78-80 Van Diemen lower front A-arm design

The photos show two versions of lower front A-arms for the 78-80 VD. The one on the right is a front lower right and the one on the left is a front lower left. Simon at Universal says the one on the right is how URS makes them. And they have made them this way for decades. In that one the center line of the tubes intersects the centerline of the spherical bearing weld cup. The A-arm on the left, of unknown origin, has the outside of the tubes tangent with the bearing weld cup.

These two "new" (never used) A-arms were in my spares box for 20+ years. I took them out to use them and noticed they are made differently. The lower A-arms currently on my car are made like the one on the left in the photos.

Does anyone know the rest of this story?

Thanks,
Steve

Steve
i think from my memory at VD in 78 that the wishbones did vary depending on whether Arch or Sabre made them. None were made at VD in those days. Other than looks I dont think it matters as the original jig points were the same from 77-80 and it was the one bit of front suspension that wasnt modified for US slicks. Somewhere I have my original assembly notebook for the US RF78 with dims
Phil

Thanks for responding Phil. You assembled many of these back in the day.

The one difference I noticed is that the URS-spec A-arm increased the caster/castor by about 1 1/4 degrees. That's with the rod ends at similar measurements on both A-arms. An overlay of the two A-arms shows the bearing weld cup is about 3/8" forward on the URS-spec. The other difference is that the 40+ year old A-arms appear to be braze welded. The URS-spec A-arms appear to be TIG welded.

If you do find your VD notebook I would love to see it.