I want to replace the top shock nut with a standard open nut because the cats electrical connectors have a poor connection with the stock nut on there.

I can't seem to find the right thread pitch though. It appears to be an M12, but M12-1.25 (normal fine thread) does not work.

 

I think its M12 1.5 but I don't have a spare one to check for sure.

 

M12-1.5 is std metric lug nut size and that just slides down the shaft... on Normal (non Cats shocks)

Normal shocks are like 3/8-16 or the metric equivalent. M10-1.5?

Don't know about CATS