Trailer Lug Bolts

fj12ryder wrote:
Bicycle pedals rotate around the axle that is tightened onto the pedal shaft. If the pedal tightened up, it could loosen the axle. Very big difference between that and lug nuts. I don't believe precession enters into the equation.

Then you'd be wrong. Granted, there's normally no movement with properly torqued fasteners. But if there's any movement at all, precession will quickly loosen them all the way. It's a documented fact that it was done. And that's why it was done. It's not done now, because taper seats are used, and hub centric mounting is common.

A lot of semi-tractors and tandems still use left hand threads on the left side (e.g. stud piloted Budd wheels).

Auto lugs.