A true 4,000 lb trailer axle is not listed among these options. The closest single-axle choices are the 3,500 lb models, while the Rockwell American kit provides two 7,000 lb axles for a tandem setup. Choose based on your trailer’s required capacity and, just as importantly, its hub-face and spring-center measurements. The 3,500 lb kit is best for buyers needing suspension parts with an axle; the standalone axles suit replacement needs. Verify the axle rating and full trailer setup before buying.
| Product | Listed capacity | Best suited for |
|---|---|---|
| Getanye 61-inch axle | 3,500 lb | Light-duty replacement with included U-bolts |
| Rockwell American tandem kit | Two 7,000 lb axles | Matching tandem trailer frames |
| Yunnergo 89-inch axle | 3,500 lb | Replacement requiring 89-inch hub face |
| Getanye 85-inch axle | 3,500 lb | Light-duty trailer with 85-inch hub face |
| Trailer Parts Outlet single-axle kit | 3,500 lb | Single-axle installation with suspension parts |
Getanye 61-Inch 3,500 Lb Axle
This is a light-duty idler axle rated for 3,500 lb, with a 61-inch hub face, 46-inch spring center, and 5-on-4.5-inch bolt pattern. It has a 2⅜-inch tube, welded spring pads, and an included U-bolt kit. The listing describes it as pre-greased and intended for applications including utility, boat, cargo, and RV trailers.
Best for: Buyers replacing an axle on a light-duty trailer whose measurements match this model. It is selected for its stated fit dimensions and included U-bolts. Limitation: Its listed rating is 3,500 lb, not 4,000 lb, and it is not a complete suspension kit.
Rockwell American 7,000 Lb Tandem Kit
This complete running-gear kit includes two 7,000 lb electric-brake axles, double-eye leaf springs, U-bolt kits, a tandem hanger kit, equalizers, shackles, and ST235/80R16 radial tires mounted on eight-lug wheels. The listed dimensions are 95 inches hub face and 80 inches spring center, with a stated fit for 82-inch-wide trailer frames. The listing also specifies 12-by-2-inch electric brakes and Posi-Lube spindles.
Best for: Owners replacing a compatible tandem setup who need axles and suspension components together. It is selected for its extensive kit contents and stated dimensions. Limitation: This is not a single 4,000 lb axle; its two-axle capacity and fit requirements differ substantially.
Yunnergo 89-Inch 3,500 Lb Axle
This 3,500 lb, five-lug axle is listed with an 89-inch hub face and 74-inch spring center. The manufacturer describes its steel tube as high-strength and identifies car, landscape, ATV, and RV trailers among its possible applications. The product description also emphasizes load distribution and stability, but does not specify a complete suspension kit or additional included hardware.
Best for: Buyers seeking a standalone axle with these particular measurements for a compatible trailer. It is selected as another dimensional option for light-duty replacement. Limitation: Confirm the bolt pattern and other component details with the seller or product listing before purchase; the supplied features do not state them.
Getanye 85-Inch 3,500 Lb Axle
This idler axle has an 85-inch hub face, 70-inch spring center, 5-on-4.5-inch bolt pattern, and five-lug hubs. The listing identifies a 3,500 lb capacity and describes the axle for light-duty utility, boat, car-hauling, landscape, cargo, and RV trailers. It also states that the axle is intended for a 72-inch-wide frame.
Best for: Buyers whose existing axle and trailer frame match the listed dimensions. It is selected because it provides a distinct fit option among the 3,500 lb replacements. Limitation: It is an idler axle rated below 4,000 lb, so it does not meet a requirement for a single axle rated at that amount.
Trailer Parts Outlet 3,500 Lb Axle Kit
This single-axle kit includes a 3,500 lb idler axle, double-eye hanger kit, four-leaf double-eye springs, and two 1,750 lb U-bolt kits. The listed dimensions are 89 inches hub face and 74 inches spring center, with a 5-on-4.5-inch bolt pattern. The product description specifies high-strength steel construction and high-temperature axle grease.
Best for: Buyers who need an axle and several suspension parts in one package for a small utility, cargo, or ATV trailer. It is selected for its included hardware and spring components. Limitation: Its 3,500 lb rating is not a substitute for a properly rated 4,000 lb axle.
Buying Guide: How to Choose a Trailer Axle
Is a 3,500 lb axle enough for a 4,000 lb requirement?
No. A listed 3,500 lb axle should not be treated as a 4,000 lb axle. Check the trailer manufacturer’s specifications and the ratings of the axle, tires, wheels, springs, and other load-bearing parts. The system’s practical limit depends on its components, and replacing one part does not automatically increase the trailer’s rated capacity.
Which measurements should you check before ordering?
Compare hub-face distance, spring-center distance, bolt pattern, and axle tube details against your existing setup. Hub face is measured between the wheel-mounting surfaces; spring center is measured between the spring mounting locations. Also check frame width and whether the trailer uses an idler axle or electric brakes. Do not choose by axle capacity alone.
Should you choose a standalone axle or a kit?
A standalone axle can suit a replacement when the springs and hardware remain serviceable and compatible. A kit may be more convenient when suspension parts also need replacement, but verify every included component and dimension. The tandem Rockwell American package is for a different configuration from the single-axle products.
Frequently Asked Questions
Are any of these products rated at 4,000 lb?
No. The single axles listed here are rated at 3,500 lb. The Rockwell American product is a tandem kit with two 7,000 lb axles.
Can two 3,500 lb axles carry 7,000 lb?
The axle ratings add up to 7,000 lb nominally, but that does not establish the trailer’s safe payload or overall rating. Tires, wheels, suspension, frame, and the trailer manufacturer’s specifications also matter.
What does hub face mean?
Hub face is the distance between the axle’s wheel-mounting surfaces. It helps determine wheel position and must match the trailer’s intended setup.
What is spring center?
Spring center is the distance between the axle’s spring mounting points. It should match the trailer’s suspension layout to support proper installation and alignment.
Does an idler axle include brakes?
The listed Getanye and Trailer Parts Outlet products are described as idler axles. The provided features do not list brakes for them. The Rockwell American kit specifically includes electric-brake axles.