4.5” |
Listed on Amazon as: Dexter 3,500 lb Tandem Trailer Axle Kit – Electric Brake Axles – Full Suspension Running Gear Kit – 95” Hub Face / 80” Spring Center – E-Z Lube – Made in USA – 7,000 lb Capacity
View on Amazon#5
5. Johnson Trailer Parts 3,500 lb Kit
- Weight: 200 lb
Best for: Mixed brake-and-idler axle setups.
Why it ranks #5: The 7,000-pound kit combines a Dexter electric-brake axle with an idler axle, plus suspension hardware, for a 89-inch hub face and 74-inch spring center.
One electric-brake axle and one idler axle make this 3,500-pound tandem kit a specific choice for trailer builds needing those two axle types together. Its 89-inch hub face and 74-inch spring center target most 76-inch-wide trailer frames, with a 5-on-4.5-inch wheel pattern.
The kit specifies 3,500-pound axles and 7,000-pound total capacity, plus a 2-3/8-inch axle tube; these details help bound its intended running-gear configuration. The 89-inch hub face and 74-inch spring center identify its layout for most 76-inch-wide frames. Dexter electric-brake and idler axles are supplied alongside double-eye springs, U-bolt kits, equalizers, shackles, and hardware, consolidating mounting components. The 5-on-4.5-inch bolt pattern is a central wheel-compatibility consideration.
- Includes one Dexter electric-brake axle and one Dexter idler axle.
- 7,000-pound tandem capacity with 3,500-pound axles.
- Lists 89-inch hub face and 74-inch spring center for most 76-inch frames.
- Includes springs, U-bolts, equalizers, shackles, and mounting hardware.
- Its 5-on-4.5-inch bolt pattern limits compatibility with other wheel patterns.
Skip it if you need two electric-brake axles; the Johnson Trailer Parts Dexter 3,500 lb Tandem Trailer Axle Kit lists electric brakes on both axles.
This kit suits trailer builders or repairers whose setup calls for one electric-brake axle and one idler axle. Check its 89/74-inch geometry, 5-lug pattern, and 7,000-pound total rating against the application.
Full product details
| Brand | Johnson Trailer Parts |
|---|---|
| Item Weight | 200 pounds |
| Item model number | D35T8974-EBI-KIT |
| Manufacturer | Dexter Axle |
| Part Number | D35T-EBI-KIT |
| Model | 3500 lb Tandem Axle Kit – Electric Brake and Idler |
Listed on Amazon as: 3500 lb Tandem Trailer Axle Kit, 89 in Hub Face, 74 in Spring Center, 5 on 4.5 Bolt Pattern, Electric Brake and Idler Axles, Complete Install Kit
View on Amazon#6
6. Polar Trailer Tandem Axle Kit
- Weight: 41 lb
Best for: Polar HD1200 and HD1500 owners.
Why it ranks #6: This kit is specifically for Polar HD1200 and HD1500 trailers and supplies tandem arms and wheels, rather than a general-purpose axle-and-suspension running-gear kit.
The tandem walking-arm arrangement lets a compatible single-axle Polar trailer convert to a tandem setup, adding a second axle position for hauling work and recreation. Model 8251 includes two tandem arms and two wheels, and is specified for Polar HD1200 and HD1500 trailers.
This is a model-specific replacement or conversion kit rather than a general-purpose axle package: compatibility is listed for Polar HD1200 and HD1500 trailers, and the tandem arms are sold in pairs. Heavy-duty welded steel brackets straddle each end of the axle to distribute weight, including on top-capacity loads, supporting a more stable load arrangement. Two wheels are included to help restore the tandem setup. The supplied facts do not state axle ratings or general frame dimensions, so the Polar model fit is the defining boundary.
- Compatible with Polar HD1200 and HD1500 trailers.
- Tandem walking arms support conversion from a single-axle Polar trailer.
- Includes two tandem arms and two wheels.
