[noemon]

I've towed my jet ski with a 3 litre diesel cayenne for years. And that means the yearly 600 mile round-trip from its garage(Glyfada) to the beach(Elafonisos) and back, and it's almost daily in and out for 4-5 weeks every summer. no issue whatsoever, can't imagine an x3 or x5 struggling with trailers up to 1 tonne total weight.

That boat above is a different story. That must certainly weigh more than 1 tonne with the trailer and that is beyond a regular car's capabilities.

I would tow something like that in an emergency or perhaps force the car to suffer it once in a non-emergency but I would really not pull a trailer as big and heavy as that on a recurring basis with a standard car. The car would be destroyed fairly quickly, clutches, brakes, tyres, even nuts and bolts.

I think 1 tonne is a good upper limit and guide for X5's, Cayennes and such, which places other standard cars on a trailer as no-go's.