The ultimate authority is the actual Owners Manual that came with the vehicle. In most cases you can do a
Google Search with the year make and model to find one online. But you will want to verify with the actual owners manual of that vehicle to be sure since sometimes the online ones might differ from the actual. Generally speaking you want to look for the section on "Recreational Towing" in the owners manual.
There are users that find out that they can tow four down just fine, going against what the manufacture states. If you go this route you’re on your own if there are any damages, this is why many won’t risk violating the warranty by towing against the owners manual recommendation.
Be sure to check out this thread to -
Towing or packing a Smart Car on the back of a Class A