50mm Square Stub Axle – ALKO 3T Marine Turn

SKU: N/A Category: Axles Tags: Australian Made, Couplemate™ Core Brand: Couplemate

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Price range: $71.36 through $76.39 Inc.GST

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50mm Square Stub Axle – AL-KO 3T Marine Turn

Heavy-duty 3-tonne marine-grade square stub axle kit designed for maximum corrosion resistance and reliable towing performance in harsh saltwater environments. Complete with premium NSK bearings and a high-grade caravan seal.

Product Description

The 50mm Square Stub Axle (AL-KO 3T Marine Turn) is engineered specifically for boat trailers, heavy-duty caravans, and commercial trailers operating near marine environments. It features a specialised marine machined turn to accommodate a dedicated seal collar, preventing water ingress and protecting your bearing system from rust and premature wear. Machined from high-tensile steel, this axle kit comes fully equipped with industry-leading NSK bearings, a robust caravan marine seal, and secure split-pin fastening hardware to ensure ultimate road safety and longevity under maximum load capacities.

Key Features

Marine-Grade Engineering: Features an AL-KO 3T Marine machined turn with an included seal collar to block saltwater and road grime.
Premium Japanese Bearings: Packed with authentic, high-capacity NSK inner and outer tapered roller bearings for smooth rotation.
Maximum Security Hardware: Includes a heavy-duty 12 TPI castellated nut, 5mm split pin, and matching washer for absolute hub retention.
Heavy-Duty Seal: Equipped with a specialised 2t–3t caravan marine seal (64607) to keep grease clean and securely contained.
Robust Dust Cap: Supplied with a 3-inch (75mm) 3-tonne steel dust cap to protect the external bearing assembly from impact and dirt.

Technical Specifications

Specification Item	Details
Axle Size / Profile	50mm Solid Square Profile
Machined Turn Profile	AL-KO 3T Marine Turn (with Seal Collar)
Weight Capacity	Up to 3,000kg (3 Tonnes) per pair
Inner Bearing Type	NSK 30210J x 2.25t Tapered Roller Bearing
Outer Bearing Type	NSK 15123/15245J x 2.25t Tapered Roller Bearing
Marine Hub Seal	2t – 3t Caravan Seal (Part No. 64607)
Thread Type & Nut	12 TPI Thread with Castellated Nut
Dust Cap Diameter	3 inch / 75mm (3t rated)
Split Pin Size	5mm Heavy-Duty Split Pin

Frequently Asked Questions

What makes this stub axle specifically a “Marine” axle?

This axle profile features a specialised machined surface called a marine turn. It includes a fitted stainless steel or brass seal collar. This collar creates a smooth, perfectly round surface for the waterproof marine seal to ride on, preventing saltwater from creeping past the hub into your bearings.

What is the benefit of NSK bearings over unbranded options?

NSK is a world-renowned Japanese bearing manufacturer. Their bearings feature tighter manufacturing tolerances and higher-grade steel, dramatically reducing friction, heat build-up, and mechanical failure risks under heavy 3-tonne loads.

Does this kit fit standard 2-tonne trailer hubs?

No. This stub axle is rated and machined specifically for 3-tonne capacities. It requires heavy-duty 3t hubs that match the large outer diameters of the NSK 30210J and 15123/15245J bearing cups.

Helpful Resources & Store Links

Browse compatible high-capacity trailer components on the AL-KO Axles & Suspension Catalogue.
Ensure your build complies with heavy light-trailer dimensions by checking the Australian Government Vehicle Standards Bulletin 1 (VSB1).
Review safety compliance, overall ATM requirements, and towing laws via the National Heavy Vehicle Regulator (NHVR) portal.

There are no FAQs for this product.

Additional information

Weight	9 kg
Dimensions	40 × 5 × 5 cm
Stub Length	350mm, 400mm

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.