pic: Unobtainium 6wd - Cantilevered, Dead-Axle, Slot-Tensioned Drivetrain

[JamesCH95]

Cantilevered shoulder bolts can take a lot of load. I used them in an FSAE car suspension rocker that saw around 5,000lbf. The trick is to get the shoulder supported and eliminate bending stresses from any threaded portions. The only serious issue I can see in your design is how the shoulder bolts are connected to the rail.



In this picture near the left-hand edge about 1/3 of the way down you can see where we used a 5/8" (1/2"?) shoulder bolt on the suspension rocker. About half of its length passed through a steel mounting point, then went through a needle bearing in the rocker, and was captured with a nut on the inside of the car. We sandwiched thrust bearings on either side of the rocker so we could clamp everything down very tightly yet still spin it by hand.

I hope you find this useful *cough* needle bearings in wheels *cough*