Might seem like a stupid question, but what is the difference between the three types?
I know a cabriolet is of the ‘folding soft top’, so i guess a covertible maybe a folding hard top?
Not sure about Roadster though, as have seen some convertibles advertised for sale as
‘Roadsters’??
Cabriolet is usually used for cars with a soft top based on a standard car with a tin top, e.g. Golf, Audi A3, Escort (!).
Convertible is a catch all term for any cars with a folding roof, metal or fabric, e.g. MX5, Audi TT, Peugeot 207/308 CC, Megane etc
Roadster is an older term for a sports car specifically designed with a folding roof, e.g. MGB, MX5, Jaguar E Type.
(Of course, this is complicated by the MGB GT, MX5 Coupe, E Type coupe, lol)
My opinion.
Thanks “72dudes”
Noticed on my insurance certificate for my 04 plate soft-top, it states ‘cabriolet’, so this i guess goes against
what you say, i thought the MX-5 was originally designed as a soft-top and therefore they should be called
Roadsters? And why does everything have to be complicated?-----I would tend to agree with your comment.
Just checked dictionary : Convertible=A car with a folding or detachable roof. Cabriolet=A car with a roof that folds down 
(no difference there then - lol)
Roadster=An open-top car with 2 seats. Guess if you own a ‘5’ then (unless a coupe) you have a Roadster/Cabriolet/Convertible! 