The ROP Shop Trailer Axle Kit Pack of 2 — 4 on 4" Idler Hubs & 1 1/4" BT8 Spindles, Bearings & Seals

The ROP Shop Pack of 2 trailer axle kits includes two 4 on 4" bolt idler hubs paired with 1 1/4" round BT8 spindles, bearings, seals, caps and hardware for standard 2,000 lb axle applications.

If you need a complete pair of axle end assemblies for light trailers, utility trailers or lawn equipment trailers, this kit provides matched hubs and spindles with the common 4 on 4" bolt pattern and standard-length spindles. Each hub is rated at 1,250 lb capacity and the pair covers typical 2,000 lb axle setups. The kit ships with inner and outer bearings, double-lip grease seals, caps, lug nuts and spindle castle nuts with pins — everything required to install at both ends of a straight axle with the correct bearing fit.

Will these axle kits fit my trailer axle?

Compatibility depends on a few measurable details of your existing hubs and spindles. Confirm your axle is a straight (non-drop) design and that the spindle length and bearing sizes match the kit's specifications. If your trailer uses non-standard or short spindles, this kit will not fit.

• Spindle: 1 1/4" round BT8 standard length (8 3/4" overall with 4" stub)
• Hub bolt pattern: 4 on 4"
• Bearing sizes: included 1" bearings (inner/outer per hub)
• Seals: double-lip grease seal 1 1/4" I.D. / 2" O.D.

How much weight can each hub and the pair support?

Each idler hub in this package is rated to support up to 1,250 pounds. When installed as a matched set on a single axle, the two hubs together are suitable for a standard 2,000 lb axle rating, taking typical safety margins into account.

• Individual hub capacity: 1,250 lb
• Recommended axle rating when used as a pair: 2,000 lb
• Designed for light-duty trailer and utility applications

What components come in the pack and what tools might I need?

The pack includes two fully loaded hub assemblies and all common hardware to finish installation. Expect to have basic axle service tools on hand, and if you're unsure about torque or bearing preload, a mechanic or trailer shop can help complete the job safely.

• Includes: (2) idler hubs with lug nuts, (2) 1" BT8 spindles with castle nuts, pins and washers
• Also included: 4 inner/outer bearings, (2) double-lip grease seals, (2) 2" grease/dust caps
• Typical tools: torque wrench, bearing packer or grease, socket set, hammer, drift for pin

How do I verify this kit matches my existing bearings and spindle?

Measure your current bearing dimensions and check spindle diameter and overall length against the kit specs. Compare hub bolt pattern to your wheel mounting pattern and confirm the hub face and back spacing align with your brake or wheel setup.

• Check spindle diameter: 1 1/4" for this BT8 spindle
• Measure hub bolt pattern: 4 on 4" centers
• Confirm bearing dimensions and seal I.D./O.D. match existing parts

Who this is for: This dual kit is aimed at DIY trailer owners, small fleet operators and repair shops replacing or upgrading hubs and spindles on light-duty trailers. If you have a straight 2,000 lb axle with standard spindles and matching bearing sizes, the ROP Shop Pack of 2 gives you a complete, matched set. If you’re uncertain about fitment, provide your axle model, spindle measurements and bearing numbers to our product specialists so we can help confirm compatibility before purchase.