- Welded steel brackets straddle axle ends to distribute weight.
- Compatibility is limited to Polar HD1200 and HD1500 trailer configurations.
Skip it if you need a general-purpose electric-brake axle kit; the Salo Trailer Parts 5,200 lb Tandem Trailer Axle Kit includes electric-brake axles and suspension hardware.
Polar HD1200 or HD1500 owners seeking a tandem walking-arm conversion or replacement are the intended buyers. Its model-specific fit and lack of a listed axle-capacity rating limit broader trailer applications.
Full product details
| Brand | Polar Trailer |
|---|---|
| Item Weight | 41 pounds |
| Item model number | 8251 |
| Manufacturer | Clam Corporation |
| Dimensions | 25 x 11 x 11 inches |
| Additional Information | Important Information Small parts. Not for children under 3 yrs. |
Listed on Amazon as: Polar Trailer Tandem Axle Kit Model 8251
View on AmazonAvoiding Fitment Mismatches
A capacity rating does not confirm that an axle kit will fit your trailer; compare the mounting dimensions and wheel pattern before selecting one. The listings show why: two kits rated at 10,400 pounds differ in fitment, with Rockwell American 5,200 lb Kit listing an 89-inch hub face and 74-inch spring center, while Salo Trailer Parts 5,200 lb Kit lists 85 inches and 70 inches. The first targets most 76-inch-wide frames; the second targets most 72-inch-wide frames.
Bolt patterns also differ across the options, including 6 on 5.5 inches and 8 on 6.5 inches. A mismatch can prevent the hubs or suspension from aligning with the trailer’s existing setup.
Measure the old assembly using the same reference points as the listing, and confirm the frame width and wheel bolt pattern rather than relying on a general trailer category.
What the Kit Includes—and What It Does Not
A complete running-gear kit can reduce the need to source suspension pieces separately, but included components vary and should not be assumed. Several options list axles, double-eye springs, U-bolts, hangers, equalizers, and shackles; Salo Trailer Parts 7,000 lb Tandem Axle Kit also specifies tires pre-mounted on wheels. Johnson Trailer Parts 3,500 lb Kit is different: it pairs one electric-brake axle with an idler axle, rather than two electric-brake axles.
Polar Trailer Tandem Axle Kit is a further departure, supplying tandem arms and wheels for compatible Polar trailers instead of a conventional axle-and-suspension package. This distinction matters when replacing a complete tandem assembly versus adding a trailer-specific walking-arm arrangement.
Before purchase, check the item description for the exact parts included and identify any existing components you intend to retain.
How to Choose Tandem Trailer Axles
Capacity per Axle and Total Rating
Choose an axle rating that suits the trailer’s required load, and compare both the per-axle and combined figures. The complete axle kits span 3,500 pounds per axle and 7,000 pounds total, 5,200 pounds per axle and 10,400 pounds total, and 7,000 pounds per axle and 14,000 pounds total. Salo Trailer Parts 7,000 lb Tandem Axle Kit serves buyers who need the highest listed capacity; either 5,200-pound kit fits a middle capacity requirement.
Dexter 3,500 lb Tandem Kit or Johnson Trailer Parts 3,500 lb Kit suits a lower stated capacity. The Polar kit lists compatibility with particular trailer series, not a comparable general axle capacity.
Confirm the trailer’s own rated limits before treating axle capacity as the load rating.
Hub Face, Spring Center, and Frame Width
Match the listed hub face and spring center to your trailer’s existing measurements before selecting a kit. The options span hub faces of 85 to 95 inches and spring centers of 70 to 80 inches. The 85/70-inch Salo Trailer Parts 5,200 lb Kit is specified for most 72-inch-wide frames; 89/74-inch options are listed for most 76-inch frames.
Dexter 3,500 lb Tandem Kit has the largest listed dimensions at 95 inches hub face and 80 inches spring center, for most 82-inch-wide frames. Buyers replacing an existing assembly should prioritize matching measurements; builders choosing a new frame should select the kit and frame as a coordinated fit.
