This topic has come up before.  If the nut falls off of the bolt the bolt can slide out and the wheel can swing away from the control arm.  If the nuts fall off of the spindle pin the assembly stays together, it's just looser than it was.  The lock pin locks all of the parts together.

Lots of things on the car aren't needed for operation.  You could safety wire the nut on the bolt, or the nuts on the spindle pin, and be about as safe, I guess.  

1 hour ago, Zed Head said:

This topic has come up before.  If the nut falls off of the bolt the bolt can slide out and the wheel can swing away from the control arm.  If the nuts fall off of the spindle pin the assembly stays together, it's just looser than it was.  The lock pin locks all of the parts together.

Lots of things on the car aren't needed for operation.  You could safety wire the nut on the bolt, or the nuts on the spindle pin, and be about as safe, I guess.  

That makes sense, though based on what every Z owner with spindle pin experience knows, the chances of a pin falling out are less than winning Mega Millions AND the Power Ball in the same week. 

I guess I'll use the wedge bolts... and buy lottery tickets. ?

I'd like to mention that in addition to the race car not having a wedge bolt neither does my street car which has had the Arizona Z Car RCAs installed since 2006 which has not been wire tied or pinned. Freedom of movement is key in suspension parts. Remove the lock pin and rotate the strut and RCA. Put in the pin back in and try again. But hey, if you feel more safe with it there fine. 

15 hours ago, gnosez said:

I'd like to mention that in addition to the race car not having a wedge bolt neither does my street car which has had the Arizona Z Car RCAs installed since 2006 which has not been wire tied or pinned. Freedom of movement is key in suspension parts. Remove the lock pin and rotate the strut and RCA. Put in the pin back in and try again. But hey, if you feel more safe with it there fine. 

I am not concerned about a bolt falling out as I am not having a lock pin installed to keep the bolt from turning in the strut housing and galling it out to oval shape.

I see the aftermarket control arms do not have theirs lock pinned like OEM was. That kind of concerns me.

There was a guy selling these 5/8"  bolts with a flat machined for the lock pin some time ago. 

A bolt like that could be used in place of the oem spindle pins I would think. In fact I for one would buy a pair.

Comments and opinions?

I think the the purpose of the lock pin (wedge) is two-fold.

#1 is to keep the pin in place in the strut assembly.

#2 is to keep the pin from rotating so that the proper torque can be applied to both jam nuts.

It may have more to do with the assembly process .........................

That's a good point.  It might actually be that the process of torquing the nuts (they're not really jam nuts, just nuts) is what causes the distortion of the spindle pin at the lock-pin hole.