It’s crucial for anyone involved in towing, especially across different regions, to understand a key difference in standards: the tow ball sizes used in Europe and North America. Specifically, Great Britain transitioned from the imperial 2-inch tow ball to the European metric 50mm tow ball over two decades ago. While the size difference might seem negligible – only about 0.8 mm, with the 50mm EU tow ball being slightly smaller – this subtle variation can have significant implications for towing safety.
During the transition period in Great Britain, both 2-inch and 50mm systems were in use. Anecdotally, some individuals, like the author of the original note, have even towed US trailers with EU tow balls without immediate issues over short distances and with lighter loads. In one instance, a US SAE-spec trailer coupler was used with a European-spec tow ball for approximately 6,000 miles without apparent problems, towing a camper trailer with a dry weight of about 1,500 pounds.
However, historical accounts from older British internet forums discussing towing accidents during this transition period suggest a potential link between mixing and matching tow ball and coupler systems and towing incidents. While these stories are largely apocryphal and lack definitive proof, they serve as a cautionary reminder. The exact nature of the mismatch in these older stories – whether the EU-spec side was the tow ball or the coupler – remains unclear. Despite the seemingly minor 0.8mm diameter difference, the potential for compromised safety when using mismatched systems should not be ignored.
It’s important to consider that a horse trailer originating from Britain, if intended for sale in North America, would likely be equipped with a North American SAE-spec coupler to ensure compatibility. Therefore, for trailers specifically manufactured for the North American market, this tow ball size difference might be a non-issue.
Ultimately, the information serves as a valuable reminder for anyone towing trailers, particularly when dealing with equipment from different regions. Always verify the compatibility of your tow ball and coupler to ensure safe and secure towing practices.
