Bought the thule xt3 easy fold from the EU (I am in the US), which works with the European swan style tow bar.
I bought the 50mm tow ball with a long shank and the tow bar for the ball.
I am going to get the base of the ball welded to tow bar so it never turns.

How will the bike rack stay in place on the tow ball, what would stop the bike rack from turning left or right when braking/turning at higher speeds if the ball and shank are both round? The bike rack locks on the ball and the shank and doesn't look as if it's going to move/turn, but anyone knows how the bike rack on a tow ball system works?I don't want to damage the bumper etc. Also, the ball shank is round, no flat area etc on the shank.
The European tow bar is flat around the shank area to stop the bike rack from turning?
Please provide some input

 

I'm of no use but am genuinely curious why you decided on an EU spec bike rack when so many great options exist for the US 2" receiver.

1.25" receiver would not be something I'd hang my bikes on.

I'm sure there is a reason. I'm just being nosy I guess.

 

I needed a 3 bike solution, all the US options including Thule were 2+2 with double the weight. Storage of the 4 bike rack was an issue.
The thule xt3 is a 3 bike solution that folds easily. It is more costly with both $ and time to make it work, but I think I would rather have less weight.
Also wanted to stay with the Thule brand ..

 

Thank you for entertaining my nosiness.

Best of luck with the mods.