The thig that makes the bar strong is the material the diameter and wall thickness.
If you want to keep the same diameter go with a thicker wall tube or to one of the stronger chrome molly steels.
However, as mentioned above it appears that your attachment points may be too strong for the vertical travel of the wheel.
I don't know how the bar attaches in an AH but the bar should not bind in vertical movement.
I always preferred Heim joints as they do not bind.