I’m intrigued by this one as I wanted to change my older square block type (pre 2006/7) to the new style. Contacted MR to buy a new pair but was told they are not interchangeable, "no can do". As far as I can gather the tubes are a similar size. They appear do have varying degrees of crushing to facilitate a tight fit. However the older version headrest rests on top of the seats, were as the newer style headrests appear to sit a little above the seats. So something subtle with the seat design between age of cars maybe?. Never quite got to the bottom of what the difference was.
I've just swopped mine over Roger, and they fit.
The stalks are the same length. The only visual difference is that the later stalks are slightly indented on the front edge.
So the big ones from the Roadster fit Bumble, but are loose and don't sit all the way down.
The small ones from Bumble fit the Roadster perfectly.
The only thing which is odd is that there's no obvious reason why the big ones don't go all the way down in Bumble.
In the almost six years I've had my Roadster, not once have I used the radio - it's a waste of time. And thankfully Bumble isn't radio prepared.
