Burley Flex Connector, square tube vs round tube, does it really matter? I have a new flatbed trailer that uses a square tube tow bar instead of a round like my kid trailer has.  Since I'm setup on the Burley system, I need to use a flex connector for the new trailer.  I bought one of each with the trailer so I was prepared when it showed up.  While looking at them either one will fit but the square tube connector has ridges which are just as round as the rest of the connector.  Other than increasing the diameter of the connector, does the ridges really matter, or can I use either one on this trailer?

I'm sure I get no support from Burley since both trailers are not Burley and the packaging for the connectors clearly state not to use them on other trailers.

My kid trailer is a Pacific Voyager II and the new one I bought is a Aosom/Mwave/somebody "wonderer" flatbed.

Flex connector for round towbar:


Flex connector for square towbar:


Here is the side-by-side photo of the connectors I received:
These trailer hitches are interchangeable and I have no issues.  I'm using the round connector in the square tube since it physically fits.  I have put some miles on it on it hauling kids bikes, pulling kids in sleds (recommended to keep the rope out of the tire and carry a spotter), and a 90 mile weekend camping trip.  I have had no issues with it.  

As a bonus here I took a round connector out of another trailer that really has some miles and years on and put it on a new trailer (Trek branded Chariot).  The tongue was squared tubed and too small for the connector but I was able to take a stone grinding wheel to the connector and re-size and shape to get it to fit.  No issues found in it at all.