Yep same troubles. Using U-clamps won't hold it, and when it pulls forward on right side under torque it can twist that bracket.
You'll need to beef it up. My suggestions, weld in standoffs, use brackets on back side, and cut half-moon 'clamshell' to weld on clamping sides.
Use chain tensioners both sides. Use the third plate option like SBP sold.
Additionally, I dimpled shaft at every set screw location, added lock collars, lots of locktite. Not a single loose nut or screw in over 200 miles.
Note I used a compression collar on left side.
Makes it easier to remove entire shaft from right side if needed w/o breaking down entire shaft.
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