Originally Posted by Chombi1

Just to make things interesting, Simplex actually found it necessary to have a different thread pitch for the mounting bolts used on the clamped on version of the Retrofrictions to the brazed on ones.
Strange , but at least they had the right bolt threads on the brazed on version, so they will screw on to "standard" brazed shifter lugs on most bikes........ but not on to Simplex mounting bands....