Snake-bite, why Towcar-trailer weight ratios matter

The caravan clubs recommend that the Maximum Technically Permitted Laden Mass (MTPLM) of a caravan should not exceed 85% of the kerbside mass of the towcar. Here is an example of the reason why:

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This classic Rolls-Royce Silver Shadow had just been collected by its new owner. He was transporting it on a trailer to Spain for a classic car rally. He was towing it behind a Toyota RAV 4 with a kerb weight, depending on model, of between 1.5 and 1.7 tonnes. The weight of the Silver Shadow would be about 2.1 tonnes, giving a weight ratio of around 125%, before taking account of the trailer on which it was being carried.

Within a few miles of the driver setting off, the trailer began to snake, and it eventually threw the Rolls- Royce off. The A350 near Stoney Gutter, Wiltshire, was closed for more than three hours while the debris was cleared. To make matters worse, the owner later discovered that the Rolls Royce’s insurance did not come into effect until midnight on the day of the accident, so that he cannot recoup the cost of the damage.