2-1/8 x 5-3/8" Square U Bolt Kit with Plates Trailer Boat Axles 1/2" 2 x 2 Tube
Part Number: UBK-2000-SQ
Square u-bolt hardware kit for 2" x 2" square trailer or boat axle tube setups. Includes four square u-bolts, two tie plates, two spring perches, and eight nuts for a complete mounting hardware package.
R&P Knowledge Hub
What this kit supports: This kit is built around a 2" square axle tube with square-bend u-bolts and matching hardware for leaf spring mounting.
What the BOM confirms: The bill of materials shows 4 square u-bolts, 2 tie plates, 2 spring perches, and 8 nuts, so this is more than just loose u-bolts and nuts.
Measurement note: The updated product diagram now carries the dimension callouts directly. For this kit, 1/2" is the rod diameter, 2-1/8" is the width shown on the diagram, and 5-3/8" is the u-bolt length shown on the diagram. It should not be described as an internal length.
Before ordering: Verify 2" x 2" square tube axle size, hardware style, spring seat layout, and matching plate/perch requirements before installation.
R&P Service Insight
On square axle service work, it is important to think of the hardware as a clamping system. The u-bolts, plates, perches, and nuts all work together to keep the spring stack aligned and secured.
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Correct Bend Style: Square-bend u-bolts should match the square axle tube profile
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Complete Hardware Matters: Tie plates and perches are part of the system and should not be overlooked
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Verify Threads and Fit: Check thread condition, perch center hole, and plate width before assembly
Features
- Complete kit includes four square u-bolts, two tie plates, two spring perches, and eight nuts
- Square u-bolts measure 2-1/8" width with 5-3/8" u-bolt length and 1/2" rod diameter
- Designed around 2" x 2" square axle tube applications
- Suitable for trailer and boat axle leaf spring hardware setups using square-bend u-bolts
Specifications
| Specification | Detail |
| Part Number | UBK-2000-SQ |
| Product Type | Square U-Bolt Kit with Plates and Spring Perches |
| U-Bolt Quantity | 4 |
| U-Bolt Bend Style | Square Bend |
| U-Bolt Diameter | 1/2 in |
| U-Bolt Thread | 1/2"-13 |
| U-Bolt Width | 2-1/8 in |
| U-Bolt Length | 5-3/8 in |
| Axle Tube Fit | 2 in x 2 in square tube |
| Tie Plates Included | 2 |
| Spring Perches Included | 2 |
| Spring Perch Center Hole | 0.625 in |
| Nuts Included | 8 |
| Application | Trailer / boat axle leaf spring mounting hardware |
Measurement Reference
The product image is the measurement reference. The 5-3/8" callout is the u-bolt length shown on the diagram, not an internal length.
| Measurement | Description | Value |
| Rod Diameter | U-bolt rod thickness | 1/2 in |
| Width | Width shown on product diagram | 2-1/8 in |
| U-Bolt Length | Length shown on product diagram | 5-3/8 in |
Fitment / Application
| Category | Details |
| Axle Style | 2" x 2" square axle tube |
| Suspension Type | Leaf spring setup |
| Hardware Style | Square-bend u-bolts with tie plates and spring perches |
| Important Notes | Confirm axle dimensions, perch layout, spring stack height, and hardware compatibility before ordering or installation |
Included Components
| Quantity | Item | BOM Reference |
| 4 | Square u-bolts, 2.125" x 5.378" x 1/2"-13 | 32443 |
| 2 | U-bolt tie plates | 32491U |
| 2 | Spring perches for 2" square tube, 0.625" center hole | SP-2 |
| 8 | 1/2"-13 u-bolt nuts | UBN-8C |
Verify axle tube size, spring perch requirements, and all hardware dimensions before installation.
UBK-2000-SQ, 2-1/8 x 5-3/8 square u bolt kit, 2 x 2 square tube u-bolt kit, trailer boat axle u-bolt kit, square u-bolt kit with plates, u-bolt kit with spring perches, 1/2 inch trailer axle u-bolts, 32443 32491U SP-2 UBN-8C
