How To Pick The Right Towball For Your Towing Setup

Towballs come in a range of sizes and standards depending on their country of origin. Selecting the correct towball, and ensuring that it is correctly matched to the trailer coupling, is critical for safety and compliance with New Zealand regulations. Here’s an overview of common towball sizes and the towing requirements for New Zealand.

Common Towball Sizes

• 1 7/8" Towball (47.6 mm): The most commonly used towball in New Zealand, particularly for light trailers with a GTW < 3,500 kg.
• 50 mm Towball: The most widely used towball in Australia, the UK, and Europe. Some light trailers in New Zealand have 50 mm couplings fitted.
• 2" Towball (50.8 mm): Standard in the USA; also used in NZ/Australia for some imported trailers and couplings.
• 2 5/16" Towball (58.7 mm): Widely used in the USA for heavy trailers, caravans, and boat trailers; also used in NZ/Australia for some imported trailers and couplings.
• EU Standard Towball: 50 mm ball, often paired with European-style detachable towbar systems or “gooseneck” ball mounts.
• Pintle Hooks / Heavy-Duty Towballs: Includes a range of specialty pintle hooks, towballs, and couplings for heavy-vehicle, commercial, or military applications.

New Zealand

• Towball Sizes: 1 7/8" (47.6 mm) and 50 mm are both permitted.
• Shank Sizes: 1" threaded shank is most common for towing < 3,500 kg. Light-duty towing is possible with ¾" shanks, though less common.
• Standards: NZ Standards 5467 and 5232 require the ball size, maximum towing mass, and manufacturer’s mark to be displayed.
• Load Ratings: Towballs must be rated at or above the trailer’s maximum towed mass (e.g., 3,500 kg).
• Certification: Heavy-vehicle towballs, towbars, and drawbeams must be certified by an approved engineer with an LT400 certificate.

Australia

• Towball Size: 50 mm.
• Shank Size: 7/8" threaded shank.
• Regulations: Must comply with Australian Design Rules / Standards ADR62 / AS4177.2.
• Markings: Towballs must show size, maximum rating, manufacturer’s mark, and batch code.
• Capacity: Typically rated up to 3,500 kg for passenger vehicles; heavy-duty setups require engineer approval.

United Kingdom

• Towball Size: 50 mm only.
• Regulations: Must comply with EC 94/20 Directive or UNECE Regulation 55.
• Markings: Towballs must carry approval markings and D-value stamps.
• Towing Limit: Restricted to the lower of the vehicle manufacturer’s limit or towball rating.
• Considerations for the New Zealand Market UK-sourced towballs and towbars often do not comply with New Zealand standards, particularly regarding safety-chain attachments. For compliant towing in New Zealand, choose a towbar designed and tested with certified safety-chain attachments.

Europe

• Towball Size: 50 mm towball across all EU countries.
• Regulations: Compliance with UNECE R55 is mandatory.
• Detachable Systems: Widely used; must lock securely with a visible indicator.
• Certification: All towbars and towballs must be type-approved and stamped. 
• Considerations for the New Zealand Market: UK and European sourced towballs and towbars often don’t comply with New Zealand standards, particularly in relation to inferior safety chain attachments. For compliant towing in New Zealand, select a towbar with safety chain attachments that have been designed and tested to meet local requirements.

United States

• Towball Size 1 7/8”: Light trailers, up to approximately 900 kg.
• Towball Size 2”: Common size, up to approximately 3,500 kg.
• Towball Size 2 5/16”: Heavy-duty, up to approximately 6,800 kg or more.
• Regulations: No single federal towball size; governed by the SAE J684 standard.
• Markings: Towballs must be stamped with size and rating.
• Flexibility: Multi-ball mounts are common to accommodate multiple trailer coupler sizes.

Tip: Never assume your towball and trailer coupling are compatible just because they look right. Always check the size stamp on the towball and the markings on the trailer coupling to ensure they are a perfect match. Using the wrong size ball or coupling can almost certainly cause the trailer to detach.