Do not infer compatibility from axle capacity or brand alone.
Brake, Wheel, and Included Gear
Check whether the kit’s brake setup, bolt pattern, tires, and suspension parts match the components you need. Most listed general-purpose kits use electric brakes, but Johnson Trailer Parts 3,500 lb Kit combines one electric-brake axle with an idler axle. Bolt patterns vary: the 3,500-pound Dexter kit lists 5 on 4.5 inches, the 5,200-pound kits list 6 on 5.5 inches, and the 7,000-pound Salo kit lists 8 on 6.5 inches.
Salo Trailer Parts 7,000 lb Tandem Axle Kit and Salo Trailer Parts 5,200 lb Kit include mounted tires; the other general-purpose listings do not specify tires in the supplied details. Buyers wanting a tire-and-wheel package should favor those Salo kits, while those reusing wheels should verify their pattern.
Which Tandem Axle Kit Should You Choose?
Choose Salo Trailer Parts 7,000 lb Tandem Axle Kit if your trailer matches its 89-inch hub face, 74-inch spring center, and 8-on-6.5-inch pattern and you need the highest listed capacity, 14,000 pounds total. For most 72-inch-wide frames needing 10,400 pounds total, Salo Trailer Parts 5,200 lb Kit has an 85/70-inch fit and includes mounted tires. If your 76-inch frame needs the same 10,400-pound capacity with an 89/74-inch fit, choose Rockwell American 5,200 lb Kit.
Dexter 3,500 lb Tandem Kit fits buyers needing 7,000 pounds total and a 95/80-inch fit; Johnson Trailer Parts 3,500 lb Kit offers a brake axle paired with an idler axle. Select Polar Trailer Tandem Axle Kit only for compatible HD1200 or HD1500 trailers.
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Frequently Asked Questions
How do I measure hub face and spring center on my trailer?
Measure hub face from one wheel-mounting surface to the other across the axle. Measure spring center from the center of one leaf spring to the center of the other. Compare both measurements with the kit listing, and verify bolt pattern and other fitment details before ordering; matching capacity alone does not confirm fit.
How much axle capacity should I select for my loaded trailer?
Choose capacity that accommodates the trailer’s loaded weight, while also respecting the trailer’s rated limits. Add the capacities of the axles to understand their combined rating, but do not treat that number as permission to exceed any other component’s rating. The listed kits range from 7,000 to 14,000 pounds total capacity.
Can I replace only the axles without replacing the suspension components?
Yes, if the existing suspension components are compatible, serviceable, and suitable for the replacement axles. Check spring dimensions, hanger and equalizer arrangement, and axle fitment before buying. A complete running-gear kit can include suspension parts, but replacing those parts is not automatically required when changing axles.
What does a kit with one brake axle and one idler axle provide?
It provides an electric-brake axle paired with an idler axle, rather than two brake axles. The listed 3,500-pound kit describes this configuration and also specifies an 89-inch hub face, 74-inch spring center, and 5-on-4.5 bolt pattern. Confirm that this arrangement matches your trailer’s braking needs and fitment.
Which measurements should I verify before choosing a kit?
Verify hub face, spring center, and wheel bolt pattern against your trailer. For example, the listed 10,400-pound kits have either an 89/74-inch fit or an 85/70-inch fit, while the 14,000-pound kit specifies an 89/74-inch fit and an 8-on-6.5-inch pattern. Check every listed fitment detail before selecting.
Final Words
Start with fitment, not capacity alone: measure hub face and spring center, confirm the bolt pattern, and compare the kit’s total rating with your loaded trailer and its limits. The Salo 7,000-pound kit leads this lineup when its 89/74-inch fit and 8-on-6.5-inch pattern match. For other needs, the 5,200-pound kits offer different fits, while the Dexter, brake-and-idler, and Polar options suit more specific applications.
