More "for fixin'" my X5 but I was removing all the rattles from my new aluminum 2T floor jack when I noticed how crappy the main wheels were made: the hole through the middle was a cone shape.
Had my brother cut an inset into the hub of the wheel where I could add a 1/2 x 3/4 with 1" flange bronze bushing.
Now the wheels actually use the entire width vs push a dent into the asphalt as they lean 4°
As a bonus, I put o-rings bewteen every touching piece of metal so I can bring the thing with me without going insane.
(Tapping metal is a huge trigger for my misophonia). I came close to throwing it out the window on my last trip home.
The gray is JB Weld to fill the conical space from the unmachined cast iron (the inner hole went from about 19 to 21mm!)