45mm Round Galvanised U-Bolt Kit

SKU: N/A Category: U-Bolts and Kits Tags: U-bolts, ubolt Brand: BoltBiz

Couplemate round galvanised u-bolt for trailer suspension caravan spring suit axles drawbars

Price

$34.25 Inc.GST

U-Bolt Length

Clear

✓ Suits 45mm round axles.
✓ Uses galvanised u-bolts and plates (great for boat trailers).
✓ Easily DIY spring and axle maintenance at home with this complete kit.

Shipping

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45mm Round Axle & Spring U-Bolt Kits | Galvanised

The Couplemate™ 45mm U-Bolt kit for round axles includes galvanised U-bolts, nylock nuts, and fish plates.

Spring U-Bolt Kits are designed to fasten leaf springs to trailer and caravan axles securely. U-bolts link your trailer to the road, so it’s important to use high-quality u-bolts.

Why U-bolts May Be the Major Cause of Accidents. Click here

This U-Bolt Kit is supplied with:

4 x U-Bolts (choose preferred length)
8 x Washers
8 x Nyloc nuts
2 x Fish Plates
2 x Axle Pads/Spacers

45mm Round U-Bolt Specifications

U-Bolts are measured on their internal dimensions to ensure proper fit and alignment with the equipment. See our technical diagram for a visual reference.

Internal U-Bolt Width: 45mm
Internal U-Bolt Leg Length:
- 100mm (4″)
- 115mm (4.5″)
- 125mm (5″)
- 140mm (5.5″)
- 150mm (6″)
- 165mm (6.5″)
- 175mm (7″)
Thread: 1/2″ UNF (12.7mm)
Coating: Traditional hot-dipped galvanised

Couplemate™️ offers these 45mm round U-bolt kits for leaf-spring suspension systems.

Installation (User Guide)

Couplemate™️ 45mm Round U-Bolt Kits make trailer spring maintenance easy.

Place a U-shaped curve over the axle beam.
Align the centre spring bolt and U-bolt legs with the fish plate holes.
Secure the fish plate to the leaf spring using the supplied washers and nylock nuts. Tighten nuts to 60Nm with a socket.

Important: Check U-bolts and re-tighten nuts after the first trip and every 250 km thereafter.

Safety Precautions

Do not reuse Nyloc nuts. Nyloc nuts are often less effective after the first use. This is because the nylon material (the key component of a Nyloc nut) has already once conformed to the thread profile.
Do not use a rattle gun to tighten. Rattle guns often tighten U-bolts too fast, too tight, and unevenly. This can cause nylon to overheat and risk undue wear.
Ensure the axle has welded axle pads. If not, use the axle pads supplied with the spring U-bolt kit.

Available U-Bolt Kits

16mm U-Bolts

FAQ: 45mm Round Axle U-Bolt Kit Installation

How do I correctly fit and maintain a 45mm round U-bolt trailer suspension kit?

✔ DO:

Match the profile exactly: Use these round U-bolts only on a true 45mm round axle tube to avoid point-loading stress.
Tighten in a cross pattern: Tighten the nyloc nuts incrementally using an “X” sequence to ensure even clamping pressure across the fish plate.
Check torque after 100km: Brand-new suspension hardware settles under load. Always re-torque for safety after your first trip.

✖ DON’T:

Never mix shapes: Don’t try to force these round U-bolts over a 40mm or 45mm square axle, as it creates unsafe gaps and causes the axle to “walk”.
Do not reuse old U-bolts: Stretched or rusted threads lose their clamping efficiency. Always replace the complete hardware set during a suspension overhaul.
Avoid over-tightening with impact guns: Excessive impact force can strip the 1/2″ threads or compromise the locking capabilities of the nyloc nuts.

Additional information

Weight	4.9 kg
Dimensions	25 × 15 × 5 cm
U-Bolt Length	100mm, 115mm, 125mm, 140mm, 150mm, 165mm, 175mm
U-Bolt Width	45mm
Coating	Galvanised
Stud Thread	1/2" UNF – 490300-ALKO
U-Bolt Application	Spring U-Bolts
Bolt Diameter	12.7mm
Fastener Type	U-Bolt
Spacer Plate Type	Fish Plate, Spring Spacer

Our Service Lifetime Warranty

Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.

Couplemate™ is a manufacturer and vendor of high-quality towing, trailer, and caravan components. Couplemate™ Core Goods and Custom Work are guaranteed to be free of defects for the service lifetime of the product when used as intended.

Warranties are non-transferrable and Couplemate™ requires satisfactory proof of purchase prior to issuing a remedy. The full Couplemate™ Warranty Policy can be found in the Terms & Conditions: Section 8 – Consumer Guarantees & Warranty.

Warranties are in addition to your rights under the Australian Consumer Law. If something is wrong with your order, please contact our team.

60-Day Returns

After 60 years of experience, we know that life has its unpredictable moments.

All Couplemate™ orders (online, over the phone, or in-store) have a 60 day period for change-of-mind returns and exchanges. There are some items that can’t be returned and some returns may incur a 15% restocking fee.

You can view our full policy for change-of-mind returns here.